feat: vault service — Argon2id key derivation + AES-256-GCM encrypt/decrypt

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

go.mod

@@ -4,6 +4,7 @@ go 1.26.1
 
 require (
 	github.com/wailsapp/wails/v3 v3.0.0-alpha.74
+	golang.org/x/crypto v0.49.0
 	modernc.org/sqlite v1.46.2
 )
 
@@ -45,10 +46,9 @@ require (
 	github.com/skeema/knownhosts v1.3.2 // indirect
 	github.com/wailsapp/go-webview2 v1.0.23 // indirect
 	github.com/xanzy/ssh-agent v0.3.3 // indirect
-	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/net v0.51.0 // indirect
-	golang.org/x/net v0.49.0 // indirect
 	golang.org/x/sys v0.42.0 // indirect
-	golang.org/x/text v0.33.0 // indirect
+	golang.org/x/text v0.35.0 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
 	modernc.org/libc v1.70.0 // indirect
 	modernc.org/mathutil v1.7.1 // indirect

go.sum

@@ -122,17 +122,17 @@ github.com/wailsapp/wails/v3 v3.0.0-alpha.74/go.mod h1:4saK4A4K9970X+X7RkMwP2lyG
 github.com/xanzy/ssh-agent v0.3.3 h1:+/15pJfg/RsTxqYcX6fHqOXZwwMP+2VyYWJeWM2qQFM=
 github.com/xanzy/ssh-agent v0.3.3/go.mod h1:6dzNDKs0J9rVPHPhaGCukekBHKqfl+L3KghI1Bc68Uw=
 golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
-golang.org/x/crypto v0.47.0 h1:V6e3FRj+n4dbpw86FJ8Fv7XVOql7TEwpHapKoMJ/GO8=
+golang.org/x/crypto v0.49.0 h1:+Ng2ULVvLHnJ/ZFEq4KdcDd/cfjrrjjNSXNzxg0Y4U4=
-golang.org/x/crypto v0.47.0/go.mod h1:ff3Y9VzzKbwSSEzWqJsJVBnWmRwRSHt/6Op5n9bQc4A=
+golang.org/x/crypto v0.49.0/go.mod h1:ErX4dUh2UM+CFYiXZRTcMpEcN8b/1gxEuv3nODoYtCA=
 golang.org/x/exp v0.0.0-20260112195511-716be5621a96 h1:Z/6YuSHTLOHfNFdb8zVZomZr7cqNgTJvA8+Qz75D8gU=
 golang.org/x/exp v0.0.0-20260112195511-716be5621a96/go.mod h1:nzimsREAkjBCIEFtHiYkrJyT+2uy9YZJB7H1k68CXZU=
 golang.org/x/mod v0.33.0 h1:tHFzIWbBifEmbwtGz65eaWyGiGZatSrT9prnU8DbVL8=
 golang.org/x/mod v0.33.0/go.mod h1:swjeQEj+6r7fODbD2cqrnje9PnziFuw4bmLbBZFrQ5w=
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/net v0.49.0 h1:eeHFmOGUTtaaPSGNmjBKpbng9MulQsJURQUAfUwY++o=
+golang.org/x/net v0.51.0 h1:94R/GTO7mt3/4wIKpcR5gkGmRLOuE/2hNGeWq/GBIFo=
-golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=
+golang.org/x/net v0.51.0/go.mod h1:aamm+2QF5ogm02fjy5Bb7CQ0WMt1/WVM7FtyaTLlA9Y=
-golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
-golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200810151505-1b9f1253b3ed/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -145,11 +145,11 @@ golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
 golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.39.0 h1:RclSuaJf32jOqZz74CkPA9qFuVTX7vhLlpfj/IGWlqY=
+golang.org/x/term v0.41.0 h1:QCgPso/Q3RTJx2Th4bDLqML4W6iJiaXFq2/ftQF13YU=
-golang.org/x/term v0.39.0/go.mod h1:yxzUCTP/U+FzoxfdKmLaA0RV1WgE0VY7hXBwKtY/4ww=
+golang.org/x/term v0.41.0/go.mod h1:3pfBgksrReYfZ5lvYM0kSO0LIkAl4Yl2bXOkKP7Ec2A=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.33.0 h1:B3njUFyqtHDUI5jMn1YIr5B0IE2U0qck04r6d4KPAxE=
+golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
-golang.org/x/text v0.33.0/go.mod h1:LuMebE6+rBincTi9+xWTY8TztLzKHc/9C1uBCG27+q8=
+golang.org/x/text v0.35.0/go.mod h1:khi/HExzZJ2pGnjenulevKNX1W67CUy0AsXcNubPGCA=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.42.0 h1:uNgphsn75Tdz5Ji2q36v/nsFSfR/9BRFvqhGBaJGd5k=
 golang.org/x/tools v0.42.0/go.mod h1:Ma6lCIwGZvHK6XtgbswSoWroEkhugApmsXyrUmBhfr0=

internal/vault/service.go

@@ -0,0 +1,95 @@
+package vault
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strings"
+
+	"golang.org/x/crypto/argon2"
+)
+
+const (
+	argonTime    = 3
+	argonMemory  = 64 * 1024
+	argonThreads = 4
+	argonKeyLen  = 32
+)
+
+func DeriveKey(password string, salt []byte) []byte {
+	return argon2.IDKey([]byte(password), salt, argonTime, argonMemory, argonThreads, argonKeyLen)
+}
+
+func GenerateSalt() ([]byte, error) {
+	salt := make([]byte, 32)
+	if _, err := rand.Read(salt); err != nil {
+		return nil, fmt.Errorf("generate salt: %w", err)
+	}
+	return salt, nil
+}
+
+type VaultService struct {
+	key []byte
+}
+
+func NewVaultService(key []byte) *VaultService {
+	return &VaultService{key: key}
+}
+
+func (v *VaultService) Encrypt(plaintext string) (string, error) {
+	block, err := aes.NewCipher(v.key)
+	if err != nil {
+		return "", fmt.Errorf("create cipher: %w", err)
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", fmt.Errorf("create GCM: %w", err)
+	}
+
+	iv := make([]byte, gcm.NonceSize())
+	if _, err := rand.Read(iv); err != nil {
+		return "", fmt.Errorf("generate IV: %w", err)
+	}
+
+	sealed := gcm.Seal(nil, iv, []byte(plaintext), nil)
+
+	return fmt.Sprintf("v1:%s:%s", hex.EncodeToString(iv), hex.EncodeToString(sealed)), nil
+}
+
+func (v *VaultService) Decrypt(encrypted string) (string, error) {
+	parts := strings.SplitN(encrypted, ":", 3)
+	if len(parts) != 3 || parts[0] != "v1" {
+		return "", errors.New("invalid encrypted format: expected v1:{iv}:{sealed}")
+	}
+
+	iv, err := hex.DecodeString(parts[1])
+	if err != nil {
+		return "", fmt.Errorf("decode IV: %w", err)
+	}
+
+	sealed, err := hex.DecodeString(parts[2])
+	if err != nil {
+		return "", fmt.Errorf("decode sealed data: %w", err)
+	}
+
+	block, err := aes.NewCipher(v.key)
+	if err != nil {
+		return "", fmt.Errorf("create cipher: %w", err)
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", fmt.Errorf("create GCM: %w", err)
+	}
+
+	plaintext, err := gcm.Open(nil, iv, sealed, nil)
+	if err != nil {
+		return "", fmt.Errorf("decrypt: %w", err)
+	}
+
+	return string(plaintext), nil
+}

internal/vault/service_test.go

@@ -0,0 +1,104 @@
+package vault
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestDeriveKeyConsistent(t *testing.T) {
+	salt := []byte("test-salt-exactly-32-bytes-long!")
+	key1 := DeriveKey("mypassword", salt)
+	key2 := DeriveKey("mypassword", salt)
+
+	if len(key1) != 32 {
+		t.Errorf("key length = %d, want 32", len(key1))
+	}
+	if string(key1) != string(key2) {
+		t.Error("same password+salt produced different keys")
+	}
+}
+
+func TestDeriveKeyDifferentPasswords(t *testing.T) {
+	salt := []byte("test-salt-exactly-32-bytes-long!")
+	key1 := DeriveKey("password1", salt)
+	key2 := DeriveKey("password2", salt)
+
+	if string(key1) == string(key2) {
+		t.Error("different passwords produced same key")
+	}
+}
+
+func TestEncryptDecryptRoundTrip(t *testing.T) {
+	key := DeriveKey("testpassword", []byte("test-salt-exactly-32-bytes-long!"))
+	vs := NewVaultService(key)
+
+	plaintext := "super-secret-ssh-key-data"
+	encrypted, err := vs.Encrypt(plaintext)
+	if err != nil {
+		t.Fatalf("Encrypt() error: %v", err)
+	}
+
+	if !strings.HasPrefix(encrypted, "v1:") {
+		t.Errorf("encrypted does not start with v1: prefix: %q", encrypted[:10])
+	}
+
+	decrypted, err := vs.Decrypt(encrypted)
+	if err != nil {
+		t.Fatalf("Decrypt() error: %v", err)
+	}
+
+	if decrypted != plaintext {
+		t.Errorf("Decrypt() = %q, want %q", decrypted, plaintext)
+	}
+}
+
+func TestEncryptProducesDifferentCiphertexts(t *testing.T) {
+	key := DeriveKey("testpassword", []byte("test-salt-exactly-32-bytes-long!"))
+	vs := NewVaultService(key)
+
+	enc1, _ := vs.Encrypt("same-data")
+	enc2, _ := vs.Encrypt("same-data")
+
+	if enc1 == enc2 {
+		t.Error("two encryptions of same data produced identical ciphertext (IV reuse)")
+	}
+}
+
+func TestDecryptWrongKey(t *testing.T) {
+	key1 := DeriveKey("password1", []byte("test-salt-exactly-32-bytes-long!"))
+	key2 := DeriveKey("password2", []byte("test-salt-exactly-32-bytes-long!"))
+
+	vs1 := NewVaultService(key1)
+	vs2 := NewVaultService(key2)
+
+	encrypted, _ := vs1.Encrypt("secret")
+	_, err := vs2.Decrypt(encrypted)
+	if err == nil {
+		t.Error("Decrypt() with wrong key should return error")
+	}
+}
+
+func TestDecryptInvalidFormat(t *testing.T) {
+	key := DeriveKey("test", []byte("test-salt-exactly-32-bytes-long!"))
+	vs := NewVaultService(key)
+
+	_, err := vs.Decrypt("not-valid-format")
+	if err == nil {
+		t.Error("Decrypt() with invalid format should return error")
+	}
+}
+
+func TestGenerateSalt(t *testing.T) {
+	salt1, err := GenerateSalt()
+	if err != nil {
+		t.Fatalf("GenerateSalt() error: %v", err)
+	}
+	if len(salt1) != 32 {
+		t.Errorf("salt length = %d, want 32", len(salt1))
+	}
+
+	salt2, _ := GenerateSalt()
+	if string(salt1) == string(salt2) {
+		t.Error("two calls to GenerateSalt produced identical salt")
+	}
+}