96 lines
2.3 KiB
Go
96 lines
2.3 KiB
Go
package repository
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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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"encoding/base64"
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"encoding/hex"
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"fmt"
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"io"
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"github.com/Wei-Shaw/sub2api/internal/config"
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"github.com/Wei-Shaw/sub2api/internal/service"
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)
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// AESEncryptor implements SecretEncryptor using AES-256-GCM
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type AESEncryptor struct {
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key []byte
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}
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// NewAESEncryptor creates a new AES encryptor
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func NewAESEncryptor(cfg *config.Config) (service.SecretEncryptor, error) {
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key, err := hex.DecodeString(cfg.Totp.EncryptionKey)
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if err != nil {
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return nil, fmt.Errorf("invalid totp encryption key: %w", err)
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}
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if len(key) != 32 {
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return nil, fmt.Errorf("totp encryption key must be 32 bytes (64 hex chars), got %d bytes", len(key))
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}
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return &AESEncryptor{key: key}, nil
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}
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// Encrypt encrypts plaintext using AES-256-GCM
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// Output format: base64(nonce + ciphertext + tag)
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func (e *AESEncryptor) Encrypt(plaintext string) (string, error) {
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block, err := aes.NewCipher(e.key)
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if err != nil {
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return "", fmt.Errorf("create cipher: %w", err)
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}
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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", fmt.Errorf("create gcm: %w", err)
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}
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// Generate a random nonce
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nonce := make([]byte, gcm.NonceSize())
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return "", fmt.Errorf("generate nonce: %w", err)
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}
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// Encrypt the plaintext
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// Seal appends the ciphertext and tag to the nonce
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ciphertext := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
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// Encode as base64
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return base64.StdEncoding.EncodeToString(ciphertext), nil
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}
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// Decrypt decrypts ciphertext using AES-256-GCM
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func (e *AESEncryptor) Decrypt(ciphertext string) (string, error) {
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// Decode from base64
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data, err := base64.StdEncoding.DecodeString(ciphertext)
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if err != nil {
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return "", fmt.Errorf("decode base64: %w", err)
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}
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block, err := aes.NewCipher(e.key)
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if err != nil {
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return "", fmt.Errorf("create cipher: %w", err)
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}
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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", fmt.Errorf("create gcm: %w", err)
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}
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nonceSize := gcm.NonceSize()
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if len(data) < nonceSize {
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return "", fmt.Errorf("ciphertext too short")
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}
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// Extract nonce and ciphertext
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nonce, ciphertextData := data[:nonceSize], data[nonceSize:]
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// Decrypt
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plaintext, err := gcm.Open(nil, nonce, ciphertextData, nil)
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if err != nil {
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return "", fmt.Errorf("decrypt: %w", err)
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}
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return string(plaintext), nil
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}
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