Lots more changes

.gitignore

@@ -3,6 +3,7 @@
 
 # Run Artifacts
 /*.yaml
+/config.key
 /data/
 
 # Coverage outputs

Makefile

@@ -4,13 +4,13 @@ BIN_DIR := ./bin
 BIN := $(BIN_DIR)/$(APP_NAME)
 CONFIG ?= config.yaml
 
-.PHONY: help run dev generate-config build test test-race fmt clean
+.PHONY: help run dev config build test test-race fmt clean
 
 help:
 	@echo "Targets:"
 	@echo "  make run    - Alias for make dev"
 	@echo "  make dev    - Build and run server (CONFIG=$(CONFIG))"
-	@echo "  make generate-config - Write default config to $(CONFIG)"
+	@echo "  make config - Write default config to $(CONFIG) and generate sibling config.key if missing"
 	@echo "  make build  - Build Svelte UI and binary to $(BIN)"
 	@echo "  make test   - Run all Go tests with timeout and shuffle"
 	@echo "  make test-race - Run all Go tests with race detector and timeout"
@@ -22,8 +22,12 @@ run: dev
 dev: build
 	$(BIN) server --config $(CONFIG)
 
-generate-config:
+config:
-	go run $(CMD_DIR) generate-config > $(CONFIG)
+	mkdir -p "$(dir $(CONFIG))"
+	go run $(CMD_DIR) generate-config > "$(CONFIG)"
+	@if [ ! -f "$(dir $(CONFIG))config.key" ]; then \
+		go run $(CMD_DIR) generate-key > "$(dir $(CONFIG))config.key"; \
+	fi
 
 build: clean
 	npm --prefix ./web/ui run build

README.md

@@ -2,17 +2,20 @@
 
 Scratchbox is a minimal self-hosted scratch service written in Go. It is intentionally unauthenticated and optimized for temporary sharing of text or small files with an expiration time.
 
-Each upload creates exactly one scratch. For multi-file sharing, bundle files into an archive (for example `.zip` or `.tar.gz`) and upload that single archive file.
+For multi-file sharing, bundle files into an archive (for example `.zip` or `.tar.gz`) before upload.
-Scratch content is stored on disk gzip-compressed transparently to reduce filesystem usage; API/UI reads return original uncompressed content.
+Scratch content is gzip-compressed and AES-encrypted on disk transparently; API/UI reads return original uncompressed content.
 
 ## Quick Start
 
 1. Generate defaults directly:
    - `go run ./cmd/scratchbox generate-config > config.yaml`
-2. Adjust settings for your environment.
+2. Generate an encryption key file next to the config:
-3. Start the server:
+   - `go run ./cmd/scratchbox generate-key > config.key`
+   - or: `openssl rand -base64 32 > config.key`
+3. Adjust settings for your environment.
+4. Start the server:
    - `go run ./cmd/scratchbox server --config config.yaml`
-4. Open:
+5. Open:
    - `http://127.0.0.1:8080/`
 
 Without `--config`, built-in defaults are used.
@@ -43,6 +46,16 @@ All configuration is YAML.
 - `max_header_bytes`: max HTTP header size in bytes.
   - Must be `> 0`
   - Default: `1048576` (1 MiB)
+- `access_log`: structured request logs.
+  - `enabled`: enable HTTP access logs
+    - Default: `true`
+  - `file_path`: optional log file path
+    - When set, logs are tee'd to both stdout and the file
+  - `max_size`: rotation threshold for `file_path`
+    - Supported units: `B`, `KB`, `MB`, `GB`, `KiB`, `MiB`, `GiB`
+    - Default: `100MiB`
+  - `max_backups`: number of rotated files to retain
+    - Default: `5`
 
 ### `limits`
 
@@ -53,7 +66,7 @@ All configuration is YAML.
   - Default: `100MiB`
 - `default_ttl`: expiration applied to new scratches.
   - Must be `> 0` and `<= 24h`
-  - Default: `1h`
+  - Default: `15m`
 - `raw_cache_max_size`: max total decompressed bytes cached in memory for `/api/raw` range requests.
   - Supported units: `B`, `KB`, `MB`, `GB`, `KiB`, `MiB`, `GiB` (case-insensitive)
   - Must be `> 0`
@@ -70,6 +83,12 @@ All configuration is YAML.
 - `cleanup_interval`: background interval for deleting expired content.
   - Must be at least `10s`
   - Default: `1m`
+- `encryption_key_file`: path to a file containing a base64-encoded 32-byte key used for at-rest encryption.
+  - Relative paths are resolved from the config file directory
+  - Default: `config.key` (expected alongside `config.yaml`)
+  - Keep this key stable across restarts
+  - Changing the key makes existing scratch files unreadable
+  - `generate-key` emits a fresh random key each run
 
 ### `security`
 
@@ -84,14 +103,18 @@ All configuration is YAML.
 - `trusted_proxy_ips`: list of reverse-proxy IPs/CIDRs permitted to supply forwarded headers.
   - Required when `trust_proxy_headers: true`
   - Examples: `127.0.0.1`, `10.0.0.0/8`
-- `rate_limit.enabled`: enable per-IP token-bucket rate limiting on write and scratch-read routes (`POST /api/scratch`, `GET /api/scratch/{id}`, `GET /s/{id}`, `GET /api/raw/{id}`).
+- `rate_limit_ui`: per-IP token-bucket for UI routes (`GET /`, `GET /u`, `GET /s/{id}`).
-  - Default: `true`
+  - `enabled` default: `false`
-- `rate_limit.requests_per_minute`: steady refill rate per client IP.
+  - `requests_per_minute` must be `> 0` (default `360`)
-  - Must be `> 0`
+  - `burst` must be `> 0` (default `120`)
-  - Default: `30`
+- `rate_limit_api_read`: per-IP token-bucket for API read routes (`GET /api/config`, `GET /api/scratch/{id}`, `GET /api/raw/{id}`).
-- `rate_limit.burst`: immediate burst capacity per client IP.
+  - `enabled` default: `false`
-  - Must be `> 0`
+  - `requests_per_minute` must be `> 0` (default `300`)
-  - Default: `10`
+  - `burst` must be `> 0` (default `100`)
+- `rate_limit_api_write`: per-IP token-bucket for API write route (`POST /api/scratch`).
+  - `enabled` default: `true`
+  - `requests_per_minute` must be `> 0` (default `30`)
+  - `burst` must be `> 0` (default `10`)
 
 ## Security Posture
 
@@ -129,3 +152,5 @@ Scratchbox storage is designed for a single process instance per `storage.data_d
 
 - Do not run multiple scratchbox processes against the same data directory.
 - Metadata/index writes are process-local and are not coordinated with cross-process locking.
+- Scratch payload files and metadata index are encrypted at rest.
+- Scratch IDs are derived from the SHA-256 of the stored blob (encrypted+gzip payload on disk).

cmd/scratchbox/access_log_writer.go

@@ -0,0 +1,141 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"scratchbox/internal/config"
+)
+
+func newAccessLogWriter(cfg config.Config) (io.Writer, func() error, error) {
+	if !cfg.Server.AccessLog.Enabled {
+		return io.Discard, func() error { return nil }, nil
+	}
+	if cfg.Server.AccessLog.FilePath == "" {
+		return os.Stdout, func() error { return nil }, nil
+	}
+
+	writer, err := newRollingFileWriter(
+		cfg.Server.AccessLog.FilePath,
+		cfg.Server.AccessLog.MaxSizeBytes,
+		cfg.Server.AccessLog.MaxBackups,
+	)
+	if err != nil {
+		return nil, nil, err
+	}
+	return io.MultiWriter(os.Stdout, writer), writer.Close, nil
+}
+
+type rollingFileWriter struct {
+	mu         sync.Mutex
+	path       string
+	maxSize    int64
+	maxBackups int
+	file       *os.File
+	size       int64
+}
+
+func newRollingFileWriter(path string, maxSize int64, maxBackups int) (*rollingFileWriter, error) {
+	if maxSize <= 0 {
+		return nil, fmt.Errorf("max size must be > 0")
+	}
+	if maxBackups <= 0 {
+		return nil, fmt.Errorf("max backups must be > 0")
+	}
+
+	if dir := filepath.Dir(path); dir != "" && dir != "." {
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			return nil, fmt.Errorf("create log directory: %w", err)
+		}
+	}
+
+	f, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
+	if err != nil {
+		return nil, fmt.Errorf("open log file: %w", err)
+	}
+	info, err := f.Stat()
+	if err != nil {
+		_ = f.Close()
+		return nil, fmt.Errorf("stat log file: %w", err)
+	}
+
+	return &rollingFileWriter{
+		path:       path,
+		maxSize:    maxSize,
+		maxBackups: maxBackups,
+		file:       f,
+		size:       info.Size(),
+	}, nil
+}
+
+func (w *rollingFileWriter) Write(p []byte) (int, error) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	if w.size > 0 && w.size+int64(len(p)) > w.maxSize {
+		if err := w.rotateLocked(); err != nil {
+			return 0, err
+		}
+	}
+
+	n, err := w.file.Write(p)
+	w.size += int64(n)
+	return n, err
+}
+
+func (w *rollingFileWriter) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if w.file == nil {
+		return nil
+	}
+	err := w.file.Close()
+	w.file = nil
+	return err
+}
+
+func (w *rollingFileWriter) rotateLocked() error {
+	if err := w.file.Close(); err != nil {
+		return fmt.Errorf("close before rotate: %w", err)
+	}
+
+	for i := w.maxBackups - 1; i >= 1; i-- {
+		from := rotatedLogPath(w.path, i)
+		to := rotatedLogPath(w.path, i+1)
+		if _, err := os.Stat(from); err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+			return fmt.Errorf("stat rotated file %s: %w", from, err)
+		}
+		_ = os.Remove(to)
+		if err := os.Rename(from, to); err != nil {
+			return fmt.Errorf("rotate backup %s -> %s: %w", from, to, err)
+		}
+	}
+
+	firstBackup := rotatedLogPath(w.path, 1)
+	_ = os.Remove(firstBackup)
+	if _, err := os.Stat(w.path); err == nil {
+		if err := os.Rename(w.path, firstBackup); err != nil {
+			return fmt.Errorf("rotate current log to %s: %w", firstBackup, err)
+		}
+	} else if !os.IsNotExist(err) {
+		return fmt.Errorf("stat current log file: %w", err)
+	}
+
+	f, err := os.OpenFile(w.path, os.O_TRUNC|os.O_CREATE|os.O_WRONLY, 0o644)
+	if err != nil {
+		return fmt.Errorf("open rotated log file: %w", err)
+	}
+	w.file = f
+	w.size = 0
+	return nil
+}
+
+func rotatedLogPath(path string, index int) string {
+	return fmt.Sprintf("%s.%d", path, index)
+}

cmd/scratchbox/access_log_writer_test.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"scratchbox/internal/config"
+)
+
+func TestNewAccessLogWriterDisabled(t *testing.T) {
+	t.Parallel()
+
+	cfg := config.Default()
+	cfg.Server.AccessLog.Enabled = false
+	writer, closeFn, err := newAccessLogWriter(cfg)
+	if err != nil {
+		t.Fatalf("newAccessLogWriter() error = %v", err)
+	}
+	if writer == nil {
+		t.Fatalf("newAccessLogWriter() writer = nil")
+	}
+	if err := closeFn(); err != nil {
+		t.Fatalf("closeFn() error = %v", err)
+	}
+}
+
+func TestRollingFileWriterRotatesAndKeepsBackups(t *testing.T) {
+	t.Parallel()
+
+	logPath := filepath.Join(t.TempDir(), "access.log")
+	w, err := newRollingFileWriter(logPath, 10, 2)
+	if err != nil {
+		t.Fatalf("newRollingFileWriter() error = %v", err)
+	}
+	defer w.Close()
+
+	_, _ = w.Write([]byte("12345"))
+	_, _ = w.Write([]byte("67890"))
+	_, _ = w.Write([]byte("abc"))
+	_, _ = w.Write([]byte("defghijkl"))
+
+	if err := w.Close(); err != nil {
+		t.Fatalf("Close() error = %v", err)
+	}
+
+	current, err := os.ReadFile(logPath)
+	if err != nil {
+		t.Fatalf("ReadFile(current) error = %v", err)
+	}
+	backup1, err := os.ReadFile(logPath + ".1")
+	if err != nil {
+		t.Fatalf("ReadFile(backup1) error = %v", err)
+	}
+	backup2, err := os.ReadFile(logPath + ".2")
+	if err != nil {
+		t.Fatalf("ReadFile(backup2) error = %v", err)
+	}
+	if !bytes.Equal(current, []byte("defghijkl")) {
+		t.Fatalf("current log = %q, want %q", string(current), "defghijkl")
+	}
+	if !bytes.Equal(backup1, []byte("abc")) {
+		t.Fatalf("backup1 log = %q, want %q", string(backup1), "abc")
+	}
+	if !bytes.Equal(backup2, []byte("1234567890")) {
+		t.Fatalf("backup2 log = %q, want %q", string(backup2), "1234567890")
+	}
+}

cmd/scratchbox/generate_key.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	"scratchbox/internal/config"
+)
+
+func newGenerateKeyCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "generate-key",
+		Short: "Print a random base64 encryption key to stdout",
+		Args:  cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return writeEncryptionKey(cmd)
+		},
+	}
+	return cmd
+}
+
+func writeEncryptionKey(cmd *cobra.Command) error {
+	key, err := config.GenerateEncryptionKey()
+	if err != nil {
+		return fmt.Errorf("generate encryption key: %w", err)
+	}
+	if _, err := fmt.Fprintln(cmd.OutOrStdout(), key); err != nil {
+		return fmt.Errorf("write encryption key: %w", err)
+	}
+	return nil
+}

cmd/scratchbox/main.go

@@ -27,5 +27,6 @@ func newRootCmd() *cobra.Command {
 	}
 	cmd.AddCommand(newServerCmd())
 	cmd.AddCommand(newGenerateConfigCmd())
+	cmd.AddCommand(newGenerateKeyCmd())
 	return cmd
 }

cmd/scratchbox/main_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"io"
 	"log"
@@ -31,6 +32,18 @@ func repoRoot(t *testing.T) string {
 	return filepath.Clean(filepath.Join(filepath.Dir(file), "..", ".."))
 }
 
+func writeConfigKeyFile(t *testing.T, configPath string) {
+	t.Helper()
+	keyPath := filepath.Join(filepath.Dir(configPath), "config.key")
+	key, err := config.GenerateEncryptionKey()
+	if err != nil {
+		t.Fatalf("GenerateEncryptionKey() error = %v", err)
+	}
+	if err := os.WriteFile(keyPath, []byte(key+"\n"), 0o600); err != nil {
+		t.Fatalf("WriteFile(config.key) error = %v", err)
+	}
+}
+
 func TestMainProcessSuccess(t *testing.T) {
 	t.Parallel()
 
@@ -48,7 +61,15 @@ storage:
 security:
   allowed_ips: []
   trust_proxy_headers: false
-  rate_limit:
+  rate_limit_ui:
+    enabled: true
+    requests_per_minute: 10
+    burst: 1
+  rate_limit_api_read:
+    enabled: true
+    requests_per_minute: 10
+    burst: 1
+  rate_limit_api_write:
     enabled: true
     requests_per_minute: 10
     burst: 1
@@ -56,6 +77,7 @@ security:
 	if err := os.WriteFile(cfgPath, []byte(cfg), 0o644); err != nil {
 		t.Fatalf("WriteFile() error = %v", err)
 	}
+	writeConfigKeyFile(t, cfgPath)
 
 	cmd := exec.Command(os.Args[0], "-test.run=TestMainHelperProcess")
 	cmd.Dir = repoRoot(t)
@@ -104,7 +126,15 @@ storage:
 security:
   allowed_ips: []
   trust_proxy_headers: false
-  rate_limit:
+  rate_limit_ui:
+    enabled: true
+    requests_per_minute: 10
+    burst: 1
+  rate_limit_api_read:
+    enabled: true
+    requests_per_minute: 10
+    burst: 1
+  rate_limit_api_write:
     enabled: true
     requests_per_minute: 10
     burst: 1
@@ -112,6 +142,7 @@ security:
 	if err := os.WriteFile(cfgPath, []byte(cfg), 0o644); err != nil {
 		t.Fatalf("WriteFile() error = %v", err)
 	}
+	writeConfigKeyFile(t, cfgPath)
 
 	cmd := exec.Command(os.Args[0], "-test.run=TestMainHelperProcess")
 	cmd.Dir = repoRoot(t)
@@ -198,8 +229,26 @@ func TestGenerateConfigCommandWritesDefaultYAML(t *testing.T) {
 	if cfg.Storage.DataDir != "./data" {
 		t.Fatalf("storage.data_dir = %q, want %q", cfg.Storage.DataDir, "./data")
 	}
-	if cfg.Security.RateLimit.RequestsPerMinute != 30 {
+	if cfg.Storage.EncryptionKeyFile != "config.key" {
-		t.Fatalf("security.rate_limit.requests_per_minute = %d, want %d", cfg.Security.RateLimit.RequestsPerMinute, 30)
+		t.Fatalf("storage.encryption_key_file = %q, want %q", cfg.Storage.EncryptionKeyFile, "config.key")
+	}
+	if cfg.Security.RateLimitUI.RequestsPerMinute != 360 {
+		t.Fatalf("security.rate_limit_ui.requests_per_minute = %d, want %d", cfg.Security.RateLimitUI.RequestsPerMinute, 360)
+	}
+	if cfg.Security.RateLimitUI.Enabled {
+		t.Fatalf("security.rate_limit_ui.enabled = %v, want false", cfg.Security.RateLimitUI.Enabled)
+	}
+	if cfg.Security.RateLimitAPIRead.RequestsPerMinute != 300 {
+		t.Fatalf("security.rate_limit_api_read.requests_per_minute = %d, want %d", cfg.Security.RateLimitAPIRead.RequestsPerMinute, 300)
+	}
+	if cfg.Security.RateLimitAPIRead.Enabled {
+		t.Fatalf("security.rate_limit_api_read.enabled = %v, want false", cfg.Security.RateLimitAPIRead.Enabled)
+	}
+	if cfg.Security.RateLimitAPIWrite.RequestsPerMinute != 30 {
+		t.Fatalf("security.rate_limit_api_write.requests_per_minute = %d, want %d", cfg.Security.RateLimitAPIWrite.RequestsPerMinute, 30)
+	}
+	if !cfg.Security.RateLimitAPIWrite.Enabled {
+		t.Fatalf("security.rate_limit_api_write.enabled = %v, want true", cfg.Security.RateLimitAPIWrite.Enabled)
 	}
 }
 
@@ -216,6 +265,45 @@ func TestGenerateConfigCommandRejectsUnexpectedArgs(t *testing.T) {
 	}
 }
 
+func TestGenerateKeyCommandWritesKey(t *testing.T) {
+	t.Parallel()
+
+	cmd := newRootCmd()
+	var out bytes.Buffer
+	cmd.SetOut(&out)
+	cmd.SetErr(io.Discard)
+	cmd.SetArgs([]string{"generate-key"})
+
+	if err := cmd.Execute(); err != nil {
+		t.Fatalf("Execute() error = %v", err)
+	}
+
+	raw := strings.TrimSpace(out.String())
+	if raw == "" {
+		t.Fatalf("generate-key output is empty")
+	}
+	keyBytes, err := base64.StdEncoding.DecodeString(raw)
+	if err != nil {
+		t.Fatalf("generate-key output is not valid base64: %v", err)
+	}
+	if len(keyBytes) != 32 {
+		t.Fatalf("decoded key length = %d, want 32", len(keyBytes))
+	}
+}
+
+func TestGenerateKeyCommandRejectsUnexpectedArgs(t *testing.T) {
+	t.Parallel()
+
+	cmd := newRootCmd()
+	cmd.SetOut(io.Discard)
+	cmd.SetErr(io.Discard)
+	cmd.SetArgs([]string{"generate-key", "extra"})
+
+	if err := cmd.Execute(); err == nil {
+		t.Fatalf("expected error for unexpected args")
+	}
+}
+
 func TestLiveServerEndToEndHTTP(t *testing.T) {
 	tmp := t.TempDir()
 	cfgPath := filepath.Join(tmp, "config.yaml")
@@ -231,7 +319,15 @@ storage:
 security:
   allowed_ips: []
   trust_proxy_headers: false
-  rate_limit:
+  rate_limit_ui:
+    enabled: true
+    requests_per_minute: 30
+    burst: 10
+  rate_limit_api_read:
+    enabled: true
+    requests_per_minute: 30
+    burst: 10
+  rate_limit_api_write:
     enabled: true
     requests_per_minute: 30
     burst: 10
@@ -239,13 +335,14 @@ security:
 	if err := os.WriteFile(cfgPath, []byte(cfgRaw), 0o644); err != nil {
 		t.Fatalf("WriteFile() error = %v", err)
 	}
+	writeConfigKeyFile(t, cfgPath)
 
 	cfg, err := config.Load(cfgPath)
 	if err != nil {
 		t.Fatalf("config.Load() error = %v", err)
 	}
 	logger := log.New(io.Discard, "", 0)
-	store, err := storage.NewFilesystemStore(cfg.Storage.DataDir)
+	store, err := storage.NewFilesystemStore(cfg.Storage.DataDir, cfg.Storage.EncryptionKeyBytes)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -261,7 +358,7 @@ security:
 		_ = os.Chdir(wd)
 	}()
 
-	srv, err := httpapi.NewServer(cfg, store, logger)
+	srv, err := httpapi.NewServer(cfg, store, logger, logger)
 	if err != nil {
 		t.Fatalf("httpapi.NewServer() error = %v", err)
 	}

cmd/scratchbox/server.go

@@ -40,13 +40,30 @@ func run(configPath string) error {
 	}
 
 	logger := log.New(os.Stdout, "[scratchbox] ", log.LstdFlags|log.LUTC)
+	accessWriter, closeAccessWriter, err := newAccessLogWriter(cfg)
+	if err != nil {
+		return fmt.Errorf("access log init failed: %w", err)
+	}
+	defer func() {
+		if closeErr := closeAccessWriter(); closeErr != nil {
+			logger.Printf("access log writer close failed: %v", closeErr)
+		}
+	}()
+	var accessLogger *log.Logger
+	if cfg.Server.AccessLog.Enabled {
+		accessLogger = log.New(accessWriter, "[access] ", log.LstdFlags|log.LUTC)
+	}
 
-	store, err := storage.NewFilesystemStore(cfg.Storage.DataDir)
+	store, err := storage.NewFilesystemStoreWithDefaultTTL(
+		cfg.Storage.DataDir,
+		cfg.Limits.DefaultTTLDuration,
+		cfg.Storage.EncryptionKeyBytes,
+	)
 	if err != nil {
 		return fmt.Errorf("storage init failed: %w", err)
 	}
 
-	server, err := httpapi.NewServer(cfg, store, logger)
+	server, err := httpapi.NewServer(cfg, store, logger, accessLogger)
 	if err != nil {
 		return fmt.Errorf("http init failed: %w", err)
 	}

internal/cleanup/worker_test.go

@@ -12,10 +12,12 @@ import (
 	"scratchbox/internal/storage"
 )
 
+var testStorageKey = []byte("0123456789abcdef0123456789abcdef")
+
 func TestNewWorker(t *testing.T) {
 	t.Parallel()
 
-	store, err := storage.NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := storage.NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testStorageKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -29,7 +31,7 @@ func TestNewWorker(t *testing.T) {
 func TestWorkerStartRemovesExpiredAndLogs(t *testing.T) {
 	t.Parallel()
 
-	store, err := storage.NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := storage.NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testStorageKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -53,7 +55,7 @@ func TestWorkerStartRemovesExpiredAndLogs(t *testing.T) {
 func TestWorkerStartWithNoExpiredEntries(t *testing.T) {
 	t.Parallel()
 
-	store, err := storage.NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := storage.NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testStorageKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}

internal/config/config.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	"crypto/rand"
+	"encoding/base64"
 	"errors"
 	"fmt"
 	"net/netip"
@@ -14,23 +16,34 @@ import (
 )
 
 const (
-	defaultListenAddr         = ":8080"
+	defaultListenAddr                = ":8080"
-	defaultReadHeaderTimeout  = "5s"
+	defaultReadHeaderTimeout         = "5s"
-	defaultReadTimeout        = "30s"
+	defaultReadTimeout               = "30s"
-	defaultWriteTimeout       = "30s"
+	defaultWriteTimeout              = "30s"
-	defaultIdleTimeout        = "120s"
+	defaultIdleTimeout               = "120s"
-	defaultMaxHeaderBytes     = 1 << 20
+	defaultMaxHeaderBytes            = 1 << 20
-	defaultMaxUploadSize      = "100MiB"
+	defaultAccessLogEnabled          = true
-	defaultTTL                = "1h"
+	defaultAccessLogMaxSize          = "100MiB"
-	defaultRawCacheMaxSize    = "200MiB"
+	defaultAccessLogMaxBackups       = 5
-	defaultRawCacheMaxEntries = 32
+	defaultMaxUploadSize             = "100MiB"
-	defaultDataDir            = "./data"
+	defaultTTL                       = "15m"
-	defaultCleanupInterval    = "1m"
+	defaultRawCacheMaxSize           = "200MiB"
-	defaultRateLimitEnabled   = true
+	defaultRawCacheMaxEntries        = 32
-	defaultRequestsPerMinute  = 30
+	defaultDataDir                   = "./data"
-	defaultRateLimitBurst     = 10
+	defaultCleanupInterval           = "1m"
-	maxDefaultTTLLimit        = 24 * time.Hour
+	defaultStorageEncryptionKey      = "vVPlqMfKa8OtD3x0RKp4rVCJ4QoScf5mWdgfg4f+5GU="
-	minCleanupInterval        = 10 * time.Second
+	defaultEncryptionKeyFile         = "config.key"
+	defaultUIRateLimitEnabled        = false
+	defaultAPIReadRateLimitEnabled   = false
+	defaultAPIWriteRateLimitEnabled  = true
+	defaultUIRequestsPerMinute       = 360
+	defaultUIRateLimitBurst          = 120
+	defaultAPIReadRequestsPerMinute  = 300
+	defaultAPIReadRateLimitBurst     = 100
+	defaultAPIWriteRequestsPerMinute = 30
+	defaultAPIWriteRateLimitBurst    = 10
+	maxDefaultTTLLimit               = 24 * time.Hour
+	minCleanupInterval               = 10 * time.Second
 )
 
 type Config struct {
@@ -41,16 +54,25 @@ type Config struct {
 }
 
 type ServerConfig struct {
-	ListenAddr           string        `yaml:"listen_addr" comment:"Address to bind the HTTP server to."`
+	ListenAddr           string          `yaml:"listen_addr" comment:"Address to bind the HTTP server to."`
-	ReadHeaderTimeout    string        `yaml:"read_header_timeout" comment:"Maximum duration for reading request headers (for slowloris protection). Must be > 0."`
+	ReadHeaderTimeout    string          `yaml:"read_header_timeout" comment:"Maximum duration for reading request headers (for slowloris protection). Must be > 0."`
-	ReadTimeout          string        `yaml:"read_timeout" comment:"Maximum duration for reading the full request, including body. Must be > 0."`
+	ReadTimeout          string          `yaml:"read_timeout" comment:"Maximum duration for reading the full request, including body. Must be > 0."`
-	WriteTimeout         string        `yaml:"write_timeout" comment:"Maximum duration before timing out writes of a response. Must be > 0."`
+	WriteTimeout         string          `yaml:"write_timeout" comment:"Maximum duration before timing out writes of a response. Must be > 0."`
-	IdleTimeout          string        `yaml:"idle_timeout" comment:"Maximum amount of time to wait for the next request when keep-alives are enabled. Must be > 0."`
+	IdleTimeout          string          `yaml:"idle_timeout" comment:"Maximum amount of time to wait for the next request when keep-alives are enabled. Must be > 0."`
-	MaxHeaderBytes       int           `yaml:"max_header_bytes" comment:"Maximum size of request headers in bytes. Must be > 0."`
+	MaxHeaderBytes       int             `yaml:"max_header_bytes" comment:"Maximum size of request headers in bytes. Must be > 0."`
-	ReadHeaderTimeoutDur time.Duration `yaml:"-"`
+	AccessLog            AccessLogConfig `yaml:"access_log" comment:"Access log settings for all HTTP requests."`
-	ReadTimeoutDur       time.Duration `yaml:"-"`
+	ReadHeaderTimeoutDur time.Duration   `yaml:"-"`
-	WriteTimeoutDur      time.Duration `yaml:"-"`
+	ReadTimeoutDur       time.Duration   `yaml:"-"`
-	IdleTimeoutDur       time.Duration `yaml:"-"`
+	WriteTimeoutDur      time.Duration   `yaml:"-"`
+	IdleTimeoutDur       time.Duration   `yaml:"-"`
+}
+
+type AccessLogConfig struct {
+	Enabled      bool   `yaml:"enabled" comment:"Enable HTTP access logs."`
+	FilePath     string `yaml:"file_path" comment:"Optional file path for access logs. When set, logs are tee'd to stdout and this file."`
+	MaxSize      string `yaml:"max_size" comment:"Maximum size for access log file before rotation. Supports B, KB, MB, GB and KiB, MiB, GiB."`
+	MaxBackups   int    `yaml:"max_backups" comment:"Number of rotated access log files to keep."`
+	MaxSizeBytes int64  `yaml:"-"`
 }
 
 type LimitsConfig struct {
@@ -66,14 +88,18 @@ type LimitsConfig struct {
 type StorageConfig struct {
 	DataDir               string        `yaml:"data_dir" comment:"Directory where scratch files and metadata are stored."`
 	CleanupInterval       string        `yaml:"cleanup_interval" comment:"How often expired scratches are deleted (minimum 10s)."`
+	EncryptionKeyFile     string        `yaml:"encryption_key_file" comment:"Path to a file containing a base64-encoded 32-byte AES key for at-rest encryption. Relative paths are resolved from the config file directory."`
 	CleanupIntervalParsed time.Duration `yaml:"-"`
+	EncryptionKeyBytes    []byte        `yaml:"-"`
 }
 
 type SecurityConfig struct {
 	AllowedIPs           []string        `yaml:"allowed_ips" comment:"Allowlist for POST /api/scratch as IPs or CIDRs (examples: 127.0.0.1, 192.168.1.0/24). Keep 127.0.0.1 for local access; add trusted ranges as needed. Empty means unrestricted."`
 	TrustProxyHeaders    bool            `yaml:"trust_proxy_headers" comment:"Honor X-Forwarded-For / X-Real-IP only when request source IP matches security.trusted_proxy_ips."`
 	TrustedProxyIPs      []string        `yaml:"trusted_proxy_ips" comment:"IPs/CIDRs of reverse proxies allowed to supply forwarded client IP headers. Required when trust_proxy_headers is true."`
-	RateLimit            RateLimitConfig `yaml:"rate_limit" comment:"Per-client token bucket on write and scratch read routes."`
+	RateLimitUI          RateLimitConfig `yaml:"rate_limit_ui" comment:"Per-client token bucket on UI routes (/, /u, /s/{id})."`
+	RateLimitAPIRead     RateLimitConfig `yaml:"rate_limit_api_read" comment:"Per-client token bucket on API read routes (GET /api/config, GET /api/scratch/{id}, GET /api/raw/{id})."`
+	RateLimitAPIWrite    RateLimitConfig `yaml:"rate_limit_api_write" comment:"Per-client token bucket on API write route (POST /api/scratch)."`
 	AllowedPrefixes      []netip.Prefix  `yaml:"-"`
 	TrustedProxyPrefixes []netip.Prefix  `yaml:"-"`
 }
@@ -95,6 +121,9 @@ func Load(path string) (Config, error) {
 			return Config{}, fmt.Errorf("parse config yaml: %w", err)
 		}
 	}
+	if err := cfg.loadEncryptionKey(path); err != nil {
+		return Config{}, err
+	}
 
 	if err := cfg.Validate(); err != nil {
 		return Config{}, err
@@ -115,6 +144,11 @@ func defaults() Config {
 			WriteTimeout:      defaultWriteTimeout,
 			IdleTimeout:       defaultIdleTimeout,
 			MaxHeaderBytes:    defaultMaxHeaderBytes,
+			AccessLog: AccessLogConfig{
+				Enabled:    defaultAccessLogEnabled,
+				MaxSize:    defaultAccessLogMaxSize,
+				MaxBackups: defaultAccessLogMaxBackups,
+			},
 		},
 		Limits: LimitsConfig{
 			MaxUploadSize:      defaultMaxUploadSize,
@@ -123,17 +157,29 @@ func defaults() Config {
 			RawCacheMaxEntries: defaultRawCacheMaxEntries,
 		},
 		Storage: StorageConfig{
-			DataDir:         defaultDataDir,
+			DataDir:            defaultDataDir,
-			CleanupInterval: defaultCleanupInterval,
+			CleanupInterval:    defaultCleanupInterval,
+			EncryptionKeyFile:  defaultEncryptionKeyFile,
+			EncryptionKeyBytes: mustDecodeDefaultEncryptionKey(),
 		},
 		Security: SecurityConfig{
 			AllowedIPs: []string{
 				"127.0.0.1",
 			},
-			RateLimit: RateLimitConfig{
+			RateLimitUI: RateLimitConfig{
-				Enabled:           defaultRateLimitEnabled,
+				Enabled:           defaultUIRateLimitEnabled,
-				RequestsPerMinute: defaultRequestsPerMinute,
+				RequestsPerMinute: defaultUIRequestsPerMinute,
-				Burst:             defaultRateLimitBurst,
+				Burst:             defaultUIRateLimitBurst,
+			},
+			RateLimitAPIRead: RateLimitConfig{
+				Enabled:           defaultAPIReadRateLimitEnabled,
+				RequestsPerMinute: defaultAPIReadRequestsPerMinute,
+				Burst:             defaultAPIReadRateLimitBurst,
+			},
+			RateLimitAPIWrite: RateLimitConfig{
+				Enabled:           defaultAPIWriteRateLimitEnabled,
+				RequestsPerMinute: defaultAPIWriteRequestsPerMinute,
+				Burst:             defaultAPIWriteRateLimitBurst,
 			},
 		},
 	}
@@ -182,6 +228,14 @@ func (c *Config) Validate() error {
 	if c.Server.MaxHeaderBytes <= 0 {
 		return errors.New("server.max_header_bytes must be > 0")
 	}
+	accessLogMaxSizeBytes, err := parseHumanSize(c.Server.AccessLog.MaxSize)
+	if err != nil {
+		return fmt.Errorf("server.access_log.max_size invalid: %w", err)
+	}
+	c.Server.AccessLog.MaxSizeBytes = accessLogMaxSizeBytes
+	if c.Server.AccessLog.MaxBackups <= 0 {
+		return errors.New("server.access_log.max_backups must be > 0")
+	}
 
 	sizeBytes, err := parseHumanSize(c.Limits.MaxUploadSize)
 	if err != nil {
@@ -222,6 +276,12 @@ func (c *Config) Validate() error {
 	if err := ensureWritableDir(c.Storage.DataDir); err != nil {
 		return fmt.Errorf("storage.data_dir not writable: %w", err)
 	}
+	if strings.TrimSpace(c.Storage.EncryptionKeyFile) == "" {
+		return errors.New("storage.encryption_key_file is required")
+	}
+	if len(c.Storage.EncryptionKeyBytes) != 32 {
+		return fmt.Errorf("storage.encryption_key_file must decode to 32 bytes, got %d", len(c.Storage.EncryptionKeyBytes))
+	}
 
 	prefixes, err := parseAllowedPrefixes(c.Security.AllowedIPs)
 	if err != nil {
@@ -237,11 +297,23 @@ func (c *Config) Validate() error {
 		return errors.New("security.trusted_proxy_ips is required when security.trust_proxy_headers is true")
 	}
 
-	if c.Security.RateLimit.RequestsPerMinute <= 0 {
+	if c.Security.RateLimitUI.RequestsPerMinute <= 0 {
-		return errors.New("security.rate_limit.requests_per_minute must be > 0")
+		return errors.New("security.rate_limit_ui.requests_per_minute must be > 0")
 	}
-	if c.Security.RateLimit.Burst <= 0 {
+	if c.Security.RateLimitUI.Burst <= 0 {
-		return errors.New("security.rate_limit.burst must be > 0")
+		return errors.New("security.rate_limit_ui.burst must be > 0")
+	}
+	if c.Security.RateLimitAPIRead.RequestsPerMinute <= 0 {
+		return errors.New("security.rate_limit_api_read.requests_per_minute must be > 0")
+	}
+	if c.Security.RateLimitAPIRead.Burst <= 0 {
+		return errors.New("security.rate_limit_api_read.burst must be > 0")
+	}
+	if c.Security.RateLimitAPIWrite.RequestsPerMinute <= 0 {
+		return errors.New("security.rate_limit_api_write.requests_per_minute must be > 0")
+	}
+	if c.Security.RateLimitAPIWrite.Burst <= 0 {
+		return errors.New("security.rate_limit_api_write.burst must be > 0")
 	}
 
 	return nil
@@ -338,3 +410,56 @@ func parseHumanSize(raw string) (int64, error) {
 	}
 	return size, nil
 }
+
+func GenerateEncryptionKey() (string, error) {
+	raw := make([]byte, 32)
+	if _, err := rand.Read(raw); err != nil {
+		return "", fmt.Errorf("generate encryption key bytes: %w", err)
+	}
+	return base64.StdEncoding.EncodeToString(raw), nil
+}
+
+func (c *Config) loadEncryptionKey(configPath string) error {
+	if configPath == "" {
+		return nil
+	}
+	keyPath := strings.TrimSpace(c.Storage.EncryptionKeyFile)
+	if keyPath == "" {
+		return errors.New("storage.encryption_key_file is required")
+	}
+	if !filepath.IsAbs(keyPath) {
+		keyPath = filepath.Join(filepath.Dir(configPath), keyPath)
+	}
+	keyRaw, err := os.ReadFile(keyPath)
+	if err != nil {
+		return fmt.Errorf("read storage.encryption_key_file %q: %w", keyPath, err)
+	}
+	encKey, err := decodeEncryptionKey(strings.TrimSpace(string(keyRaw)))
+	if err != nil {
+		return fmt.Errorf("storage.encryption_key_file invalid: %w", err)
+	}
+	c.Storage.EncryptionKeyBytes = encKey
+	return nil
+}
+
+func decodeEncryptionKey(raw string) ([]byte, error) {
+	if raw == "" {
+		return nil, errors.New("key is empty")
+	}
+	encKey, err := base64.StdEncoding.DecodeString(raw)
+	if err != nil {
+		return nil, fmt.Errorf("invalid base64: %w", err)
+	}
+	if len(encKey) != 32 {
+		return nil, fmt.Errorf("must decode to 32 bytes, got %d", len(encKey))
+	}
+	return encKey, nil
+}
+
+func mustDecodeDefaultEncryptionKey() []byte {
+	encKey, err := decodeEncryptionKey(defaultStorageEncryptionKey)
+	if err != nil {
+		panic(fmt.Sprintf("invalid built-in encryption key: %v", err))
+	}
+	return encKey
+}

internal/config/config_test.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"encoding/base64"
 	"net/netip"
 	"os"
 	"path/filepath"
@@ -37,8 +38,17 @@ func TestValidateAppliesDefaultsAndParsedFields(t *testing.T) {
 	if cfg.Server.MaxHeaderBytes != 1<<20 {
 		t.Fatalf("MaxHeaderBytes = %d, want %d", cfg.Server.MaxHeaderBytes, 1<<20)
 	}
-	if cfg.Limits.DefaultTTLDuration != time.Hour {
+	if !cfg.Server.AccessLog.Enabled {
-		t.Fatalf("DefaultTTLDuration = %s, want 1h", cfg.Limits.DefaultTTLDuration)
+		t.Fatalf("AccessLog.Enabled = %v, want true", cfg.Server.AccessLog.Enabled)
+	}
+	if cfg.Server.AccessLog.MaxSizeBytes != 100*1024*1024 {
+		t.Fatalf("AccessLog.MaxSizeBytes = %d, want %d", cfg.Server.AccessLog.MaxSizeBytes, int64(100*1024*1024))
+	}
+	if cfg.Server.AccessLog.MaxBackups != 5 {
+		t.Fatalf("AccessLog.MaxBackups = %d, want 5", cfg.Server.AccessLog.MaxBackups)
+	}
+	if cfg.Limits.DefaultTTLDuration != 15*time.Minute {
+		t.Fatalf("DefaultTTLDuration = %s, want 15m", cfg.Limits.DefaultTTLDuration)
 	}
 	if cfg.Limits.RawCacheMaxBytes != 200*1024*1024 {
 		t.Fatalf("RawCacheMaxBytes = %d, want %d", cfg.Limits.RawCacheMaxBytes, int64(200*1024*1024))
@@ -49,6 +59,9 @@ func TestValidateAppliesDefaultsAndParsedFields(t *testing.T) {
 	if cfg.Storage.CleanupIntervalParsed != time.Minute {
 		t.Fatalf("CleanupIntervalParsed = %s, want 1m", cfg.Storage.CleanupIntervalParsed)
 	}
+	if len(cfg.Storage.EncryptionKeyBytes) != 32 {
+		t.Fatalf("EncryptionKeyBytes length = %d, want 32", len(cfg.Storage.EncryptionKeyBytes))
+	}
 	if len(cfg.Security.AllowedPrefixes) != 1 {
 		t.Fatalf("AllowedPrefixes len = %d, want 1", len(cfg.Security.AllowedPrefixes))
 	}
@@ -63,6 +76,7 @@ func TestLoadParsesConfiguredFields(t *testing.T) {
 	tmp := t.TempDir()
 	dataDir := filepath.Join(tmp, "store")
 	configPath := filepath.Join(tmp, "config.yaml")
+	keyPath := filepath.Join(tmp, "scratchbox.key")
 	content := `
 server:
   listen_addr: "127.0.0.1:9090"
@@ -71,6 +85,11 @@ server:
   write_timeout: "35s"
   idle_timeout: "90s"
   max_header_bytes: 2097152
+  access_log:
+    enabled: true
+    file_path: "` + filepath.Join(tmp, "access.log") + `"
+    max_size: "2MiB"
+    max_backups: 7
 limits:
   max_upload_size: "2MiB"
   default_ttl: "2h"
@@ -79,6 +98,7 @@ limits:
 storage:
   data_dir: "` + dataDir + `"
   cleanup_interval: "45s"
+  encryption_key_file: "` + filepath.Base(keyPath) + `"
 security:
   allowed_ips:
     - "127.0.0.1"
@@ -86,7 +106,15 @@ security:
   trust_proxy_headers: true
   trusted_proxy_ips:
     - "10.0.0.0/8"
-  rate_limit:
+  rate_limit_ui:
+    enabled: true
+    requests_per_minute: 12
+    burst: 4
+  rate_limit_api_read:
+    enabled: true
+    requests_per_minute: 12
+    burst: 4
+  rate_limit_api_write:
     enabled: true
     requests_per_minute: 12
     burst: 4
@@ -94,6 +122,9 @@ security:
 	if err := os.WriteFile(configPath, []byte(content), 0o644); err != nil {
 		t.Fatalf("WriteFile() error = %v", err)
 	}
+	if err := os.WriteFile(keyPath, []byte("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=\n"), 0o600); err != nil {
+		t.Fatalf("WriteFile(key) error = %v", err)
+	}
 
 	cfg, err := Load(configPath)
 	if err != nil {
@@ -118,6 +149,15 @@ security:
 	if cfg.Server.MaxHeaderBytes != 2*1024*1024 {
 		t.Fatalf("MaxHeaderBytes = %d, want %d", cfg.Server.MaxHeaderBytes, 2*1024*1024)
 	}
+	if !cfg.Server.AccessLog.Enabled {
+		t.Fatalf("AccessLog.Enabled = false, want true")
+	}
+	if cfg.Server.AccessLog.MaxSizeBytes != 2*1024*1024 {
+		t.Fatalf("AccessLog.MaxSizeBytes = %d, want %d", cfg.Server.AccessLog.MaxSizeBytes, int64(2*1024*1024))
+	}
+	if cfg.Server.AccessLog.MaxBackups != 7 {
+		t.Fatalf("AccessLog.MaxBackups = %d, want 7", cfg.Server.AccessLog.MaxBackups)
+	}
 	if cfg.Limits.MaxUploadSizeBytes != 2*1024*1024 {
 		t.Fatalf("MaxUploadSizeBytes = %d, want %d", cfg.Limits.MaxUploadSizeBytes, int64(2*1024*1024))
 	}
@@ -133,11 +173,23 @@ security:
 	if cfg.Storage.CleanupIntervalParsed != 45*time.Second {
 		t.Fatalf("CleanupIntervalParsed = %s, want 45s", cfg.Storage.CleanupIntervalParsed)
 	}
+	if len(cfg.Storage.EncryptionKeyBytes) != 32 {
+		t.Fatalf("EncryptionKeyBytes length = %d, want 32", len(cfg.Storage.EncryptionKeyBytes))
+	}
+	if cfg.Storage.EncryptionKeyBytes[0] != 0 {
+		t.Fatalf("EncryptionKeyBytes[0] = %d, want 0", cfg.Storage.EncryptionKeyBytes[0])
+	}
 	if !cfg.Security.TrustProxyHeaders {
 		t.Fatalf("TrustProxyHeaders = false, want true")
 	}
-	if cfg.Security.RateLimit.RequestsPerMinute != 12 || cfg.Security.RateLimit.Burst != 4 {
+	if cfg.Security.RateLimitUI.RequestsPerMinute != 12 || cfg.Security.RateLimitUI.Burst != 4 {
-		t.Fatalf("unexpected rate_limit values: %+v", cfg.Security.RateLimit)
+		t.Fatalf("unexpected rate_limit_ui values: %+v", cfg.Security.RateLimitUI)
+	}
+	if cfg.Security.RateLimitAPIRead.RequestsPerMinute != 12 || cfg.Security.RateLimitAPIRead.Burst != 4 {
+		t.Fatalf("unexpected rate_limit_api_read values: %+v", cfg.Security.RateLimitAPIRead)
+	}
+	if cfg.Security.RateLimitAPIWrite.RequestsPerMinute != 12 || cfg.Security.RateLimitAPIWrite.Burst != 4 {
+		t.Fatalf("unexpected rate_limit_api_write values: %+v", cfg.Security.RateLimitAPIWrite)
 	}
 	if len(cfg.Security.AllowedPrefixes) != 2 {
 		t.Fatalf("AllowedPrefixes len = %d, want 2", len(cfg.Security.AllowedPrefixes))
@@ -204,6 +256,20 @@ func TestValidateRejectsInvalidValues(t *testing.T) {
 			},
 			wantErr: "server.max_header_bytes",
 		},
+		{
+			name: "invalid access log max size",
+			mutate: func(cfg *Config) {
+				cfg.Server.AccessLog.MaxSize = "oops"
+			},
+			wantErr: "server.access_log.max_size",
+		},
+		{
+			name: "invalid access log max backups",
+			mutate: func(cfg *Config) {
+				cfg.Server.AccessLog.MaxBackups = 0
+			},
+			wantErr: "server.access_log.max_backups",
+		},
 		{
 			name: "invalid ttl parse",
 			mutate: func(cfg *Config) {
@@ -255,11 +321,25 @@ func TestValidateRejectsInvalidValues(t *testing.T) {
 			wantErr: "security.trusted_proxy_ips is required",
 		},
 		{
-			name: "invalid rate limit burst",
+			name: "invalid ui rate limit burst",
 			mutate: func(cfg *Config) {
-				cfg.Security.RateLimit.Burst = 0
+				cfg.Security.RateLimitUI.Burst = 0
 			},
-			wantErr: "security.rate_limit.burst",
+			wantErr: "security.rate_limit_ui.burst",
+		},
+		{
+			name: "invalid api read rate limit burst",
+			mutate: func(cfg *Config) {
+				cfg.Security.RateLimitAPIRead.Burst = 0
+			},
+			wantErr: "security.rate_limit_api_read.burst",
+		},
+		{
+			name: "invalid api write rate limit burst",
+			mutate: func(cfg *Config) {
+				cfg.Security.RateLimitAPIWrite.Burst = 0
+			},
+			wantErr: "security.rate_limit_api_write.burst",
 		},
 		{
 			name: "data dir required",
@@ -283,11 +363,39 @@ func TestValidateRejectsInvalidValues(t *testing.T) {
 			wantErr: "storage.cleanup_interval",
 		},
 		{
-			name: "invalid rate limit rpm",
+			name: "encryption key file required",
 			mutate: func(cfg *Config) {
-				cfg.Security.RateLimit.RequestsPerMinute = 0
+				cfg.Storage.EncryptionKeyFile = " "
 			},
-			wantErr: "security.rate_limit.requests_per_minute",
+			wantErr: "storage.encryption_key_file is required",
+		},
+		{
+			name: "encryption key bytes invalid length",
+			mutate: func(cfg *Config) {
+				cfg.Storage.EncryptionKeyBytes = []byte("short")
+			},
+			wantErr: "storage.encryption_key_file must decode to 32 bytes",
+		},
+		{
+			name: "invalid ui rate limit rpm",
+			mutate: func(cfg *Config) {
+				cfg.Security.RateLimitUI.RequestsPerMinute = 0
+			},
+			wantErr: "security.rate_limit_ui.requests_per_minute",
+		},
+		{
+			name: "invalid api read rate limit rpm",
+			mutate: func(cfg *Config) {
+				cfg.Security.RateLimitAPIRead.RequestsPerMinute = 0
+			},
+			wantErr: "security.rate_limit_api_read.requests_per_minute",
+		},
+		{
+			name: "invalid api write rate limit rpm",
+			mutate: func(cfg *Config) {
+				cfg.Security.RateLimitAPIWrite.RequestsPerMinute = 0
+			},
+			wantErr: "security.rate_limit_api_write.requests_per_minute",
 		},
 	}
 
@@ -328,6 +436,29 @@ func TestLoadErrors(t *testing.T) {
 	if err == nil || !strings.Contains(err.Error(), "parse config yaml") {
 		t.Fatalf("Load() error = %v, want yaml parse error", err)
 	}
+
+	validConfigPath := filepath.Join(tmp, "valid.yaml")
+	validConfig := `
+storage:
+  data_dir: "` + filepath.Join(tmp, "store") + `"
+  cleanup_interval: "10s"
+`
+	if err := os.WriteFile(validConfigPath, []byte(validConfig), 0o644); err != nil {
+		t.Fatalf("WriteFile(valid config) error = %v", err)
+	}
+	_, err = Load(validConfigPath)
+	if err == nil || !strings.Contains(err.Error(), "read storage.encryption_key_file") {
+		t.Fatalf("Load() error = %v, want missing key file error", err)
+	}
+
+	keyPath := filepath.Join(tmp, "config.key")
+	if err := os.WriteFile(keyPath, []byte("not-base64"), 0o600); err != nil {
+		t.Fatalf("WriteFile(invalid key) error = %v", err)
+	}
+	_, err = Load(validConfigPath)
+	if err == nil || !strings.Contains(err.Error(), "storage.encryption_key_file invalid: invalid base64") {
+		t.Fatalf("Load() error = %v, want invalid key base64 error", err)
+	}
 }
 
 func TestParseAllowedPrefixesTrimsAndParses(t *testing.T) {
@@ -385,3 +516,26 @@ func TestParseHumanSizeVariants(t *testing.T) {
 		})
 	}
 }
+
+func TestGenerateEncryptionKey(t *testing.T) {
+	t.Parallel()
+
+	k1, err := GenerateEncryptionKey()
+	if err != nil {
+		t.Fatalf("GenerateEncryptionKey() error = %v", err)
+	}
+	k2, err := GenerateEncryptionKey()
+	if err != nil {
+		t.Fatalf("GenerateEncryptionKey() second error = %v", err)
+	}
+	if k1 == k2 {
+		t.Fatalf("GenerateEncryptionKey() produced duplicate keys")
+	}
+	b1, err := base64.StdEncoding.DecodeString(k1)
+	if err != nil {
+		t.Fatalf("DecodeString(k1) error = %v", err)
+	}
+	if len(b1) != 32 {
+		t.Fatalf("decoded key length = %d, want 32", len(b1))
+	}
+}

internal/http/handlers.go

@@ -18,46 +18,63 @@ import (
 )
 
 type Server struct {
-	cfg      config.Config
+	cfg          config.Config
-	store    *storage.FilesystemStore
+	store        *storage.FilesystemStore
-	logger   *log.Logger
+	logger       *log.Logger
-	rawCache *rawContentCache
+	accessLogger *log.Logger
+	rawCache     *rawContentCache
 }
 
-func NewServer(cfg config.Config, store *storage.FilesystemStore, logger *log.Logger) (*Server, error) {
+func NewServer(cfg config.Config, store *storage.FilesystemStore, logger *log.Logger, accessLogger *log.Logger) (*Server, error) {
 	return &Server{
-		cfg:      cfg,
+		cfg:          cfg,
-		store:    store,
+		store:        store,
-		logger:   logger,
+		logger:       logger,
-		rawCache: newRawContentCache(cfg.Limits.RawCacheMaxEntries, cfg.Limits.RawCacheMaxBytes),
+		accessLogger: accessLogger,
+		rawCache:     newRawContentCache(cfg.Limits.RawCacheMaxEntries, cfg.Limits.RawCacheMaxBytes),
 	}, nil
 }
 
 func (s *Server) Routes() http.Handler {
 	mux := http.NewServeMux()
-	mux.Handle("GET /{$}", http.HandlerFunc(s.serveSPA))
+	uiMiddlewares := make([]func(http.Handler) http.Handler, 0, 1)
-	mux.Handle("GET /u", http.HandlerFunc(s.serveSPA))
+	apiReadMiddlewares := make([]func(http.Handler) http.Handler, 0, 1)
-	mux.Handle("GET /api/config", http.HandlerFunc(s.getUIConfig))
+	apiWriteMiddlewares := make([]func(http.Handler) http.Handler, 0, 1)
+	if s.cfg.Security.RateLimitUI.Enabled {
+		uiLimiter := NewRateLimiter(s.cfg.Security.RateLimitUI.RequestsPerMinute, s.cfg.Security.RateLimitUI.Burst)
+		uiMiddlewares = append(uiMiddlewares, RateLimitMiddleware(uiLimiter, s.cfg.Security.TrustProxyHeaders, s.cfg.Security.TrustedProxyPrefixes))
+	}
+	if s.cfg.Security.RateLimitAPIRead.Enabled {
+		apiReadLimiter := NewRateLimiter(s.cfg.Security.RateLimitAPIRead.RequestsPerMinute, s.cfg.Security.RateLimitAPIRead.Burst)
+		apiReadMiddlewares = append(apiReadMiddlewares, RateLimitMiddleware(apiReadLimiter, s.cfg.Security.TrustProxyHeaders, s.cfg.Security.TrustedProxyPrefixes))
+	}
+	if s.cfg.Security.RateLimitAPIWrite.Enabled {
+		apiWriteLimiter := NewRateLimiter(s.cfg.Security.RateLimitAPIWrite.RequestsPerMinute, s.cfg.Security.RateLimitAPIWrite.Burst)
+		apiWriteMiddlewares = append(apiWriteMiddlewares, RateLimitMiddleware(apiWriteLimiter, s.cfg.Security.TrustProxyHeaders, s.cfg.Security.TrustedProxyPrefixes))
+	}
+
+	mux.Handle("GET /{$}", Chain(http.HandlerFunc(s.serveSPA), uiMiddlewares...))
+	mux.Handle("GET /u", Chain(http.HandlerFunc(s.serveSPA), uiMiddlewares...))
+	mux.Handle("GET /s/{id}", Chain(http.HandlerFunc(s.scratchPage), uiMiddlewares...))
+
+	mux.Handle("GET /api/config", Chain(http.HandlerFunc(s.getUIConfig), apiReadMiddlewares...))
+	mux.Handle("GET /api/scratch/{id}", Chain(http.HandlerFunc(s.getScratch), apiReadMiddlewares...))
+	mux.Handle("GET /api/raw/{id}", Chain(http.HandlerFunc(s.rawScratch), apiReadMiddlewares...))
 
 	writeHandler := http.HandlerFunc(s.createScratch)
-	middlewares := make([]func(http.Handler) http.Handler, 0, 2)
+	writeMiddlewares := make([]func(http.Handler) http.Handler, 0, 2)
-	middlewares = append(middlewares, AllowlistMiddleware(s.cfg.Security.AllowedPrefixes, s.cfg.Security.TrustProxyHeaders, s.cfg.Security.TrustedProxyPrefixes, s.logger))
+	writeMiddlewares = append(writeMiddlewares, AllowlistMiddleware(s.cfg.Security.AllowedPrefixes, s.cfg.Security.TrustProxyHeaders, s.cfg.Security.TrustedProxyPrefixes, s.logger))
-	readMiddlewares := make([]func(http.Handler) http.Handler, 0, 1)
+	writeMiddlewares = append(writeMiddlewares, apiWriteMiddlewares...)
-	if s.cfg.Security.RateLimit.Enabled {
+	mux.Handle("POST /api/scratch", Chain(writeHandler, writeMiddlewares...))
-		writeLimiter := NewRateLimiter(s.cfg.Security.RateLimit.RequestsPerMinute, s.cfg.Security.RateLimit.Burst)
-		readLimiter := NewRateLimiter(s.cfg.Security.RateLimit.RequestsPerMinute, s.cfg.Security.RateLimit.Burst)
-		middlewares = append(middlewares, RateLimitMiddleware(writeLimiter, s.cfg.Security.TrustProxyHeaders, s.cfg.Security.TrustedProxyPrefixes))
-		readMiddlewares = append(readMiddlewares, RateLimitMiddleware(readLimiter, s.cfg.Security.TrustProxyHeaders, s.cfg.Security.TrustedProxyPrefixes))
-	}
-	mux.Handle("POST /api/scratch", Chain(writeHandler, middlewares...))
-	mux.Handle("GET /api/scratch/{id}", Chain(http.HandlerFunc(s.getScratch), readMiddlewares...))
-	mux.Handle("GET /s/{id}", Chain(http.HandlerFunc(s.scratchPage), readMiddlewares...))
-	mux.Handle("GET /api/raw/{id}", Chain(http.HandlerFunc(s.rawScratch), readMiddlewares...))
 
 	mux.Handle("GET /assets/", http.FileServerFS(webassets.StaticFS()))
 	mux.Handle("GET /static/", http.StripPrefix("/static/", http.FileServerFS(webassets.StaticFS())))
 	mux.Handle("GET /{path...}", http.HandlerFunc(s.notFoundPage))
-	return mux
+	return AccessLogMiddleware(
+		s.accessLogger,
+		s.cfg.Security.TrustProxyHeaders,
+		s.cfg.Security.TrustedProxyPrefixes,
+	)(mux)
 }
 
 func (s *Server) serveSPA(w http.ResponseWriter, r *http.Request) {
@@ -68,6 +85,7 @@ func (s *Server) getUIConfig(w http.ResponseWriter, r *http.Request) {
 	payload := map[string]any{
 		"max_upload_size_bytes": s.cfg.Limits.MaxUploadSizeBytes,
 		"upload_allowed":        s.isUploadAllowedForRequest(r),
+		"default_ttl":           s.cfg.Limits.DefaultTTL,
 	}
 	writeJSON(w, http.StatusOK, payload)
 }

internal/http/handlers_integration_test.go

@@ -162,7 +162,7 @@ func TestReadRoutesAreRateLimitedWhenEnabled(t *testing.T) {
 
 	createReq := httptest.NewRequest(http.MethodPost, "/api/scratch", bytes.NewBufferString("hello scratch"))
 	createReq.Header.Set("Content-Type", "text/plain; charset=utf-8")
-	createReq.RemoteAddr = "127.0.0.1:9111"
+	createReq.RemoteAddr = "127.0.0.2:9111"
 	createRec := httptest.NewRecorder()
 	handler.ServeHTTP(createRec, createReq)
 	if createRec.Code != http.StatusCreated {
@@ -1041,7 +1041,7 @@ func newTestHandlerAndStore(t *testing.T, opts testServerOptions) (http.Handler,
 	t.Helper()
 
 	dataDir := filepath.Join(t.TempDir(), "data")
-	store, err := storage.NewFilesystemStore(dataDir)
+	store, err := storage.NewFilesystemStore(dataDir, testStorageKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -1060,7 +1060,17 @@ func newTestHandlerAndStore(t *testing.T, opts testServerOptions) (http.Handler,
 			DataDir: dataDir,
 		},
 		Security: config.SecurityConfig{
-			RateLimit: config.RateLimitConfig{
+			RateLimitUI: config.RateLimitConfig{
+				Enabled:           opts.rateLimitEnable,
+				RequestsPerMinute: 120,
+				Burst:             1,
+			},
+			RateLimitAPIRead: config.RateLimitConfig{
+				Enabled:           opts.rateLimitEnable,
+				RequestsPerMinute: 120,
+				Burst:             1,
+			},
+			RateLimitAPIWrite: config.RateLimitConfig{
 				Enabled:           opts.rateLimitEnable,
 				RequestsPerMinute: 120,
 				Burst:             1,

internal/http/handlers_unit_test.go

@@ -15,6 +15,8 @@ import (
 	"scratchbox/internal/storage"
 )
 
+var testStorageKey = []byte("0123456789abcdef0123456789abcdef")
+
 func TestMultipartFileCount(t *testing.T) {
 	t.Parallel()
 
@@ -49,18 +51,20 @@ func TestWriteCreateErrorBranches(t *testing.T) {
 
 func TestNewServerInitializes(t *testing.T) {
 	tmp := t.TempDir()
-	store, err := storage.NewFilesystemStore(filepath.Join(tmp, "data"))
+	store, err := storage.NewFilesystemStore(filepath.Join(tmp, "data"), testStorageKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
 	cfg := config.Config{
 		Limits: config.LimitsConfig{MaxUploadSizeBytes: 1024},
 		Security: config.SecurityConfig{
-			RateLimit: config.RateLimitConfig{Enabled: false},
+			RateLimitUI:       config.RateLimitConfig{Enabled: false, RequestsPerMinute: 30, Burst: 10},
+			RateLimitAPIRead:  config.RateLimitConfig{Enabled: false, RequestsPerMinute: 30, Burst: 10},
+			RateLimitAPIWrite: config.RateLimitConfig{Enabled: false, RequestsPerMinute: 30, Burst: 10},
 		},
 	}
 
-	srv, err := NewServer(cfg, store, log.New(io.Discard, "", 0))
+	srv, err := NewServer(cfg, store, log.New(io.Discard, "", 0), log.New(io.Discard, "", 0))
 	if err != nil {
 		t.Fatalf("NewServer() error = %v", err)
 	}
@@ -118,17 +122,19 @@ func TestGetUIConfigUploadDenied(t *testing.T) {
 
 func TestWriteCreateErrorBranchesWithConfig(t *testing.T) {
 	tmp := t.TempDir()
-	store, err := storage.NewFilesystemStore(filepath.Join(tmp, "data"))
+	store, err := storage.NewFilesystemStore(filepath.Join(tmp, "data"), testStorageKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
 	cfg := config.Config{
 		Limits: config.LimitsConfig{MaxUploadSizeBytes: 1024},
 		Security: config.SecurityConfig{
-			RateLimit: config.RateLimitConfig{Enabled: false},
+			RateLimitUI:       config.RateLimitConfig{Enabled: false, RequestsPerMinute: 30, Burst: 10},
+			RateLimitAPIRead:  config.RateLimitConfig{Enabled: false, RequestsPerMinute: 30, Burst: 10},
+			RateLimitAPIWrite: config.RateLimitConfig{Enabled: false, RequestsPerMinute: 30, Burst: 10},
 		},
 	}
-	if _, err := NewServer(cfg, store, log.New(io.Discard, "", 0)); err != nil {
+	if _, err := NewServer(cfg, store, log.New(io.Discard, "", 0), log.New(io.Discard, "", 0)); err != nil {
 		t.Fatalf("NewServer() error = %v", err)
 	}
 }

internal/http/middleware.go

@@ -107,6 +107,53 @@ func RateLimitMiddleware(limiter *RateLimiter, trustProxyHeaders bool, trustedPr
 	}
 }
 
+func AccessLogMiddleware(logger *log.Logger, trustProxyHeaders bool, trustedProxies []netip.Prefix) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		if logger == nil {
+			return next
+		}
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			if !shouldLogAccessRequest(r.Method, r.URL.Path) {
+				next.ServeHTTP(w, r)
+				return
+			}
+
+			start := time.Now()
+			recorder := &accessLogResponseWriter{ResponseWriter: w}
+			next.ServeHTTP(recorder, r)
+
+			status := recorder.status
+			if status == 0 {
+				status = http.StatusOK
+			}
+			clientIP := "-"
+			if ip, ok := extractClientIP(r, trustProxyHeaders, trustedProxies); ok {
+				clientIP = ip.String()
+			}
+			logger.Printf(
+				"method=%s path=%s status=%d bytes=%d duration_ms=%d ip=%s ua=%q",
+				r.Method,
+				r.URL.RequestURI(),
+				status,
+				recorder.bytes,
+				time.Since(start).Milliseconds(),
+				clientIP,
+				r.UserAgent(),
+			)
+		})
+	}
+}
+
+func shouldLogAccessRequest(method string, path string) bool {
+	if method == http.MethodPost && path == "/api/scratch" {
+		return true
+	}
+	if method == http.MethodGet && strings.HasPrefix(path, "/api/raw/") && len(path) > len("/api/raw/") {
+		return true
+	}
+	return false
+}
+
 func Chain(handler http.Handler, middlewares ...func(http.Handler) http.Handler) http.Handler {
 	wrapped := handler
 	for i := len(middlewares) - 1; i >= 0; i-- {
@@ -115,6 +162,26 @@ func Chain(handler http.Handler, middlewares ...func(http.Handler) http.Handler)
 	return wrapped
 }
 
+type accessLogResponseWriter struct {
+	http.ResponseWriter
+	status int
+	bytes  int
+}
+
+func (w *accessLogResponseWriter) WriteHeader(statusCode int) {
+	w.status = statusCode
+	w.ResponseWriter.WriteHeader(statusCode)
+}
+
+func (w *accessLogResponseWriter) Write(p []byte) (int, error) {
+	if w.status == 0 {
+		w.status = http.StatusOK
+	}
+	n, err := w.ResponseWriter.Write(p)
+	w.bytes += n
+	return n, err
+}
+
 func extractClientIP(r *http.Request, trustProxyHeaders bool, trustedProxies []netip.Prefix) (netip.Addr, bool) {
 	remoteIP, ok := remoteIPFromRequest(r)
 	if !ok {

internal/http/middleware_test.go

@@ -1,6 +1,7 @@
 package httpapi
 
 import (
+	"bytes"
 	"encoding/json"
 	"io"
 	"log"
@@ -228,3 +229,95 @@ func TestExtractClientIPIgnoresHeadersFromUntrustedProxy(t *testing.T) {
 		t.Fatalf("extractClientIP() = (%v,%v), want (203.0.113.10,true)", ip, ok)
 	}
 }
+
+func TestAccessLogMiddlewareWritesStructuredLog(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	logger := log.New(&buf, "", 0)
+	handler := AccessLogMiddleware(logger, false, nil)(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusCreated)
+		_, _ = w.Write([]byte("ok"))
+	}))
+
+	req := httptest.NewRequest(http.MethodPost, "/api/scratch?ttl=1h", nil)
+	req.RemoteAddr = "198.51.100.12:4444"
+	req.Header.Set("User-Agent", "middleware-test")
+	rec := httptest.NewRecorder()
+	handler.ServeHTTP(rec, req)
+
+	got := buf.String()
+	if !strings.Contains(got, "method=POST") {
+		t.Fatalf("missing method field in log: %q", got)
+	}
+	if !strings.Contains(got, "path=/api/scratch?ttl=1h") {
+		t.Fatalf("missing path field in log: %q", got)
+	}
+	if !strings.Contains(got, "status=201") {
+		t.Fatalf("missing status field in log: %q", got)
+	}
+	if !strings.Contains(got, "bytes=2") {
+		t.Fatalf("missing bytes field in log: %q", got)
+	}
+	if !strings.Contains(got, "ip=198.51.100.12") {
+		t.Fatalf("missing ip field in log: %q", got)
+	}
+}
+
+func TestAccessLogMiddlewareSkipsConfigAndStaticPaths(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	logger := log.New(&buf, "", 0)
+	handler := AccessLogMiddleware(logger, false, nil)(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	reqConfig := httptest.NewRequest(http.MethodGet, "/api/config", nil)
+	reqConfig.RemoteAddr = "198.51.100.12:4444"
+	handler.ServeHTTP(httptest.NewRecorder(), reqConfig)
+
+	reqStatic := httptest.NewRequest(http.MethodGet, "/static/app.js", nil)
+	reqStatic.RemoteAddr = "198.51.100.12:4444"
+	handler.ServeHTTP(httptest.NewRecorder(), reqStatic)
+
+	reqAsset := httptest.NewRequest(http.MethodGet, "/assets/logo.svg", nil)
+	reqAsset.RemoteAddr = "198.51.100.12:4444"
+	handler.ServeHTTP(httptest.NewRecorder(), reqAsset)
+
+	reqScratchView := httptest.NewRequest(http.MethodGet, "/s/abc123", nil)
+	reqScratchView.RemoteAddr = "198.51.100.12:4444"
+	handler.ServeHTTP(httptest.NewRecorder(), reqScratchView)
+
+	reqUpload := httptest.NewRequest(http.MethodGet, "/u", nil)
+	reqUpload.RemoteAddr = "198.51.100.12:4444"
+	handler.ServeHTTP(httptest.NewRecorder(), reqUpload)
+
+	if buf.Len() != 0 {
+		t.Fatalf("expected no access logs for skipped paths, got %q", buf.String())
+	}
+}
+
+func TestAccessLogMiddlewareOnlyAllowsConfiguredRoutes(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	logger := log.New(&buf, "", 0)
+	handler := AccessLogMiddleware(logger, false, nil)(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	disallowed := httptest.NewRequest(http.MethodGet, "/api/scratch/some-id", nil)
+	disallowed.RemoteAddr = "198.51.100.12:4444"
+	handler.ServeHTTP(httptest.NewRecorder(), disallowed)
+	if buf.Len() != 0 {
+		t.Fatalf("expected no access log for disallowed route, got %q", buf.String())
+	}
+
+	allowed := httptest.NewRequest(http.MethodGet, "/api/raw/some-id", nil)
+	allowed.RemoteAddr = "198.51.100.12:4444"
+	handler.ServeHTTP(httptest.NewRecorder(), allowed)
+	if !strings.Contains(buf.String(), "method=GET path=/api/raw/some-id") {
+		t.Fatalf("expected access log for allowed route, got %q", buf.String())
+	}
+}

internal/storage/filesystem.go

@@ -3,7 +3,11 @@ package storage
 import (
 	"compress/gzip"
 	"context"
+	"crypto/aes"
+	"crypto/cipher"
 	"crypto/rand"
+	"crypto/sha256"
+	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
@@ -17,14 +21,16 @@ import (
 )
 
 const (
-	indexFilename       = "metadata.json"
+	indexFilename      = "metadata"
-	filesDirName        = "scratches"
+	filesDirName       = "scratches"
-	idBytes             = 12
+	encryptedChunkSize = 64 * 1024
-	maxCreateIDAttempts = 100
 )
 
 var ErrNotFound = errors.New("scratch not found")
 
+var encryptedFileMagic = [4]byte{'S', 'B', 'X', '1'}
+var encryptedIndexMagic = [4]byte{'S', 'M', 'D', '1'}
+
 type Metadata struct {
 	ID           string    `json:"id"`
 	FilePath     string    `json:"file_path"`
@@ -35,35 +41,63 @@ type Metadata struct {
 	Size         int64     `json:"size"`
 }
 
-type FilesystemStore struct {
+type indexDocument struct {
-	dataDir     string
+	DefaultTTL string              `json:"default_ttl,omitempty"`
-	filesDir    string
+	Scratches  map[string]Metadata `json:"scratches"`
-	index       string
-	idGenerator func() (string, error)
-
-	mu          sync.RWMutex
-	metadata    map[string]Metadata
-	reservedIDs map[string]struct{}
 }
 
-func NewFilesystemStore(dataDir string) (*FilesystemStore, error) {
+type FilesystemStore struct {
+	dataDir    string
+	filesDir   string
+	index      string
+	defaultTTL time.Duration
+	fileCipher cipher.AEAD
+
+	mu       sync.RWMutex
+	metadata map[string]Metadata
+}
+
+func NewFilesystemStore(dataDir string, encryptionKey []byte) (*FilesystemStore, error) {
+	return newFilesystemStore(dataDir, 0, encryptionKey)
+}
+
+func NewFilesystemStoreWithDefaultTTL(dataDir string, defaultTTL time.Duration, encryptionKey []byte) (*FilesystemStore, error) {
+	return newFilesystemStore(dataDir, defaultTTL, encryptionKey)
+}
+
+func newFilesystemStore(dataDir string, defaultTTL time.Duration, encryptionKey []byte) (*FilesystemStore, error) {
 	filesDir := filepath.Join(dataDir, filesDirName)
 	if err := os.MkdirAll(filesDir, 0o755); err != nil {
 		return nil, fmt.Errorf("create files dir: %w", err)
 	}
 
+	if len(encryptionKey) != 32 {
+		return nil, fmt.Errorf("storage encryption key must be 32 bytes, got %d", len(encryptionKey))
+	}
+	block, err := aes.NewCipher(encryptionKey)
+	if err != nil {
+		return nil, fmt.Errorf("init storage cipher: %w", err)
+	}
+	fileCipher, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("init storage aead: %w", err)
+	}
+
 	store := &FilesystemStore{
-		dataDir:     dataDir,
+		dataDir:    dataDir,
-		filesDir:    filesDir,
+		filesDir:   filesDir,
-		index:       filepath.Join(dataDir, indexFilename),
+		index:      filepath.Join(dataDir, indexFilename),
-		idGenerator: generateID,
+		fileCipher: fileCipher,
-		metadata:    map[string]Metadata{},
+		metadata:   map[string]Metadata{},
-		reservedIDs: map[string]struct{}{},
 	}
 	if err := store.loadIndex(); err != nil {
 		return nil, err
 	}
-	if err := store.reconcileOnStartup(time.Now()); err != nil {
+	now := time.Now().UTC()
+	if err := store.applyDefaultTTLOnStartup(defaultTTL); err != nil {
+		return nil, err
+	}
+	if err := store.reconcileOnStartup(now); err != nil {
 		return nil, err
 	}
 	return store, nil
@@ -74,107 +108,84 @@ func (s *FilesystemStore) Create(ctx context.Context, body io.Reader, contentTyp
 }
 
 func (s *FilesystemStore) CreateWithOriginalName(ctx context.Context, body io.Reader, contentType string, originalName string, ttl time.Duration) (Metadata, error) {
-	for attempt := 0; attempt < maxCreateIDAttempts; attempt++ {
+	tempFile, err := os.CreateTemp(s.filesDir, "scratch.tmp-*")
-		id, err := s.idGenerator()
+	if err != nil {
-		if err != nil {
+		return Metadata{}, fmt.Errorf("create temp file: %w", err)
-			return Metadata{}, fmt.Errorf("generate id: %w", err)
-		}
-		finalPath := filepath.Join(s.filesDir, id)
-
-		s.mu.RLock()
-		_, exists := s.metadata[id]
-		_, reserved := s.reservedIDs[id]
-		s.mu.RUnlock()
-		if exists || reserved {
-			continue
-		}
-		if _, err := os.Stat(finalPath); err == nil {
-			continue
-		} else if !errors.Is(err, os.ErrNotExist) {
-			return Metadata{}, fmt.Errorf("stat candidate scratch path: %w", err)
-		}
-
-		s.mu.Lock()
-		if _, exists := s.metadata[id]; exists {
-			s.mu.Unlock()
-			continue
-		}
-		if _, reserved := s.reservedIDs[id]; reserved {
-			s.mu.Unlock()
-			continue
-		}
-		// Reserve the ID before consuming the request body to avoid
-		// concurrent writers choosing the same ID.
-		s.reservedIDs[id] = struct{}{}
-		s.mu.Unlock()
-
-		tempFile, err := os.CreateTemp(s.filesDir, id+".tmp-*")
-		if err != nil {
-			s.mu.Lock()
-			delete(s.reservedIDs, id)
-			s.mu.Unlock()
-			return Metadata{}, fmt.Errorf("create temp file: %w", err)
-		}
-
-		gzipWriter := gzip.NewWriter(tempFile)
-		size, copyErr := io.Copy(gzipWriter, body)
-		gzipCloseErr := gzipWriter.Close()
-		closeErr := tempFile.Close()
-		if copyErr != nil {
-			_ = os.Remove(tempFile.Name())
-			s.mu.Lock()
-			delete(s.reservedIDs, id)
-			s.mu.Unlock()
-			return Metadata{}, fmt.Errorf("write scratch content: %w", copyErr)
-		}
-		if gzipCloseErr != nil {
-			_ = os.Remove(tempFile.Name())
-			s.mu.Lock()
-			delete(s.reservedIDs, id)
-			s.mu.Unlock()
-			return Metadata{}, fmt.Errorf("close gzip writer: %w", gzipCloseErr)
-		}
-		if closeErr != nil {
-			_ = os.Remove(tempFile.Name())
-			s.mu.Lock()
-			delete(s.reservedIDs, id)
-			s.mu.Unlock()
-			return Metadata{}, fmt.Errorf("close temp file: %w", closeErr)
-		}
-
-		if err := os.Rename(tempFile.Name(), finalPath); err != nil {
-			_ = os.Remove(tempFile.Name())
-			s.mu.Lock()
-			delete(s.reservedIDs, id)
-			s.mu.Unlock()
-			return Metadata{}, fmt.Errorf("atomically move scratch file: %w", err)
-		}
-
-		now := time.Now().UTC()
-		meta := Metadata{
-			ID:           id,
-			FilePath:     finalPath,
-			CreatedAt:    now,
-			ExpiresAt:    now.Add(ttl),
-			ContentType:  contentType,
-			OriginalName: normalizeOriginalName(originalName),
-			Size:         size,
-		}
-
-		s.mu.Lock()
-		delete(s.reservedIDs, id)
-		s.metadata[id] = meta
-		if err := s.persistLocked(); err != nil {
-			delete(s.metadata, id)
-			s.mu.Unlock()
-			_ = os.Remove(finalPath)
-			return Metadata{}, err
-		}
-		s.mu.Unlock()
-		return meta, nil
 	}
 
-	return Metadata{}, fmt.Errorf("failed to allocate unique scratch id after %d attempts", maxCreateIDAttempts)
+	blobHash := sha256.New()
+	blobSink := io.MultiWriter(tempFile, blobHash)
+	scratchWriter := io.Writer(blobSink)
+	encryptedWriter, err := newEncryptedFileWriter(blobSink, s.fileCipher)
+	if err != nil {
+		_ = tempFile.Close()
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, fmt.Errorf("init encrypted scratch writer: %w", err)
+	}
+	scratchWriter = encryptedWriter
+
+	gzipWriter := gzip.NewWriter(scratchWriter)
+	size, copyErr := io.Copy(gzipWriter, body)
+	gzipCloseErr := gzipWriter.Close()
+	encryptCloseErr := encryptedWriter.Close()
+	closeErr := tempFile.Close()
+	if copyErr != nil {
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, fmt.Errorf("write scratch content: %w", copyErr)
+	}
+	if gzipCloseErr != nil {
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, fmt.Errorf("close gzip writer: %w", gzipCloseErr)
+	}
+	if encryptCloseErr != nil {
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, fmt.Errorf("close encrypted writer: %w", encryptCloseErr)
+	}
+	if closeErr != nil {
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, fmt.Errorf("close temp file: %w", closeErr)
+	}
+
+	id := hex.EncodeToString(blobHash.Sum(nil))
+	finalPath := filepath.Join(s.filesDir, id)
+	if _, statErr := os.Stat(finalPath); statErr == nil {
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, errors.New("scratch id collision for content hash")
+	} else if !errors.Is(statErr, os.ErrNotExist) {
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, fmt.Errorf("stat candidate scratch path: %w", statErr)
+	}
+	if err := os.Rename(tempFile.Name(), finalPath); err != nil {
+		_ = os.Remove(tempFile.Name())
+		return Metadata{}, fmt.Errorf("atomically move scratch file: %w", err)
+	}
+
+	now := time.Now().UTC()
+	meta := Metadata{
+		ID:           id,
+		FilePath:     finalPath,
+		CreatedAt:    now,
+		ExpiresAt:    now.Add(ttl),
+		ContentType:  contentType,
+		OriginalName: normalizeOriginalName(originalName),
+		Size:         size,
+	}
+
+	s.mu.Lock()
+	if _, exists := s.metadata[id]; exists {
+		s.mu.Unlock()
+		_ = os.Remove(finalPath)
+		return Metadata{}, errors.New("scratch id collision in metadata index")
+	}
+	s.metadata[id] = meta
+	if err := s.persistLocked(); err != nil {
+		delete(s.metadata, id)
+		s.mu.Unlock()
+		_ = os.Remove(finalPath)
+		return Metadata{}, err
+	}
+	s.mu.Unlock()
+	return meta, nil
 }
 
 func normalizeOriginalName(originalName string) string {
@@ -212,7 +223,12 @@ func (s *FilesystemStore) Open(id string) (io.ReadCloser, Metadata, error) {
 		}
 		return nil, Metadata{}, fmt.Errorf("open scratch file: %w", err)
 	}
-	gzipReader, err := gzip.NewReader(file)
+	decryptedReader, decryptErr := newEncryptedFileReader(file, s.fileCipher)
+	if decryptErr != nil {
+		_ = file.Close()
+		return nil, Metadata{}, fmt.Errorf("create encrypted reader: %w", decryptErr)
+	}
+	gzipReader, err := gzip.NewReader(decryptedReader)
 	if err != nil {
 		_ = file.Close()
 		return nil, Metadata{}, fmt.Errorf("create gzip reader: %w", err)
@@ -286,22 +302,46 @@ func (s *FilesystemStore) loadIndex() error {
 		}
 		return fmt.Errorf("read metadata index: %w", err)
 	}
+	plaintext, err := decryptIndexPayload(b, s.fileCipher)
+	if err != nil {
+		return fmt.Errorf("decrypt metadata index: %w", err)
+	}
 
-	loaded := map[string]Metadata{}
+	doc := indexDocument{}
-	if err := json.Unmarshal(b, &loaded); err != nil {
+	if err := json.Unmarshal(plaintext, &doc); err != nil {
 		return fmt.Errorf("decode metadata index: %w", err)
 	}
-	s.metadata = loaded
+	if doc.Scratches == nil {
+		doc.Scratches = map[string]Metadata{}
+	}
+	s.metadata = doc.Scratches
+	if ttlRaw := strings.TrimSpace(doc.DefaultTTL); ttlRaw != "" {
+		ttl, parseErr := time.ParseDuration(ttlRaw)
+		if parseErr != nil {
+			return fmt.Errorf("decode metadata index default ttl: %w", parseErr)
+		}
+		s.defaultTTL = ttl
+	}
 	return nil
 }
 
 func (s *FilesystemStore) persistLocked() error {
 	tmp := s.index + ".tmp"
-	payload, err := json.MarshalIndent(s.metadata, "", "  ")
+	doc := indexDocument{
+		Scratches: s.metadata,
+	}
+	if s.defaultTTL > 0 {
+		doc.DefaultTTL = s.defaultTTL.String()
+	}
+	payload, err := json.MarshalIndent(doc, "", "  ")
 	if err != nil {
 		return fmt.Errorf("encode metadata index: %w", err)
 	}
-	if err := os.WriteFile(tmp, payload, 0o644); err != nil {
+	encryptedPayload, err := encryptIndexPayload(payload, s.fileCipher)
+	if err != nil {
+		return fmt.Errorf("encrypt metadata index: %w", err)
+	}
+	if err := os.WriteFile(tmp, encryptedPayload, 0o644); err != nil {
 		return fmt.Errorf("write metadata temp file: %w", err)
 	}
 	if err := os.Rename(tmp, s.index); err != nil {
@@ -310,6 +350,28 @@ func (s *FilesystemStore) persistLocked() error {
 	return nil
 }
 
+func (s *FilesystemStore) applyDefaultTTLOnStartup(defaultTTL time.Duration) error {
+	if defaultTTL <= 0 {
+		return nil
+	}
+
+	if s.defaultTTL <= 0 {
+		s.defaultTTL = defaultTTL
+		return s.persistLocked()
+	}
+	if s.defaultTTL == defaultTTL {
+		return nil
+	}
+
+	delta := defaultTTL - s.defaultTTL
+	for id, meta := range s.metadata {
+		meta.ExpiresAt = meta.ExpiresAt.Add(delta)
+		s.metadata[id] = meta
+	}
+	s.defaultTTL = defaultTTL
+	return s.persistLocked()
+}
+
 func (s *FilesystemStore) reconcileOnStartup(now time.Time) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -337,14 +399,6 @@ func (s *FilesystemStore) reconcileOnStartup(now time.Time) error {
 	return s.persistLocked()
 }
 
-func generateID() (string, error) {
-	b := make([]byte, idBytes)
-	if _, err := rand.Read(b); err != nil {
-		return "", err
-	}
-	return hex.EncodeToString(b), nil
-}
-
 type combinedReadCloser struct {
 	reader  io.Reader
 	closers []io.Closer
@@ -363,3 +417,203 @@ func (c *combinedReadCloser) Close() error {
 	}
 	return firstErr
 }
+
+type encryptedFileWriter struct {
+	dst         io.Writer
+	aead        cipher.AEAD
+	noncePrefix [4]byte
+	counter     uint64
+	pending     []byte
+}
+
+func newEncryptedFileWriter(dst io.Writer, aead cipher.AEAD) (*encryptedFileWriter, error) {
+	writer := &encryptedFileWriter{
+		dst:     dst,
+		aead:    aead,
+		pending: make([]byte, 0, encryptedChunkSize),
+	}
+	if _, err := rand.Read(writer.noncePrefix[:]); err != nil {
+		return nil, fmt.Errorf("generate nonce prefix: %w", err)
+	}
+	header := make([]byte, 0, len(encryptedFileMagic)+len(writer.noncePrefix))
+	header = append(header, encryptedFileMagic[:]...)
+	header = append(header, writer.noncePrefix[:]...)
+	if _, err := writer.dst.Write(header); err != nil {
+		return nil, fmt.Errorf("write encrypted file header: %w", err)
+	}
+	return writer, nil
+}
+
+func (w *encryptedFileWriter) Write(p []byte) (int, error) {
+	written := len(p)
+	for len(p) > 0 {
+		space := encryptedChunkSize - len(w.pending)
+		if space > len(p) {
+			space = len(p)
+		}
+		w.pending = append(w.pending, p[:space]...)
+		p = p[space:]
+		if len(w.pending) == encryptedChunkSize {
+			if err := w.flushChunk(w.pending); err != nil {
+				return written - len(p), err
+			}
+			w.pending = w.pending[:0]
+		}
+	}
+	return written, nil
+}
+
+func (w *encryptedFileWriter) Close() error {
+	if len(w.pending) == 0 {
+		return nil
+	}
+	if err := w.flushChunk(w.pending); err != nil {
+		return err
+	}
+	w.pending = w.pending[:0]
+	return nil
+}
+
+func (w *encryptedFileWriter) flushChunk(plaintext []byte) error {
+	nonce := make([]byte, w.aead.NonceSize())
+	copy(nonce, w.noncePrefix[:])
+	binary.BigEndian.PutUint64(nonce[len(w.noncePrefix):], w.counter)
+	ciphertext := w.aead.Seal(nil, nonce, plaintext, nil)
+
+	var sizeBuf [4]byte
+	binary.BigEndian.PutUint32(sizeBuf[:], uint32(len(ciphertext)))
+	if _, err := w.dst.Write(sizeBuf[:]); err != nil {
+		return fmt.Errorf("write encrypted chunk size: %w", err)
+	}
+	if _, err := w.dst.Write(ciphertext); err != nil {
+		return fmt.Errorf("write encrypted chunk payload: %w", err)
+	}
+	w.counter++
+	return nil
+}
+
+type encryptedFileReader struct {
+	src         io.Reader
+	aead        cipher.AEAD
+	noncePrefix [4]byte
+	counter     uint64
+	buf         []byte
+	offset      int
+	eof         bool
+}
+
+func newEncryptedFileReader(src io.Reader, aead cipher.AEAD) (*encryptedFileReader, error) {
+	reader := &encryptedFileReader{
+		src:  src,
+		aead: aead,
+	}
+	header := make([]byte, len(encryptedFileMagic)+len(reader.noncePrefix))
+	if _, err := io.ReadFull(src, header); err != nil {
+		return nil, fmt.Errorf("read encrypted file header: %w", err)
+	}
+	if !equalBytes(header[:len(encryptedFileMagic)], encryptedFileMagic[:]) {
+		return nil, errors.New("invalid encrypted file header")
+	}
+	copy(reader.noncePrefix[:], header[len(encryptedFileMagic):])
+	return reader, nil
+}
+
+func (r *encryptedFileReader) Read(p []byte) (int, error) {
+	for r.offset >= len(r.buf) {
+		if r.eof {
+			return 0, io.EOF
+		}
+		if err := r.loadNextChunk(); err != nil {
+			return 0, err
+		}
+	}
+	n := copy(p, r.buf[r.offset:])
+	r.offset += n
+	return n, nil
+}
+
+func (r *encryptedFileReader) loadNextChunk() error {
+	var sizeBuf [4]byte
+	_, err := io.ReadFull(r.src, sizeBuf[:])
+	if err != nil {
+		if errors.Is(err, io.EOF) {
+			r.eof = true
+			return io.EOF
+		}
+		if errors.Is(err, io.ErrUnexpectedEOF) {
+			return errors.New("truncated encrypted chunk size")
+		}
+		return fmt.Errorf("read encrypted chunk size: %w", err)
+	}
+	chunkSize := binary.BigEndian.Uint32(sizeBuf[:])
+	if chunkSize == 0 {
+		return errors.New("invalid empty encrypted chunk")
+	}
+	maxChunkSize := uint32(encryptedChunkSize + r.aead.Overhead())
+	if chunkSize > maxChunkSize {
+		return fmt.Errorf("encrypted chunk too large: %d", chunkSize)
+	}
+	ciphertext := make([]byte, chunkSize)
+	if _, err := io.ReadFull(r.src, ciphertext); err != nil {
+		return fmt.Errorf("read encrypted chunk payload: %w", err)
+	}
+	nonce := make([]byte, r.aead.NonceSize())
+	copy(nonce, r.noncePrefix[:])
+	binary.BigEndian.PutUint64(nonce[len(r.noncePrefix):], r.counter)
+	plaintext, err := r.aead.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return fmt.Errorf("decrypt chunk: %w", err)
+	}
+	r.counter++
+	r.buf = plaintext
+	r.offset = 0
+	return nil
+}
+
+func equalBytes(a, b []byte) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func encryptIndexPayload(plaintext []byte, aead cipher.AEAD) ([]byte, error) {
+	nonce := make([]byte, aead.NonceSize())
+	if _, err := rand.Read(nonce); err != nil {
+		return nil, fmt.Errorf("generate index nonce: %w", err)
+	}
+	ciphertext := aead.Seal(nil, nonce, plaintext, nil)
+	out := make([]byte, 0, len(encryptedIndexMagic)+len(nonce)+len(ciphertext))
+	out = append(out, encryptedIndexMagic[:]...)
+	out = append(out, nonce...)
+	out = append(out, ciphertext...)
+	return out, nil
+}
+
+func decryptIndexPayload(raw []byte, aead cipher.AEAD) ([]byte, error) {
+	headerLen := len(encryptedIndexMagic)
+	nonceSize := aead.NonceSize()
+	if len(raw) < headerLen+nonceSize {
+		return nil, errors.New("encrypted index is too short")
+	}
+	if !equalBytes(raw[:headerLen], encryptedIndexMagic[:]) {
+		return nil, errors.New("invalid encrypted index header")
+	}
+	nonceStart := headerLen
+	nonceEnd := nonceStart + nonceSize
+	nonce := raw[nonceStart:nonceEnd]
+	ciphertext := raw[nonceEnd:]
+	if len(ciphertext) == 0 {
+		return nil, errors.New("encrypted index ciphertext is empty")
+	}
+	plaintext, err := aead.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return nil, fmt.Errorf("decrypt index payload: %w", err)
+	}
+	return plaintext, nil
+}

internal/storage/filesystem_test.go

@@ -3,6 +3,11 @@ package storage
 import (
 	"bytes"
 	"context"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -15,10 +20,25 @@ import (
 	"time"
 )
 
+var testEncryptionKey = []byte("0123456789abcdef0123456789abcdef")
+
+func mustTestAEAD(t *testing.T) cipher.AEAD {
+	t.Helper()
+	block, err := aes.NewCipher(testEncryptionKey)
+	if err != nil {
+		t.Fatalf("aes.NewCipher() error = %v", err)
+	}
+	aead, err := cipher.NewGCM(block)
+	if err != nil {
+		t.Fatalf("cipher.NewGCM() error = %v", err)
+	}
+	return aead
+}
+
 func TestCreateStoresGzipAndOpenIsTransparent(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -36,8 +56,8 @@ func TestCreateStoresGzipAndOpenIsTransparent(t *testing.T) {
 	if err != nil {
 		t.Fatalf("ReadFile() error = %v", err)
 	}
-	if len(onDisk) < 2 || onDisk[0] != 0x1f || onDisk[1] != 0x8b {
+	if len(onDisk) < 4 || string(onDisk[:4]) != "SBX1" {
-		t.Fatalf("stored file does not have gzip header")
+		t.Fatalf("stored file does not have encrypted scratch header")
 	}
 
 	reader, _, err := store.Open(meta.ID)
@@ -54,10 +74,92 @@ func TestCreateStoresGzipAndOpenIsTransparent(t *testing.T) {
 	}
 }
 
+func TestCreateEncryptedStoreDoesNotExposeGzipHeaderOnDisk(t *testing.T) {
+	t.Parallel()
+
+	key := make([]byte, 32)
+	if _, err := rand.Read(key); err != nil {
+		t.Fatalf("rand.Read() error = %v", err)
+	}
+
+	dataDir := filepath.Join(t.TempDir(), "data")
+	store, err := NewFilesystemStore(dataDir, key)
+	if err != nil {
+		t.Fatalf("NewEncryptedFilesystemStore() error = %v", err)
+	}
+
+	original := bytes.Repeat([]byte("secret payload "), 1024)
+	meta, err := store.Create(context.Background(), bytes.NewReader(original), "text/plain", time.Hour)
+	if err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+
+	onDisk, err := os.ReadFile(meta.FilePath)
+	if err != nil {
+		t.Fatalf("ReadFile() error = %v", err)
+	}
+	if len(onDisk) < 2 {
+		t.Fatalf("encrypted file too short")
+	}
+	if onDisk[0] == 0x1f && onDisk[1] == 0x8b {
+		t.Fatalf("encrypted file unexpectedly starts with gzip header")
+	}
+
+	reader, _, err := store.Open(meta.ID)
+	if err != nil {
+		t.Fatalf("Open() error = %v", err)
+	}
+	defer reader.Close()
+	got, err := io.ReadAll(reader)
+	if err != nil {
+		t.Fatalf("ReadAll() error = %v", err)
+	}
+	if !bytes.Equal(got, original) {
+		t.Fatalf("Open() content mismatch: got %d bytes, want %d", len(got), len(original))
+	}
+
+	filePayload, err := os.ReadFile(meta.FilePath)
+	if err != nil {
+		t.Fatalf("ReadFile(encrypted) error = %v", err)
+	}
+	sum := sha256.Sum256(filePayload)
+	wantID := hex.EncodeToString(sum[:])
+	if meta.ID != wantID {
+		t.Fatalf("meta.ID = %q, want SHA-256 of encrypted blob %q", meta.ID, wantID)
+	}
+}
+
+func TestEncryptedStoreFailsToOpenWithWrongKey(t *testing.T) {
+	t.Parallel()
+
+	keyA := make([]byte, 32)
+	if _, err := rand.Read(keyA); err != nil {
+		t.Fatalf("rand.Read(keyA) error = %v", err)
+	}
+	keyB := make([]byte, 32)
+	if _, err := rand.Read(keyB); err != nil {
+		t.Fatalf("rand.Read(keyB) error = %v", err)
+	}
+
+	dataDir := filepath.Join(t.TempDir(), "data")
+	storeA, err := NewFilesystemStore(dataDir, keyA)
+	if err != nil {
+		t.Fatalf("NewEncryptedFilesystemStore(keyA) error = %v", err)
+	}
+	_, err = storeA.Create(context.Background(), bytes.NewReader([]byte("hello")), "text/plain", time.Hour)
+	if err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+
+	if _, err := NewFilesystemStore(dataDir, keyB); err == nil {
+		t.Fatalf("NewFilesystemStore() with wrong key error = nil, want non-nil")
+	}
+}
+
 func TestCreateWithOriginalNameNormalizesFilename(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -70,7 +172,7 @@ func TestCreateWithOriginalNameNormalizesFilename(t *testing.T) {
 		t.Fatalf("meta.OriginalName = %q, want %q", meta.OriginalName, "demo.txt")
 	}
 
-	reloaded, err := NewFilesystemStore(store.dataDir)
+	reloaded, err := NewFilesystemStore(store.dataDir, testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() reload error = %v", err)
 	}
@@ -83,201 +185,31 @@ func TestCreateWithOriginalNameNormalizesFilename(t *testing.T) {
 	}
 }
 
-func TestCreateWithOriginalNameRetriesOnIDCollision(t *testing.T) {
+func TestCreateWithOriginalNameSameContentGetsDifferentIDs(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
 
-	existingID := "aaaaaaaaaaaaaaaaaaaaaaaa"
+	first, err := store.CreateWithOriginalName(context.Background(), bytes.NewReader([]byte("same body")), "text/plain", "one.txt", time.Hour)
-	existingPath := filepath.Join(store.filesDir, existingID)
-	if err := os.WriteFile(existingPath, []byte{0x1f, 0x8b, 0x08, 0x00}, 0o644); err != nil {
-		t.Fatalf("WriteFile(existing collision path) error = %v", err)
-	}
-	store.mu.Lock()
-	store.metadata[existingID] = Metadata{
-		ID:          existingID,
-		FilePath:    existingPath,
-		CreatedAt:   time.Now().UTC(),
-		ExpiresAt:   time.Now().UTC().Add(time.Hour),
-		ContentType: "text/plain",
-		Size:        4,
-	}
-	store.mu.Unlock()
-
-	nextID := "bbbbbbbbbbbbbbbbbbbbbbbb"
-	calls := 0
-	store.idGenerator = func() (string, error) {
-		calls++
-		if calls == 1 {
-			return existingID, nil
-		}
-		return nextID, nil
-	}
-
-	meta, err := store.CreateWithOriginalName(context.Background(), bytes.NewReader([]byte("hello")), "text/plain", "hello.txt", time.Hour)
 	if err != nil {
-		t.Fatalf("CreateWithOriginalName() error = %v", err)
+		t.Fatalf("first CreateWithOriginalName() error = %v", err)
 	}
-	if meta.ID != nextID {
+	second, err := store.CreateWithOriginalName(context.Background(), bytes.NewReader([]byte("same body")), "text/plain", "two.txt", time.Hour)
-		t.Fatalf("meta.ID = %q, want %q", meta.ID, nextID)
-	}
-	if calls != 2 {
-		t.Fatalf("idGenerator calls = %d, want 2", calls)
-	}
-}
-
-func TestCreateWithOriginalNameFailsAfterMaxIDRetries(t *testing.T) {
-	t.Parallel()
-
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
-	if err != nil {
-		t.Fatalf("NewFilesystemStore() error = %v", err)
-	}
-
-	existingID := "cccccccccccccccccccccccc"
-	existingPath := filepath.Join(store.filesDir, existingID)
-	store.mu.Lock()
-	store.metadata[existingID] = Metadata{
-		ID:          existingID,
-		FilePath:    existingPath,
-		CreatedAt:   time.Now().UTC(),
-		ExpiresAt:   time.Now().UTC().Add(time.Hour),
-		ContentType: "text/plain",
-	}
-	store.mu.Unlock()
-
-	store.idGenerator = func() (string, error) {
-		return existingID, nil
-	}
-
-	_, err = store.CreateWithOriginalName(context.Background(), bytes.NewReader([]byte("hello")), "text/plain", "hello.txt", time.Hour)
-	if err == nil {
-		t.Fatalf("CreateWithOriginalName() error = nil, want retry exhaustion error")
-	}
-	if !strings.Contains(err.Error(), "failed to allocate unique scratch id") {
-		t.Fatalf("unexpected error: %v", err)
-	}
-}
-
-func TestCreateWithOriginalNameRetriesWhenIDIsReservedInFlight(t *testing.T) {
-	t.Parallel()
-
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
-	if err != nil {
-		t.Fatalf("NewFilesystemStore() error = %v", err)
-	}
-
-	const collideID = "abababababababababababab"
-	const uniqueID = "cdcdcdcdcdcdcdcdcdcdcdcd"
-
-	var idMu sync.Mutex
-	idCalls := 0
-	store.idGenerator = func() (string, error) {
-		idMu.Lock()
-		defer idMu.Unlock()
-		idCalls++
-		if idCalls <= 2 {
-			return collideID, nil
-		}
-		return uniqueID, nil
-	}
-
-	release := make(chan struct{})
-	firstMetaCh := make(chan Metadata, 1)
-	firstErrCh := make(chan error, 1)
-	go func() {
-		meta, createErr := store.CreateWithOriginalName(
-			context.Background(),
-			&blockingReader{release: release, payload: []byte("first upload")},
-			"text/plain",
-			"first.txt",
-			time.Hour,
-		)
-		firstMetaCh <- meta
-		firstErrCh <- createErr
-	}()
-
-	deadline := time.Now().Add(2 * time.Second)
-	for {
-		store.mu.RLock()
-		_, reserved := store.reservedIDs[collideID]
-		store.mu.RUnlock()
-		if reserved {
-			break
-		}
-		if time.Now().After(deadline) {
-			t.Fatalf("timed out waiting for first upload reservation")
-		}
-		time.Sleep(2 * time.Millisecond)
-	}
-
-	secondMeta, err := store.CreateWithOriginalName(
-		context.Background(),
-		strings.NewReader("second upload"),
-		"text/plain",
-		"second.txt",
-		time.Hour,
-	)
 	if err != nil {
 		t.Fatalf("second CreateWithOriginalName() error = %v", err)
 	}
-	if secondMeta.ID != uniqueID {
+	if first.ID == second.ID {
-		t.Fatalf("second meta.ID = %q, want %q after collision retry", secondMeta.ID, uniqueID)
+		t.Fatalf("IDs should differ because encrypted blobs include random nonce")
-	}
-	if secondMeta.ID == collideID {
-		t.Fatalf("second create reused in-flight reserved ID")
-	}
-
-	close(release)
-	firstMeta := <-firstMetaCh
-	if err := <-firstErrCh; err != nil {
-		t.Fatalf("first CreateWithOriginalName() error = %v", err)
-	}
-	if firstMeta.ID != collideID {
-		t.Fatalf("first meta.ID = %q, want %q", firstMeta.ID, collideID)
-	}
-
-	firstReader, _, err := store.Open(firstMeta.ID)
-	if err != nil {
-		t.Fatalf("Open(first) error = %v", err)
-	}
-	defer firstReader.Close()
-	firstBody, err := io.ReadAll(firstReader)
-	if err != nil {
-		t.Fatalf("ReadAll(first) error = %v", err)
-	}
-	if string(firstBody) != "first upload" {
-		t.Fatalf("first content = %q, want %q", string(firstBody), "first upload")
-	}
-
-	secondReader, _, err := store.Open(secondMeta.ID)
-	if err != nil {
-		t.Fatalf("Open(second) error = %v", err)
-	}
-	defer secondReader.Close()
-	secondBody, err := io.ReadAll(secondReader)
-	if err != nil {
-		t.Fatalf("ReadAll(second) error = %v", err)
-	}
-	if string(secondBody) != "second upload" {
-		t.Fatalf("second content = %q, want %q", string(secondBody), "second upload")
-	}
-
-	idMu.Lock()
-	totalCalls := idCalls
-	idMu.Unlock()
-	if totalCalls < 3 {
-		t.Fatalf("idGenerator call count = %d, want at least 3", totalCalls)
 	}
 }
 
 func TestGetDeleteAndNotFound(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -302,7 +234,7 @@ func TestGetDeleteAndNotFound(t *testing.T) {
 func TestDeleteExpired(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -332,7 +264,7 @@ func TestDeleteExpired(t *testing.T) {
 func TestOpenInvalidGzipFails(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -368,7 +300,7 @@ func TestNewFilesystemStoreInvalidIndex(t *testing.T) {
 	if err := os.WriteFile(filepath.Join(root, indexFilename), []byte("{bad"), 0o644); err != nil {
 		t.Fatalf("WriteFile() error = %v", err)
 	}
-	if _, err := NewFilesystemStore(root); err == nil {
+	if _, err := NewFilesystemStore(root, testEncryptionKey); err == nil {
 		t.Fatalf("NewFilesystemStore() error = nil, want invalid index error")
 	}
 }
@@ -419,15 +351,21 @@ func TestNewFilesystemStoreReconcileOnStartup(t *testing.T) {
 			Size:        1,
 		},
 	}
-	payload, err := json.Marshal(meta)
+	payload, err := json.Marshal(indexDocument{
+		Scratches: meta,
+	})
 	if err != nil {
 		t.Fatalf("json.Marshal() error = %v", err)
 	}
-	if err := os.WriteFile(filepath.Join(root, indexFilename), payload, 0o644); err != nil {
+	encryptedPayload, err := encryptIndexPayload(payload, mustTestAEAD(t))
+	if err != nil {
+		t.Fatalf("encryptIndexPayload() error = %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(root, indexFilename), encryptedPayload, 0o644); err != nil {
 		t.Fatalf("WriteFile index error = %v", err)
 	}
 
-	store, err := NewFilesystemStore(root)
+	store, err := NewFilesystemStore(root, testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -442,6 +380,63 @@ func TestNewFilesystemStoreReconcileOnStartup(t *testing.T) {
 	}
 }
 
+func TestNewFilesystemStoreWithDefaultTTLShiftsExpiriesOnTTLChange(t *testing.T) {
+	t.Parallel()
+
+	dataDir := filepath.Join(t.TempDir(), "data")
+	store, err := NewFilesystemStoreWithDefaultTTL(dataDir, time.Hour, testEncryptionKey)
+	if err != nil {
+		t.Fatalf("NewFilesystemStoreWithDefaultTTL() error = %v", err)
+	}
+
+	meta, err := store.Create(context.Background(), bytes.NewReader([]byte("hello")), "text/plain", time.Hour)
+	if err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+	originalExpiry := meta.ExpiresAt
+
+	reloaded, err := NewFilesystemStoreWithDefaultTTL(dataDir, 2*time.Hour, testEncryptionKey)
+	if err != nil {
+		t.Fatalf("NewFilesystemStoreWithDefaultTTL() reload error = %v", err)
+	}
+	got, err := reloaded.Get(meta.ID)
+	if err != nil {
+		t.Fatalf("Get() error = %v", err)
+	}
+
+	wantExpiry := originalExpiry.Add(time.Hour)
+	if !got.ExpiresAt.Equal(wantExpiry) {
+		t.Fatalf("ExpiresAt = %s, want %s", got.ExpiresAt, wantExpiry)
+	}
+
+	again, err := NewFilesystemStoreWithDefaultTTL(dataDir, 2*time.Hour, testEncryptionKey)
+	if err != nil {
+		t.Fatalf("NewFilesystemStoreWithDefaultTTL() second reload error = %v", err)
+	}
+	gotAgain, err := again.Get(meta.ID)
+	if err != nil {
+		t.Fatalf("Get() second reload error = %v", err)
+	}
+	if !gotAgain.ExpiresAt.Equal(wantExpiry) {
+		t.Fatalf("ExpiresAt after unchanged TTL = %s, want %s", gotAgain.ExpiresAt, wantExpiry)
+	}
+
+	indexRaw, err := os.ReadFile(filepath.Join(dataDir, indexFilename))
+	if err != nil {
+		t.Fatalf("ReadFile(index) error = %v", err)
+	}
+	if bytes.Contains(indexRaw, []byte(`"default_ttl"`)) {
+		t.Fatalf("index should not be plaintext JSON")
+	}
+	indexPlaintext, err := decryptIndexPayload(indexRaw, mustTestAEAD(t))
+	if err != nil {
+		t.Fatalf("decryptIndexPayload() error = %v", err)
+	}
+	if !bytes.Contains(indexPlaintext, []byte(`"default_ttl": "2h0m0s"`)) {
+		t.Fatalf("decrypted index missing default ttl marker: %s", string(indexPlaintext))
+	}
+}
+
 type errCloser struct{}
 
 func (errCloser) Close() error { return errors.New("close failed") }
@@ -465,7 +460,7 @@ func (failingReader) Read(_ []byte) (int, error) { return 0, errors.New("boom")
 func TestCreateRollbackOnPersistFailure(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -487,7 +482,7 @@ func TestCreateRollbackOnPersistFailure(t *testing.T) {
 func TestCreateReaderFailure(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -499,7 +494,7 @@ func TestCreateReaderFailure(t *testing.T) {
 func TestDeletePersistFailureRestoresEntry(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -525,7 +520,7 @@ func TestDeletePersistFailureRestoresEntry(t *testing.T) {
 func TestDeleteRemoveFailure(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -557,7 +552,7 @@ func TestDeleteRemoveFailure(t *testing.T) {
 func TestDeleteExpiredPersistFailureRestoresEntries(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -583,7 +578,7 @@ func TestDeleteExpiredPersistFailureRestoresEntries(t *testing.T) {
 func TestDeleteExpiredRemoveFailure(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
@@ -619,106 +614,45 @@ func TestNewFilesystemStoreFailsWhenDataDirIsFile(t *testing.T) {
 	if err := os.WriteFile(filePath, []byte("x"), 0o644); err != nil {
 		t.Fatalf("WriteFile() error = %v", err)
 	}
-	if _, err := NewFilesystemStore(filePath); err == nil {
+	if _, err := NewFilesystemStore(filePath, testEncryptionKey); err == nil {
 		t.Fatalf("NewFilesystemStore() error = nil, want mkdir failure")
 	}
 }
 
-type blockingReader struct {
+func TestNewFilesystemStoreRequires32ByteKey(t *testing.T) {
-	release <-chan struct{}
-	payload []byte
-	sent    bool
-}
-
-func (r *blockingReader) Read(p []byte) (int, error) {
-	if r.sent {
-		return 0, io.EOF
-	}
-	<-r.release
-	r.sent = true
-	return copy(p, r.payload), nil
-}
-
-func TestCreateReservationIsNotVisibleToCleanupOrReads(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	dataDir := filepath.Join(t.TempDir(), "data")
+	if _, err := NewFilesystemStore(dataDir, nil); err == nil {
+		t.Fatalf("NewFilesystemStore() with nil key error = nil, want non-nil")
+	}
+	if _, err := NewFilesystemStore(dataDir, []byte("short")); err == nil {
+		t.Fatalf("NewFilesystemStore() with short key error = nil, want non-nil")
+	}
+}
+
+func TestNewFilesystemStoreFailsToLoadEncryptedIndexWithWrongKey(t *testing.T) {
+	t.Parallel()
+
+	dataDir := filepath.Join(t.TempDir(), "data")
+	store, err := NewFilesystemStore(dataDir, testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}
-
+	if _, err := store.Create(context.Background(), bytes.NewReader([]byte("hello")), "text/plain", time.Hour); err != nil {
-	const reservedID = "ffffffffffffffffffffffff"
+		t.Fatalf("Create() error = %v", err)
-	store.idGenerator = func() (string, error) {
-		return reservedID, nil
 	}
 
-	release := make(chan struct{})
+	wrongKey := []byte("abcdef0123456789abcdef0123456789")
-	createErrCh := make(chan error, 1)
+	if _, err := NewFilesystemStore(dataDir, wrongKey); err == nil {
-	go func() {
+		t.Fatalf("NewFilesystemStore() with wrong key error = nil, want non-nil")
-		_, createErr := store.CreateWithOriginalName(
-			context.Background(),
-			&blockingReader{release: release, payload: []byte("in-flight")},
-			"text/plain",
-			"",
-			time.Hour,
-		)
-		createErrCh <- createErr
-	}()
-
-	deadline := time.Now().Add(2 * time.Second)
-	for {
-		store.mu.RLock()
-		_, reserved := store.reservedIDs[reservedID]
-		_, visible := store.metadata[reservedID]
-		store.mu.RUnlock()
-		if reserved {
-			if visible {
-				t.Fatalf("in-flight ID should not appear in metadata")
-			}
-			break
-		}
-		if time.Now().After(deadline) {
-			t.Fatalf("timed out waiting for ID reservation")
-		}
-		time.Sleep(2 * time.Millisecond)
-	}
-
-	if _, err := store.Get(reservedID); !errors.Is(err, ErrNotFound) {
-		t.Fatalf("Get() during in-flight create error = %v, want ErrNotFound", err)
-	}
-
-	deleted, err := store.DeleteExpired(time.Now().UTC())
-	if err != nil {
-		t.Fatalf("DeleteExpired() error = %v", err)
-	}
-	if deleted != 0 {
-		t.Fatalf("DeleteExpired() = %d, want 0 for in-flight create", deleted)
-	}
-
-	close(release)
-	if err := <-createErrCh; err != nil {
-		t.Fatalf("CreateWithOriginalName() error = %v", err)
-	}
-
-	reader, _, err := store.Open(reservedID)
-	if err != nil {
-		t.Fatalf("Open() error = %v", err)
-	}
-	defer reader.Close()
-
-	body, err := io.ReadAll(reader)
-	if err != nil {
-		t.Fatalf("ReadAll() error = %v", err)
-	}
-	if string(body) != "in-flight" {
-		t.Fatalf("Open() content = %q, want %q", string(body), "in-flight")
 	}
 }
 
 func TestConcurrentCreateWithOriginalNameProducesUniqueReadableEntries(t *testing.T) {
 	t.Parallel()
 
-	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"))
+	store, err := NewFilesystemStore(filepath.Join(t.TempDir(), "data"), testEncryptionKey)
 	if err != nil {
 		t.Fatalf("NewFilesystemStore() error = %v", err)
 	}

web/ui/src/App.svelte

@@ -1,13 +1,12 @@
 <script>
   import { onDestroy, onMount } from "svelte";
 
-  let mode = $state("text");
-  let content = $state("");
   let selectedFile = $state(null);
   let loading = $state(false);
   let errorMessage = $state("");
 
   let maxUploadSizeBytes = $state(0);
+  let defaultTTL = $state("15m");
   let uploadAllowed = $state(true);
   let configError = $state("");
 
@@ -20,12 +19,16 @@
   let viewContent = $state("");
   let viewIsBinary = $state(false);
   let viewIsImage = $state(false);
+  let viewIsVideo = $state(false);
+  let copyStatusMessage = $state("");
+  let copyStatusKind = $state("");
   let refreshTriggered = $state(false);
   let nowMs = $state(Date.now());
 
   let nowTicker = null;
 
   const maxUploadSizeDisplay = $derived(formatBytes(maxUploadSizeBytes, true));
+  const defaultTTLDisplay = $derived(formatTTLDisplay(defaultTTL));
 
   onMount(async () => {
     nowTicker = window.setInterval(() => {
@@ -89,16 +92,18 @@
       const max = Number.parseInt(String(data.max_upload_size_bytes ?? "0"), 10);
       maxUploadSizeBytes = Number.isFinite(max) ? max : 0;
       uploadAllowed = Boolean(data.upload_allowed);
+      defaultTTL = String(data.default_ttl ?? "").trim() || "15m";
     } catch (err) {
       configError = err instanceof Error ? err.message : String(err);
       maxUploadSizeBytes = 0;
       uploadAllowed = true;
+      defaultTTL = "15m";
     }
   }
 
   async function loadScratchView() {
     if (!scratchID) {
-      viewError = "Scratch id is missing.";
+      viewError = "Scratch ID is missing.";
       return;
     }
 
@@ -108,6 +113,9 @@
     viewContent = "";
     viewIsBinary = false;
     viewIsImage = false;
+    viewIsVideo = false;
+    copyStatusMessage = "";
+    copyStatusKind = "";
     refreshTriggered = false;
 
     try {
@@ -119,14 +127,14 @@
           return;
         }
         const msg = await metaResponse.text();
-        throw new Error(msg || `failed to load scratch metadata (${metaResponse.status})`);
+        throw new Error(msg || `Failed to load scratch metadata (${metaResponse.status}).`);
       }
       viewMeta = await metaResponse.json();
 
       const rawResponse = await fetch(`/api/raw/${encodeURIComponent(scratchID)}`);
       if (!rawResponse.ok) {
         const msg = await rawResponse.text();
-        throw new Error(msg || `failed to load scratch content (${rawResponse.status})`);
+        throw new Error(msg || `Failed to load scratch content (${rawResponse.status}).`);
       }
 
       const contentType = rawResponse.headers.get("content-type") ?? "";
@@ -134,10 +142,17 @@
         viewContent = await rawResponse.text();
         viewIsBinary = false;
         viewIsImage = false;
+        viewIsVideo = false;
       } else if (isBrowserImageContentType(contentType)) {
         viewIsImage = true;
         viewIsBinary = false;
+        viewIsVideo = false;
+      } else if (isBrowserVideoContentType(contentType)) {
+        viewIsVideo = true;
+        viewIsImage = false;
+        viewIsBinary = false;
       } else {
+        viewIsVideo = false;
         viewIsImage = false;
         viewIsBinary = true;
       }
@@ -187,8 +202,81 @@
     );
   }
 
+  const browserImageContentTypes = new Set([
+    "image/apng",
+    "image/avif",
+    "image/gif",
+    "image/jpeg",
+    "image/png",
+    "image/svg+xml",
+    "image/webp",
+    "image/bmp",
+    "image/x-icon",
+    "image/vnd.microsoft.icon"
+  ]);
+
+  const browserVideoContentTypes = new Set([
+    "video/mp4",
+    "video/webm",
+    "video/ogg"
+  ]);
+
+  function normalizeContentType(contentType) {
+    return String(contentType).toLowerCase().split(";")[0].trim();
+  }
+
   function isBrowserImageContentType(contentType) {
-    return String(contentType).toLowerCase().startsWith("image/");
+    return browserImageContentTypes.has(normalizeContentType(contentType));
+  }
+
+  function isBrowserVideoContentType(contentType) {
+    return browserVideoContentTypes.has(normalizeContentType(contentType));
+  }
+
+  function formatTTLDisplay(rawTTL) {
+    const source = String(rawTTL ?? "").trim().toLowerCase();
+    if (!source) {
+      return "15 minutes";
+    }
+
+    const matches = Array.from(source.matchAll(/(\d+)\s*([hms])/g));
+    if (matches.length === 0) {
+      return rawTTL;
+    }
+
+    let hours = 0;
+    let minutes = 0;
+    let seconds = 0;
+    for (const match of matches) {
+      const value = Number.parseInt(match[1], 10);
+      if (!Number.isFinite(value) || value <= 0) {
+        continue;
+      }
+      const unit = match[2];
+      if (unit === "h") {
+        hours += value;
+      } else if (unit === "m") {
+        minutes += value;
+      } else if (unit === "s") {
+        seconds += value;
+      }
+    }
+
+    const parts = [];
+    if (hours > 0) {
+      parts.push(`${hours} ${hours === 1 ? "hour" : "hours"}`);
+    }
+    if (minutes > 0) {
+      parts.push(`${minutes} ${minutes === 1 ? "minute" : "minutes"}`);
+    }
+    if (seconds > 0) {
+      parts.push(`${seconds} ${seconds === 1 ? "second" : "seconds"}`);
+    }
+
+    if (parts.length === 0) {
+      return rawTTL;
+    }
+    return parts.join(" ");
   }
 
   $effect(() => {
@@ -231,21 +319,43 @@
     return `${seconds}s`;
   }
 
-  function switchMode(nextMode) {
+  function onFileChange(event) {
-    if (loading || nextMode === mode) {
+    selectedFile = event.currentTarget.files?.[0] ?? null;
+  }
+
+  async function copyScratchURL() {
+    if (!viewMeta?.raw_url) {
       return;
     }
-    mode = nextMode;
+
-    errorMessage = "";
+    copyStatusMessage = "";
-    if (mode === "text") {
+    copyStatusKind = "";
-      selectedFile = null;
+
-    } else {
+    const absoluteRawURL = new URL(String(viewMeta.raw_url), window.location.origin).toString();
-      content = "";
+    try {
+      await navigator.clipboard.writeText(absoluteRawURL);
+      copyStatusMessage = "Copied download URL.";
+      copyStatusKind = "success";
+    } catch {
+      copyStatusMessage = "Unable to copy URL. Copy it manually from the address bar.";
+      copyStatusKind = "error";
     }
   }
 
-  function onFileChange(event) {
+  function openScratchRawURL() {
-    selectedFile = event.currentTarget.files?.[0] ?? null;
+    if (!viewMeta?.raw_url) {
+      return;
+    }
+    const absoluteRawURL = new URL(String(viewMeta.raw_url), window.location.origin).toString();
+    window.open(absoluteRawURL, "_blank", "noopener,noreferrer");
+  }
+
+  function navigateTo(path) {
+    const destination = String(path ?? "").trim();
+    if (!destination) {
+      return;
+    }
+    window.location.assign(destination);
   }
 
   async function onSubmit(event) {
@@ -260,40 +370,23 @@
 
     errorMessage = "";
 
-    const trimmedContent = content.trim();
+    if (!selectedFile) {
-    if (mode === "text") {
+      errorMessage = "Choose a file before creating a scratch.";
-      if (!trimmedContent) {
+      return;
-        errorMessage = "Enter text content before creating a scratch.";
+    }
-        return;
+    if (maxUploadSizeBytes > 0 && selectedFile.size > maxUploadSizeBytes) {
-      }
+      errorMessage = `Selected file is too large (${formatBytes(selectedFile.size, true)}). Max upload size is ${maxUploadSizeDisplay}.`;
-    } else {
+      return;
-      if (!selectedFile) {
-        errorMessage = "Choose a file before creating a scratch.";
-        return;
-      }
-      if (maxUploadSizeBytes > 0 && selectedFile.size > maxUploadSizeBytes) {
-        errorMessage = `Selected file is too large (${formatBytes(selectedFile.size, true)}). Max upload size is ${maxUploadSizeDisplay}.`;
-        return;
-      }
     }
 
     loading = true;
     try {
-      let response;
+      const formData = new FormData();
-      if (mode === "file") {
+      formData.append("file", selectedFile);
-        const formData = new FormData();
+      const response = await fetch("/api/scratch", {
-        formData.append("file", selectedFile);
+        method: "POST",
-        response = await fetch("/api/scratch", {
+        body: formData
-          method: "POST",
+      });
-          body: formData
-        });
-      } else {
-        response = await fetch("/api/scratch", {
-          method: "POST",
-          headers: { "Content-Type": "text/plain; charset=utf-8" },
-          body: trimmedContent
-        });
-      }
 
       if (!response.ok) {
         const message = await response.text();
@@ -308,7 +401,7 @@
       window.location.assign(viewURL);
       return;
     } catch (err) {
-      if (mode === "file" && err instanceof TypeError) {
+      if (err instanceof TypeError) {
         errorMessage = `Upload failed before the server returned a response. Max upload size is ${maxUploadSizeDisplay}.`;
       } else {
         errorMessage = err instanceof Error ? err.message : String(err);
@@ -323,22 +416,20 @@
   <header class="site-header">
     <div class="brand-row">
       <a class="brand" href="/">Scratchbox</a>
-      <span class="tagline">Quick unauthenticated scratch uploads</span>
     </div>
     <nav class="site-nav" aria-label="Primary">
-      <a class="link-button nav-button" href="/">Home</a>
+      <button class="link-button nav-button action-button" type="button" onclick={() => navigateTo("/")}>Home</button>
       {#if uploadAllowed}
-        <a class="link-button nav-button" href="/u">Upload</a>
+        <button class="link-button nav-button action-button" type="button" onclick={() => navigateTo("/u")}>Upload</button>
       {/if}
     </nav>
   </header>
 
   {#if routeMode === "home"}
     <section class="panel">
-      <h1>Share scratch files and text quickly</h1>
+      <h1>Share scratch files quickly</h1>
       <p>
-        Scratchbox is a minimal temporary upload service. Every upload creates one scratch with an expiration
+        Scratchbox is a minimal temporary upload service with expiration.
-        timestamp. It supports plain text and single file uploads, plus direct raw retrieval for automation.
       </p>
       <p>
         No accounts, no sessions, no friction. Create a scratch, grab the URL, and share it.
@@ -350,7 +441,7 @@
   {:else if routeMode === "view"}
     <section class="panel">
       {#if viewLoading}
-        <p>Loading scratch...</p>
+        <p>Loading scratch content...</p>
       {:else if viewError}
         <section id="error" class="error">{viewError}</section>
       {:else if viewMeta}
@@ -361,21 +452,29 @@
             alt={`Scratch ${scratchID}`}
             loading="lazy"
           />
-        {:else if viewIsBinary}
+        {:else if viewIsVideo}
-          <p>This scratch looks binary and is not rendered in-page. Use the raw link.</p>
+          <video class="scratch-video" controls preload="metadata">
-        {:else}
+            <source src={viewMeta.raw_url} type={viewMeta.content_type} />
+            Your browser does not support inline video playback.
+          </video>
+        {:else if !viewIsBinary}
           <pre>{viewContent}</pre>
         {/if}
 
         <p><strong>Expires in:</strong> {expiresInText(viewMeta.expires_at, nowMs)}</p>
-        <p><a class="link-button" href={viewMeta.raw_url} target="_blank" rel="noreferrer">Download</a></p>
+        <p class="scratch-actions">
+          <button class="link-button action-button" type="button" onclick={openScratchRawURL}>Download</button>
+          <button class="link-button action-button" type="button" onclick={copyScratchURL}>Copy Link</button>
+        </p>
+        {#if copyStatusMessage}
+          <p class={copyStatusKind === "error" ? "copy-status error" : "copy-status"}>{copyStatusMessage}</p>
+        {/if}
       {/if}
     </section>
   {:else if routeMode === "upload"}
     <section class="panel">
-      <h1>Upload</h1>
+      <p class="helper">Size limit: {maxUploadSizeDisplay}</p>
-      <p>Create an unauthenticated scratch. It expires automatically.</p>
+      <p class="helper">Expiration: {defaultTTLDisplay}</p>
-      <p class="helper">Max upload size: {maxUploadSizeDisplay}</p>
       {#if configError}
         <p class="helper warning">Could not load UI config: {configError}</p>
       {/if}
@@ -385,59 +484,18 @@
         </section>
       {:else}
         <form id="scratch-form" onsubmit={onSubmit}>
-          <fieldset class="mode-picker">
+          <section id="file-panel" class="input-panel">
-            <legend>Upload mode</legend>
+            <label for="file">Select a file to upload</label>
-            <div class="mode-buttons" role="tablist" aria-label="Upload mode">
+            <input
-              <button
+              id="file"
-                id="mode-text"
+              name="file"
-                type="button"
+              type="file"
-                class:mode-button={true}
+              onchange={onFileChange}
-                class:is-active={mode === "text"}
+              disabled={loading}
-                aria-pressed={mode === "text"}
+            />
-                onclick={() => switchMode("text")}
+          </section>
-              >
-                Text
-              </button>
-              <button
-                id="mode-file"
-                type="button"
-                class:mode-button={true}
-                class:is-active={mode === "file"}
-                aria-pressed={mode === "file"}
-                onclick={() => switchMode("file")}
-              >
-                File
-              </button>
-            </div>
-          </fieldset>
 
-          {#if mode === "text"}
+          <button class="link-button nav-button action-button submit-button" type="submit" disabled={loading}>
-            <section id="text-panel" class="input-panel">
-              <label for="content">Text content</label>
-              <textarea
-                id="content"
-                name="content"
-                rows="14"
-                placeholder="Paste text here"
-                bind:value={content}
-                disabled={loading}
-              ></textarea>
-            </section>
-          {:else}
-            <section id="file-panel" class="input-panel">
-              <label for="file">File upload</label>
-              <input
-                id="file"
-                name="file"
-                type="file"
-                onchange={onFileChange}
-                disabled={loading}
-              />
-              <p class="helper">Upload one file per scratch.</p>
-            </section>
-          {/if}
-
-          <button type="submit" disabled={loading}>
             {#if loading}Creating...{:else}Create scratch{/if}
           </button>
         </form>
@@ -459,9 +517,6 @@
     </section>
   {/if}
 
-  <footer class="site-footer">
-    <p>Scratchbox - simple temporary uploads</p>
-  </footer>
 </main>
 
 <style>
@@ -479,15 +534,13 @@
   }
 
   .site-header,
-  .site-footer,
   .panel {
     border: 1px solid #2a3243;
     border-radius: 10px;
     background: #101726;
   }
 
-  .site-header,
+  .site-header {
-  .site-footer {
     padding: 1rem 1.1rem;
   }
 
@@ -511,11 +564,6 @@
     color: #f5f7fc;
   }
 
-  .tagline {
-    color: #b1b7c7;
-    font-size: 0.95rem;
-  }
-
   .site-nav {
     display: flex;
     gap: 0.85rem;
@@ -526,11 +574,6 @@
     padding: 1.2rem;
   }
 
-  .site-footer {
-    margin-top: 1rem;
-    color: #b1b7c7;
-  }
-
   .helper {
     color: #b1b7c7;
     margin-top: 0.5rem;
@@ -559,38 +602,26 @@
     color: #f4c16e;
   }
 
-  .mode-picker,
+  .scratch-actions {
+    display: flex;
+    align-items: center;
+    gap: 0.6rem;
+  }
+
+  .action-button {
+    cursor: pointer;
+  }
+
+  .copy-status {
+    margin-top: 0.35rem;
+    color: #9be8ac;
+  }
+
   .input-panel,
   #error {
     margin-top: 1rem;
   }
 
-  .mode-picker {
-    border: 1px solid #2a3243;
-    border-radius: 8px;
-    padding: 0.75rem;
-  }
-
-  .mode-buttons {
-    display: flex;
-    gap: 0.5rem;
-  }
-
-  .mode-button {
-    border: 1px solid #2a3243;
-    border-radius: 8px;
-    background: #121826;
-    color: #e7ebf3;
-    padding: 0.4rem 0.8rem;
-    cursor: pointer;
-  }
-
-  .mode-button.is-active {
-    background: #2b4b89;
-    border-color: #4a75c4;
-  }
-
-  textarea,
   input[type="file"] {
     margin-top: 0.5rem;
     width: 100%;
@@ -601,14 +632,8 @@
     padding: 0.7rem;
   }
 
-  button[type="submit"] {
+  .submit-button {
     margin-top: 1rem;
-    border: 1px solid #2f67c8;
-    background: #2b4b89;
-    color: #f2f5fb;
-    border-radius: 8px;
-    padding: 0.6rem 1rem;
-    cursor: pointer;
   }
 
   button[disabled] {
@@ -635,6 +660,15 @@
     background: #0b0e14;
   }
 
+  .scratch-video {
+    display: block;
+    width: 100%;
+    max-height: 70vh;
+    border: 1px solid #2a3243;
+    border-radius: 8px;
+    background: #0b0e14;
+  }
+
   .error {
     color: #ff9b9b;
   }