Parse the age identity key once and accept every identity in it (closes #165)

Restore and verify --deep now parse the configured age secret key a single time through a new helper that uses age.ParseIdentities and hands every identity to age.Decrypt. A key file with several identities (a whole age-keygen file) is fully accepted, so a blob encrypted to any of its recipients decrypts, not just the first.

The helper is the first step of both commands, so a missing or unparseable key fails before anything is downloaded. Its error names the config source and never echoes the key value. config.extractAgeSecretKey and its silent fallback are removed; the key is stored raw and parsed only where decryption happens. README, the restore help, and the missing-key error now read the key from a file with \$(cat ...) rather than typed literally, keeping it out of shell history.

Model: opus-4-8

README.md

@@ -74,11 +74,16 @@ Requirements that no existing tool meets:
 # verify a snapshot (shallow: checks all blobs are present with the listed size)
 vaultik snapshot verify <snapshot-id>
 
+# put the private key file in the environment (reading it from the file
+# keeps the key out of your shell history); the whole age-keygen file,
+# with one or more identities, is accepted
+export VAULTIK_AGE_SECRET_KEY="$(cat vaultik_backup_private_key.txt)"
+
 # deep verify (downloads and cryptographically verifies every blob)
-VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...' vaultik snapshot verify --deep <snapshot-id>
+vaultik snapshot verify --deep <snapshot-id>
 
 # restore (requires the private key)
-VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...' vaultik snapshot restore <snapshot-id> /tmp/restored
+vaultik snapshot restore <snapshot-id> /tmp/restored
 
 # daily cron job: back up, keep a 4-week rolling window of snapshots
 # 0 3 * * * vaultik snapshot create --cron --prune --keep-newer-than 4w
@@ -119,15 +124,17 @@ Use that remote key — the hex printed inside `<remote only:...>`, or the
 full `remote_key` from `snapshot list --json` — to restore and verify:
 
 ```sh
+# put the private key file in the environment (reading it from the file
+# keeps the key out of your shell history)
+export VAULTIK_AGE_SECRET_KEY="$(cat vaultik_backup_private_key.txt)"
+
 # restore everything to /tmp/restored, then check every restored file's
 # chunk hashes
-VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...' \
-  vaultik snapshot restore --verify <remote-key> /tmp/restored
+vaultik snapshot restore --verify <remote-key> /tmp/restored
 
 # optionally, deep-verify the snapshot against the store (downloads and
 # cryptographically checks every blob)
-VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...' \
-  vaultik snapshot verify --deep <remote-key>
+vaultik snapshot verify --deep <remote-key>
 ```
 
 `age_recipients` (the public key) is not needed to restore — only the
@@ -217,7 +224,7 @@ and `vaultik prune --json | jq .` both work as written.
 
 ### environment variables
 
-* `VAULTIK_AGE_SECRET_KEY`: Age private key for decryption (required for `snapshot restore` and `snapshot verify --deep`)
+* `VAULTIK_AGE_SECRET_KEY`: Age private key for decryption (required for `snapshot restore` and `snapshot verify --deep`). May hold the whole `age-keygen` file — comments and every identity in it are accepted. Set it from the file, e.g. `export VAULTIK_AGE_SECRET_KEY="$(cat vaultik_backup_private_key.txt)"`, so the key is not typed into your shell history.
 * `VAULTIK_CONFIG`: Path to config file (overridden by `--config`)
 * `VAULTIK_INDEX_PATH`: Override local SQLite index path
 * `VAULTIK_CPUPROFILE`: Write a CPU profile to this path for the duration of the run (development/debugging)

internal/blobgen/reader.go

@@ -20,10 +20,12 @@ type Reader struct {
 	bytesRead    int64
 }
 
-// NewReader creates a new Reader that decrypts, decompresses, and verifies data
-func NewReader(r io.Reader, identity age.Identity) (*Reader, error) {
+// NewReader creates a new Reader that decrypts, decompresses, and verifies
+// data. Every supplied identity is offered to age.Decrypt, so a blob
+// encrypted to any one of them can be read.
+func NewReader(r io.Reader, identities ...age.Identity) (*Reader, error) {
 	// Create decryption reader
-	decReader, err := age.Decrypt(r, identity)
+	decReader, err := age.Decrypt(r, identities...)
 	if err != nil {
 		return nil, fmt.Errorf("creating decryption reader: %w", err)
 	}

internal/cli/snapshot_restore.go

@@ -35,8 +35,12 @@ The snapshot may be named by its ID or, when restoring on a host with no
 local index, by the remote key that 'snapshot list' prints for a
 remote-only snapshot (an unambiguous leading part is enough).
 
-Requires the VAULTIK_AGE_SECRET_KEY environment variable to be set with
-the age private key.
+Requires the age private key in the VAULTIK_AGE_SECRET_KEY environment
+variable. The variable may hold the whole age-keygen file (comments and
+all of its identities are accepted); read it from the file rather than
+typing the key, so it does not land in your shell history:
+
+  export VAULTIK_AGE_SECRET_KEY="$(cat vaultik_backup_private_key.txt)"
 
 Examples:
   # Restore entire snapshot

internal/cli/snapshot_restore_test.go

@@ -0,0 +1,37 @@
+package cli //nolint:testpackage // exercises the unexported command constructor
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/spf13/pflag"
+)
+
+// TestRestoreCommandDoesNotTakeKeyAsArgument guards the fix for the age
+// key being echoed on the command line: restore must take the key only
+// from the environment, never as a flag value, and its help must show the
+// file-based form rather than a literal key that would land in shell
+// history.
+func TestRestoreCommandDoesNotTakeKeyAsArgument(t *testing.T) {
+	t.Parallel()
+
+	cmd := newSnapshotRestoreCommand()
+
+	cmd.Flags().VisitAll(func(f *pflag.Flag) {
+		lower := strings.ToLower(f.Name)
+		for _, banned := range []string{"key", "secret", "age", "identity"} {
+			if strings.Contains(lower, banned) {
+				t.Errorf("restore must not accept the key as a flag; found --%s", f.Name)
+			}
+		}
+	})
+
+	help := cmd.Long
+	if strings.Contains(help, "AGE-SECRET-KEY-") {
+		t.Error("restore help must not show a literal age private key to type")
+	}
+
+	if !strings.Contains(help, "$(cat ") {
+		t.Error("restore help should read the key from a file, e.g. $(cat ...)")
+	}
+}

internal/config/config.go

@@ -135,6 +135,26 @@ func (c *Config) SnapshotNames() []string {
 	return names
 }
 
+// Names of the two places the age secret key can be configured, used by
+// AgeSecretKeySourceName for error messages that must not echo the value.
+//
+//nolint:gosec // G101: these are the names of the config sources, not a key
+const (
+	ageSecretKeySourceEnv    = "VAULTIK_AGE_SECRET_KEY"
+	ageSecretKeySourceConfig = "age_secret_key"
+)
+
+// AgeSecretKeySourceName returns the human name of where AgeSecretKey was
+// configured. A Config built directly (as in tests) has no recorded
+// source, so it reports the config-file field name.
+func (c *Config) AgeSecretKeySourceName() string {
+	if c.AgeSecretKeySource != "" {
+		return c.AgeSecretKeySource
+	}
+
+	return ageSecretKeySourceConfig
+}
+
 // Config represents the application configuration for Vaultik.
 // It defines all settings for backup operations, including source directories,
 // encryption recipients, storage configuration, and performance tuning parameters.
@@ -144,6 +164,11 @@ func (c *Config) SnapshotNames() []string {
 type Config struct {
 	AgeRecipients []string `yaml:"age_recipients"`
 	AgeSecretKey  string   `yaml:"age_secret_key"`
+	// AgeSecretKeySource names where AgeSecretKey was configured
+	// ("VAULTIK_AGE_SECRET_KEY" or "age_secret_key") so a later parse
+	// failure can name the source without echoing the secret value. It is
+	// set by Load and never read from or written to the config file.
+	AgeSecretKeySource string `yaml:"-"`
 	BlobSizeLimit      Size   `yaml:"blob_size_limit"`
 	ChunkSize          Size   `yaml:"chunk_size"`
 	// Exclude holds global excludes applied to all snapshots.
@@ -254,10 +279,7 @@ func Load(path string) (*Config, error) {
 		cfg.IndexPath = expandTilde(envIndexPath)
 	}
 
-	// Check for environment variable override for AgeSecretKey
-	if envAgeSecretKey := os.Getenv("VAULTIK_AGE_SECRET_KEY"); envAgeSecretKey != "" {
-		cfg.AgeSecretKey = extractAgeSecretKey(envAgeSecretKey)
-	}
+	cfg.setAgeSecretKey()
 
 	// Get hostname if not set
 	if cfg.Hostname == "" {
@@ -379,6 +401,21 @@ func validateAgeRecipient(recipient string) error {
 	return nil
 }
 
+// setAgeSecretKey records the age secret key and where it came from. The
+// value is stored raw and parsed only where decryption happens
+// (internal/vaultik), so backup, list and prune keep working whatever the
+// field holds. The environment variable overrides the config-file field.
+func (c *Config) setAgeSecretKey() {
+	if c.AgeSecretKey != "" {
+		c.AgeSecretKeySource = ageSecretKeySourceConfig
+	}
+
+	if env := os.Getenv("VAULTIK_AGE_SECRET_KEY"); env != "" {
+		c.AgeSecretKey = env
+		c.AgeSecretKeySource = ageSecretKeySourceEnv
+	}
+}
+
 // validateStorage validates storage configuration.
 // If StorageURL is set, it takes precedence. S3 URLs require credentials.
 // File URLs don't require any S3 configuration.
@@ -435,22 +472,6 @@ func (c *Config) validateStorageURL() error {
 	}
 }
 
-// extractAgeSecretKey extracts the AGE-SECRET-KEY from the input using
-// the age library's parser, which handles comments and whitespace.
-func extractAgeSecretKey(input string) string {
-	identities, err := age.ParseIdentities(strings.NewReader(input))
-	if err != nil || len(identities) == 0 {
-		// Fall back to trimmed input if parsing fails
-		return strings.TrimSpace(input)
-	}
-	// Return the string representation of the first identity
-	if id, ok := identities[0].(*age.X25519Identity); ok {
-		return id.String()
-	}
-
-	return strings.TrimSpace(input)
-}
-
 // Module exports the config module for fx dependency injection.
 // It provides the Config type to other modules in the application.
 //

internal/config/config_test.go

@@ -1,4 +1,4 @@
-package config //nolint:testpackage // exercises unexported extractAgeSecretKey
+package config //nolint:testpackage // exercises unexported source constants
 
 import (
 	"errors"
@@ -298,53 +298,31 @@ func TestValidateAgeRecipients(t *testing.T) {
 	}
 }
 
-// TestExtractAgeSecretKey tests extraction of AGE-SECRET-KEY from various inputs
-func TestExtractAgeSecretKey(t *testing.T) {
+// TestAgeSecretKeySourceName checks the name reported for the configured
+// age secret key: the recorded source when Load set one, and the
+// config-file field name for a Config built directly (as in tests).
+func TestAgeSecretKeySourceName(t *testing.T) {
 	t.Parallel()
 
 	tests := []struct {
 		name   string
-		input    string
-		expected string
+		source string
+		want   string
 	}{
 		{
-			name:     "plain key",
-			input:    testIntegrationAgePrivateKey,
-			expected: testIntegrationAgePrivateKey,
+			name:   "unset defaults to config field",
+			source: "",
+			want:   ageSecretKeySourceConfig,
 		},
 		{
-			name:     "key with trailing newline",
-			input:    testIntegrationAgePrivateKey + "\n",
-			expected: testIntegrationAgePrivateKey,
+			name:   "environment source",
+			source: ageSecretKeySourceEnv,
+			want:   ageSecretKeySourceEnv,
 		},
 		{
-			name: "full age-keygen output",
-			input: "# created: 2025-01-14T12:00:00Z\n" +
-				"# public key: " + testIntegrationAgePublicKey + "\n" +
-				testIntegrationAgePrivateKey + "\n",
-			expected: testIntegrationAgePrivateKey,
-		},
-		{
-			name: "age-keygen output with extra blank lines",
-			input: "# created: 2025-01-14T12:00:00Z\n" +
-				"# public key: " + testIntegrationAgePublicKey + "\n\n" +
-				testIntegrationAgePrivateKey + "\n\n",
-			expected: testIntegrationAgePrivateKey,
-		},
-		{
-			name:     "key with leading whitespace",
-			input:    "  " + testIntegrationAgePrivateKey + "  ",
-			expected: testIntegrationAgePrivateKey,
-		},
-		{
-			name:     "empty input",
-			input:    "",
-			expected: "",
-		},
-		{
-			name:     "only comments",
-			input:    "# this is a comment\n# another comment",
-			expected: "# this is a comment\n# another comment",
+			name:   "config-file source",
+			source: ageSecretKeySourceConfig,
+			want:   ageSecretKeySourceConfig,
 		},
 	}
 
@@ -352,10 +330,9 @@ func TestExtractAgeSecretKey(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 
-			result := extractAgeSecretKey(tt.input)
-			if result != tt.expected {
-				t.Errorf("extractAgeSecretKey(%q) = %q, want %q",
-					tt.input, result, tt.expected)
+			cfg := &Config{AgeSecretKeySource: tt.source}
+			if got := cfg.AgeSecretKeySourceName(); got != tt.want {
+				t.Errorf("AgeSecretKeySourceName() = %q, want %q", got, tt.want)
 			}
 		})
 	}

internal/vaultik/blob_fetch.go

@@ -74,14 +74,15 @@ func (h *hashVerifyReader) Close() error {
 // The hash is verified when the returned reader is closed (after fully reading).
 // This avoids buffering the entire blob in memory.
 func (v *Vaultik) FetchAndDecryptBlob(
-	ctx context.Context, blobHash string, expectedSize int64, identity age.Identity,
+	ctx context.Context, blobHash string, expectedSize int64,
+	identities ...age.Identity,
 ) (io.ReadCloser, error) {
 	rc, _, err := v.FetchBlob(ctx, blobHash, expectedSize)
 	if err != nil {
 		return nil, err
 	}
 
-	reader, err := blobgen.NewReader(rc, identity)
+	reader, err := blobgen.NewReader(rc, identities...)
 	if err != nil {
 		_ = rc.Close()
 

internal/vaultik/restore.go

@@ -30,8 +30,13 @@ var (
 	errDecryptionKeyRequired = errors.New(
 		"decryption key required for restore\n\n" +
 			"Set the VAULTIK_AGE_SECRET_KEY environment variable to your " +
-			"age private key:\n" +
-			"  export VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...'")
+			"age private key file:\n" +
+			"  export VAULTIK_AGE_SECRET_KEY=\"$(cat vaultik_backup_private_key.txt)\"")
+	// errInvalidAgeSecretKey is returned when the configured key does not
+	// parse as any age identity. It names the source but never the value,
+	// which is secret, so the message is safe to print and log.
+	errInvalidAgeSecretKey = errors.New(
+		"configured age secret key holds no usable age identity")
 	errBlobMissingFromIndex     = errors.New("blob hash missing from blob index")
 	errChunkNotInAnyBlob        = errors.New("chunk not found in any blob")
 	errBlobIDNotInHashIndex     = errors.New("blob id missing from hash index")
@@ -97,7 +102,7 @@ type RestoreResult struct {
 func (v *Vaultik) Restore(opts *RestoreOptions) error {
 	startTime := time.Now()
 
-	identity, err := v.prepareRestoreIdentity()
+	identities, err := v.restoreIdentities()
 	if err != nil {
 		return err
 	}
@@ -111,7 +116,7 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 	// Step 1: Download and decrypt the snapshot metadata database
 	log.Info("Downloading snapshot metadata...")
 
-	tempDB, tempDir, err := v.downloadSnapshotDB(opts.SnapshotID, identity)
+	tempDB, tempDir, err := v.downloadSnapshotDB(opts.SnapshotID, identities)
 	if err != nil {
 		return fmt.Errorf("downloading snapshot database: %w", err)
 	}
@@ -160,7 +165,7 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 	}
 
 	// Step 5: Restore files
-	result, err := v.restoreAllFiles(files, repos, opts, identity, chunkToBlobMap)
+	result, err := v.restoreAllFiles(files, repos, opts, identities, chunkToBlobMap)
 	if err != nil {
 		return err
 	}
@@ -221,21 +226,28 @@ func (v *Vaultik) finishRestore(
 	return nil
 }
 
-// prepareRestoreIdentity validates that an age secret key is configured
-// and parses it.
-//
-//nolint:ireturn // age.Identity is the decryption abstraction by design
-func (v *Vaultik) prepareRestoreIdentity() (age.Identity, error) {
+// restoreIdentities parses the configured age secret key once into every
+// identity it contains. The value may be a single key line or a whole
+// age-keygen file with several identities; all of them are returned so
+// blobgen (via age.Decrypt) can read a blob encrypted to any of their
+// recipients. This is the first step of both restore and deep verify, so
+// a missing or unparseable key fails before anything is downloaded. The
+// error names the configuration source but never the key value.
+func (v *Vaultik) restoreIdentities() ([]age.Identity, error) {
 	if v.Config.AgeSecretKey == "" {
 		return nil, errDecryptionKeyRequired
 	}
 
-	identity, err := age.ParseX25519Identity(v.Config.AgeSecretKey)
+	// age.ParseIdentities skips comment and blank lines and rejects a
+	// malformed key. Its error can quote the offending line, so it is not
+	// wrapped here — that would leak the secret into the message.
+	identities, err := age.ParseIdentities(strings.NewReader(v.Config.AgeSecretKey))
 	if err != nil {
-		return nil, fmt.Errorf("parsing age secret key: %w", err)
+		return nil, fmt.Errorf("%w (source: %s)",
+			errInvalidAgeSecretKey, v.Config.AgeSecretKeySourceName())
 	}
 
-	return identity, nil
+	return identities, nil
 }
 
 // restoreAllFiles processes files in blob-locality order: drain every
@@ -248,7 +260,7 @@ func (v *Vaultik) restoreAllFiles(
 	files []*database.File,
 	repos *database.Repositories,
 	opts *RestoreOptions,
-	identity age.Identity,
+	identities []age.Identity,
 	chunkToBlobMap map[string]*database.BlobChunk,
 ) (*RestoreResult, error) {
 	result := &RestoreResult{}
@@ -302,7 +314,7 @@ func (v *Vaultik) restoreAllFiles(
 		ctx:            v.ctx,
 		repos:          repos,
 		opts:           opts,
-		identity:       identity,
+		identities:     identities,
 		chunkToBlobMap: chunkToBlobMap,
 		blobByHash:     blobByHash,
 		blobIDToHash:   blobIDToHash,
@@ -616,7 +628,7 @@ func (v *Vaultik) handleRestoreVerification(
 // for a remote-only snapshot) is used as-is, so a host with no local
 // index can restore the snapshots it can only see on the store.
 func (v *Vaultik) downloadSnapshotDB(
-	snapshotID string, identity age.Identity,
+	snapshotID string, identities []age.Identity,
 ) (*database.DB, string, error) {
 	remoteKey, err := v.resolveSnapshotRemoteKey(snapshotID)
 	if err != nil {
@@ -643,7 +655,7 @@ func (v *Vaultik) downloadSnapshotDB(
 		"size", ubytes(int64(len(encryptedData))))
 
 	// Decrypt and decompress using blobgen.Reader
-	blobReader, err := blobgen.NewReader(bytes.NewReader(encryptedData), identity)
+	blobReader, err := blobgen.NewReader(bytes.NewReader(encryptedData), identities...)
 	if err != nil {
 		return nil, "", fmt.Errorf("creating decryption reader: %w", err)
 	}
@@ -833,7 +845,7 @@ type restoreSession struct {
 	ctx            context.Context //nolint:containedctx // per-restore state by design
 	repos          *database.Repositories
 	opts           *RestoreOptions
-	identity       age.Identity
+	identities     []age.Identity
 	chunkToBlobMap map[string]*database.BlobChunk
 	blobByHash     map[string]*database.Blob
 	blobIDToHash   map[string]string
@@ -1195,7 +1207,7 @@ func (s *restoreSession) downloadBlobToCache(
 	start := time.Now()
 
 	t0 := time.Now()
-	rc, err := s.v.FetchAndDecryptBlob(s.ctx, blobHash, expectedSize, s.identity)
+	rc, err := s.v.FetchAndDecryptBlob(s.ctx, blobHash, expectedSize, s.identities...)
 	fetchSetupDur := time.Since(t0)
 
 	if err != nil {

internal/vaultik/restore_identity_test.go

@@ -0,0 +1,108 @@
+package vaultik //nolint:testpackage // exercises unexported restoreIdentities
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	"filippo.io/age"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/blobgen"
+	"sneak.berlin/go/vaultik/internal/config"
+)
+
+// encryptBlobTo returns a blobgen blob of plaintext encrypted to exactly
+// one recipient, so a decryptor succeeds only if it holds that recipient's
+// identity.
+func encryptBlobTo(t *testing.T, recipient string, plaintext []byte) []byte {
+	t.Helper()
+
+	var buf bytes.Buffer
+
+	writer, err := blobgen.NewWriter(&buf, 1, []string{recipient})
+	require.NoError(t, err)
+
+	_, err = writer.Write(plaintext)
+	require.NoError(t, err)
+	require.NoError(t, writer.Close())
+
+	return buf.Bytes()
+}
+
+// decryptBlobWith reads a blob back through the identities and returns its
+// plaintext.
+func decryptBlobWith(t *testing.T, blob []byte, identities []age.Identity) []byte {
+	t.Helper()
+
+	reader, err := blobgen.NewReader(bytes.NewReader(blob), identities...)
+	require.NoError(t, err)
+
+	plaintext, err := io.ReadAll(reader)
+	require.NoError(t, err)
+	require.NoError(t, reader.Close())
+
+	return plaintext
+}
+
+// TestRestoreIdentitiesAcceptsEveryIdentity proves a key file holding two
+// identities yields both, so a blob encrypted only to the second
+// recipient — the one the previous single-identity parse dropped — still
+// decrypts.
+func TestRestoreIdentitiesAcceptsEveryIdentity(t *testing.T) {
+	t.Parallel()
+
+	first, err := age.GenerateX25519Identity()
+	require.NoError(t, err)
+
+	second, err := age.GenerateX25519Identity()
+	require.NoError(t, err)
+
+	// A whole age-keygen-style file: comment lines plus two identity lines.
+	keyFile := "# public key: " + first.Recipient().String() + "\n" +
+		first.String() + "\n" +
+		"# public key: " + second.Recipient().String() + "\n" +
+		second.String() + "\n"
+
+	v := &Vaultik{Config: &config.Config{AgeSecretKey: keyFile}}
+
+	identities, err := v.restoreIdentities()
+	require.NoError(t, err)
+	require.Len(t, identities, 2)
+
+	plaintext := []byte("payload encrypted only to the second identity")
+	blob := encryptBlobTo(t, second.Recipient().String(), plaintext)
+
+	require.Equal(t, plaintext, decryptBlobWith(t, blob, identities))
+}
+
+// TestRestoreIdentitiesAcceptsTrailingNewline mirrors a YAML
+// age_secret_key value that carries a trailing newline: it must still
+// parse to its one identity and decrypt a blob encrypted to it.
+func TestRestoreIdentitiesAcceptsTrailingNewline(t *testing.T) {
+	t.Parallel()
+
+	id, err := age.GenerateX25519Identity()
+	require.NoError(t, err)
+
+	v := &Vaultik{Config: &config.Config{AgeSecretKey: id.String() + "\n"}}
+
+	identities, err := v.restoreIdentities()
+	require.NoError(t, err)
+	require.Len(t, identities, 1)
+
+	plaintext := []byte("value with a trailing newline")
+	blob := encryptBlobTo(t, id.Recipient().String(), plaintext)
+
+	require.Equal(t, plaintext, decryptBlobWith(t, blob, identities))
+}
+
+// TestRestoreIdentitiesMissingKey reports the dedicated missing-key error
+// rather than a parse failure, so the user is told to set the key.
+func TestRestoreIdentitiesMissingKey(t *testing.T) {
+	t.Parallel()
+
+	v := &Vaultik{Config: &config.Config{}}
+
+	_, err := v.restoreIdentities()
+	require.ErrorIs(t, err, errDecryptionKeyRequired)
+}

internal/vaultik/restore_malformed_key_test.go

@@ -0,0 +1,44 @@
+package vaultik_test
+
+import (
+	"context"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/config"
+	"sneak.berlin/go/vaultik/internal/ui"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// TestRestoreRejectsMalformedKeyBeforeDownload verifies that a malformed
+// age secret key stops restore at the parse step: nothing is fetched from
+// the store, and the error does not echo the key value (which is secret).
+func TestRestoreRejectsMalformedKeyBeforeDownload(t *testing.T) {
+	t.Parallel()
+
+	const malformed = "this-is-not-a-valid-age-key"
+
+	mock := NewMockStorer()
+
+	v := &vaultik.Vaultik{
+		Config:  &config.Config{AgeSecretKey: malformed},
+		Storage: mock,
+		Stdout:  io.Discard,
+		Stderr:  io.Discard,
+		UI:      ui.NewWithColor(io.Discard, false),
+	}
+	v.SetContext(context.Background())
+
+	err := v.Restore(&vaultik.RestoreOptions{
+		SnapshotID: "any-snapshot",
+		TargetDir:  t.TempDir(),
+	})
+	require.Error(t, err)
+	require.NotContains(t, err.Error(), malformed,
+		"error must not echo the key value")
+	require.Contains(t, err.Error(), "age_secret_key",
+		"error should name the configuration source")
+	require.Empty(t, mock.GetCalls(),
+		"a malformed key must fail before anything is fetched")
+}

internal/vaultik/verify.go

@@ -94,11 +94,10 @@ func (v *Vaultik) RunDeepVerify(snapshotID string, opts *VerifyOptions) error {
 	}
 
 	// Parse the age secret key once, the same way restore does, and reuse
-	// the identity for the database and every blob.
-	identity, err := v.prepareRestoreIdentity()
+	// the identities for the database and every blob.
+	identities, err := v.restoreIdentities()
 	if err != nil {
-		return v.deepVerifyFailure(result, opts,
-			fmt.Sprintf("parsing age secret key: %v", err), err)
+		return v.deepVerifyFailure(result, opts, err.Error(), err)
 	}
 
 	log.Info("Starting snapshot verification", "snapshot_id", snapshotID, "mode", "deep")
@@ -108,7 +107,7 @@ func (v *Vaultik) RunDeepVerify(snapshotID string, opts *VerifyOptions) error {
 	}
 
 	manifest, tempDB, dbBlobs, err := v.loadVerificationData(
-		snapshotID, opts, result, identity)
+		snapshotID, opts, result, identities)
 	if err != nil {
 		return err
 	}
@@ -129,7 +128,7 @@ func (v *Vaultik) RunDeepVerify(snapshotID string, opts *VerifyOptions) error {
 	result.TotalSize = totalSize
 
 	err = v.runVerificationSteps(
-		manifest, dbBlobs, tempDB, opts, result, totalSize, identity)
+		manifest, dbBlobs, tempDB, opts, result, totalSize, identities)
 	if err != nil {
 		return err
 	}
@@ -154,7 +153,7 @@ func (v *Vaultik) RunDeepVerify(snapshotID string, opts *VerifyOptions) error {
 // loadVerificationData downloads manifest, database, and blob list for verification
 func (v *Vaultik) loadVerificationData(
 	snapshotID string, opts *VerifyOptions, result *VerifyResult,
-	identity age.Identity,
+	identities []age.Identity,
 ) (*snapshot.Manifest, *tempDB, []snapshot.BlobInfo, error) {
 	// Resolve the identifier to the snapshot's remote key. A human ID is
 	// hashed; a remote key (or its abbreviation, as printed for a
@@ -191,7 +190,8 @@ func (v *Vaultik) loadVerificationData(
 		v.stdoutf("Downloading and decrypting database...\n")
 	}
 
-	tdb, err := v.downloadVerifiedSnapshotDB(snapshotID, remoteKey, opts, result, identity)
+	tdb, err := v.downloadVerifiedSnapshotDB(
+		snapshotID, remoteKey, opts, result, identities)
 	if err != nil {
 		return nil, nil, nil, err
 	}
@@ -230,7 +230,7 @@ func (v *Vaultik) loadVerificationData(
 // identity so nothing is left on disk.
 func (v *Vaultik) downloadVerifiedSnapshotDB(
 	snapshotID, remoteKey string, opts *VerifyOptions, result *VerifyResult,
-	identity age.Identity,
+	identities []age.Identity,
 ) (*tempDB, error) {
 	dbPath := fmt.Sprintf("metadata/%s/db.zst.age", remoteKey)
 	log.Info("Downloading encrypted database", "path", dbPath)
@@ -244,7 +244,7 @@ func (v *Vaultik) downloadVerifiedSnapshotDB(
 
 	defer func() { _ = dbReader.Close() }()
 
-	tdb, err := v.decryptAndLoadDatabase(dbReader, identity)
+	tdb, err := v.decryptAndLoadDatabase(dbReader, identities)
 	if err != nil {
 		return nil, v.deepVerifyFailure(result, opts,
 			fmt.Sprintf("failed to decrypt database: %v", err),
@@ -270,7 +270,7 @@ func (v *Vaultik) runVerificationSteps(
 	opts *VerifyOptions,
 	result *VerifyResult,
 	totalSize int64,
-	identity age.Identity,
+	identities []age.Identity,
 ) error {
 	if !opts.JSON {
 		v.stdoutf("Verifying manifest against database...\n")
@@ -297,7 +297,7 @@ func (v *Vaultik) runVerificationSteps(
 			len(dbBlobs), ubytes(totalSize))
 	}
 
-	err = v.performDeepVerificationFromDB(dbBlobs, tdb.db.Conn(), opts, identity)
+	err = v.performDeepVerificationFromDB(dbBlobs, tdb.db.Conn(), opts, identities)
 	if err != nil {
 		return v.deepVerifyFailure(result, opts, err.Error(), err)
 	}
@@ -325,10 +325,10 @@ func (t *tempDB) Close() error {
 // from the encrypted stream. It reads through the same blobgen reader restore
 // uses, streaming the decrypted, decompressed database to a temp file.
 func (v *Vaultik) decryptAndLoadDatabase(
-	reader io.ReadCloser, identity age.Identity,
+	reader io.ReadCloser, identities []age.Identity,
 ) (*tempDB, error) {
 	// Decrypt and decompress through the shared blobgen reader.
-	blobReader, err := blobgen.NewReader(reader, identity)
+	blobReader, err := blobgen.NewReader(reader, identities...)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create decryption reader: %w", err)
 	}
@@ -389,7 +389,7 @@ func (v *Vaultik) decryptAndLoadDatabase(
 
 // verifyBlob downloads and verifies a single blob
 func (v *Vaultik) verifyBlob(
-	blobInfo snapshot.BlobInfo, db *sql.DB, identity age.Identity,
+	blobInfo snapshot.BlobInfo, db *sql.DB, identities []age.Identity,
 ) error {
 	// Download blob using shared fetch method
 	reader, _, err := v.FetchBlob(v.ctx, blobInfo.Hash, blobInfo.CompressedSize)
@@ -403,7 +403,7 @@ func (v *Vaultik) verifyBlob(
 	// the plaintext as it is read. A blob's hash — its remote name — is the
 	// double SHA-256 of that plaintext (see blobgen.DoubleSHA256), not of the
 	// encrypted bytes.
-	blobReader, err := blobgen.NewReader(reader, identity)
+	blobReader, err := blobgen.NewReader(reader, identities...)
 	if err != nil {
 		return fmt.Errorf("failed to create blob reader: %w", err)
 	}
@@ -687,7 +687,7 @@ func (v *Vaultik) verifyBlobExistenceFromDB(blobs []snapshot.BlobInfo) error {
 // each blob using the database as source.
 func (v *Vaultik) performDeepVerificationFromDB(
 	blobs []snapshot.BlobInfo, db *sql.DB, opts *VerifyOptions,
-	identity age.Identity,
+	identities []age.Identity,
 ) error {
 	// Calculate total bytes for ETA
 	var totalBytesExpected int64
@@ -705,7 +705,7 @@ func (v *Vaultik) performDeepVerificationFromDB(
 
 	for i, blobInfo := range blobs {
 		// Verify individual blob
-		err := v.verifyBlob(blobInfo, db, identity)
+		err := v.verifyBlob(blobInfo, db, identities)
 		if err != nil {
 			return fmt.Errorf("blob %s verification failed: %w", blobInfo.Hash, err)
 		}