swanadiva
611b794fc7
- pkg/crypto: AES-256-GCM encryption with PBKDF2 key derivation - 100k iterations, 16-byte salt, SHA-256 - Encrypt/Decrypt/IsEncrypted/HashPassword - Storage layer encryption: - JSONStorage.SetPassword() enables transparent encrypt/decrypt - readJSON auto-decrypts, replace* auto-encrypts - pkg/knownhosts: TOFU host key verification - Verify/Add/Remove host keys - HostKeyCallback for SSH config - SSH client security: - SetHostKeyCallback() replaces InsecureIgnoreHostKey() - SetPassphraseCallback() for encrypted private keys - getKeySigner() tries passphrase on encrypted keys - Models: AppConfig gains EncryptionEnabled, PasswordHash, KnownHostsFile
123 lines
2.8 KiB
Go
123 lines
2.8 KiB
Go
package crypto
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"errors"
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"io"
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"golang.org/x/crypto/pbkdf2"
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)
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const (
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KeyLength = 32 // AES-256
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SaltLength = 16
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Iterations = 100000
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)
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var (
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ErrInvalidPassword = errors.New("invalid password")
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ErrDecryptionFailed = errors.New("decryption failed — wrong password or corrupted data")
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)
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// DeriveKey derives an AES-256 key from a password using PBKDF2
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func DeriveKey(password string, salt []byte) []byte {
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return pbkdf2.Key([]byte(password), salt, Iterations, KeyLength, sha256.New)
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}
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// Encrypt encrypts plaintext using AES-256-GCM with a password
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func Encrypt(plaintext []byte, password string) (string, error) {
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salt := make([]byte, SaltLength)
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if _, err := io.ReadFull(rand.Reader, salt); err != nil {
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return "", err
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}
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key := DeriveKey(password, salt)
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block, err := aes.NewCipher(key)
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if err != nil {
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return "", err
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}
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aesGCM, err := cipher.NewGCM(block)
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if err != nil {
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return "", err
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}
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nonce := make([]byte, aesGCM.NonceSize())
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return "", err
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}
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ciphertext := aesGCM.Seal(nil, nonce, plaintext, nil)
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// Format: base64(salt + nonce + ciphertext)
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result := make([]byte, 0, len(salt)+len(nonce)+len(ciphertext))
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result = append(result, salt...)
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result = append(result, nonce...)
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result = append(result, ciphertext...)
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return base64.StdEncoding.EncodeToString(result), nil
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}
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// Decrypt decrypts ciphertext using AES-256-GCM with a password
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func Decrypt(encoded string, password string) ([]byte, error) {
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data, err := base64.StdEncoding.DecodeString(encoded)
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if err != nil {
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return nil, ErrDecryptionFailed
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}
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if len(data) < SaltLength+12 { // 12 = minimum nonce size for GCM
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return nil, ErrDecryptionFailed
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}
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salt := data[:SaltLength]
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data = data[SaltLength:]
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key := DeriveKey(password, salt)
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, ErrDecryptionFailed
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}
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aesGCM, err := cipher.NewGCM(block)
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if err != nil {
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return nil, ErrDecryptionFailed
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}
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nonceSize := aesGCM.NonceSize()
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if len(data) < nonceSize {
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return nil, ErrDecryptionFailed
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}
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nonce := data[:nonceSize]
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ciphertext := data[nonceSize:]
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plaintext, err := aesGCM.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return nil, ErrInvalidPassword
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}
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return plaintext, nil
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}
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// IsEncrypted checks if a string looks like base64-encoded encrypted data
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func IsEncrypted(data string) bool {
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decoded, err := base64.StdEncoding.DecodeString(data)
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if err != nil {
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return false
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}
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// Minimum: 16 (salt) + 12 (nonce) + 16 (min ciphertext) = 44 bytes
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return len(decoded) >= 44
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}
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// HashPassword creates a SHA-256 hash of a password for verification
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func HashPassword(password string) string {
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h := sha256.Sum256([]byte(password))
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return base64.StdEncoding.EncodeToString(h[:])
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}
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