enc and decryp

bothway.go

// Decrypt decrypts the ciphertext using AES with the given key
func Decrypt(ciphertext, key string) (string, error) {
	// Convert the key and ciphertext to byte arrays
	keyBytes := []byte(key)
	ciphertextBytes, err := base64.StdEncoding.DecodeString(ciphertext)
	if err != nil {
		return "", err
	}
	// Create a new AES cipher
	block, err := aes.NewCipher(keyBytes)
	if err != nil {
		return "", err
	}
	// Create a GCM mode cipher
	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return "", err
	}
	// Separate nonce and ciphertext
	nonce, ciphertextBytes := ciphertextBytes[:gcm.NonceSize()], ciphertextBytes[gcm.NonceSize():]
	// Decrypt the ciphertext
	decrypted, err := gcm.Open(nil, nonce, ciphertextBytes, nil)
	if err != nil {
		return "", err
	}
	// Remove padding
	padding := decrypted[len(decrypted)-1]
	if int(padding) > aes.BlockSize || int(padding) > len(decrypted) {
		return "", fmt.Errorf("invalid padding")
	}
	decrypted = decrypted[:len(decrypted)-int(padding)]
	return string(decrypted), nil
}

// Encrypt encrypts the plaintext using AES with the given key
func Encrypt(plaintext, key string) (string, error) {
	// Convert the key to a byte array
	keyBytes := []byte(key)
	// Create a new AES cipher
	block, err := aes.NewCipher(keyBytes)
	if err != nil {
		return "", err
	}
	// Ensure plaintext is a multiple of the block size
	padding := aes.BlockSize - len(plaintext)%aes.BlockSize
	padtext := []byte(plaintext)
	padtext = append(padtext, bytes.Repeat([]byte{byte(padding)}, padding)...)
	// Create a GCM mode cipher
	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return "", err
	}
	// Generate a nonce
	nonce := make([]byte, gcm.NonceSize())
	// Encrypt the plaintext
	ciphertext := gcm.Seal(nonce, nonce, padtext, nil)
	// Return base64 encoded ciphertext
	return base64.StdEncoding.EncodeToString(ciphertext), nil
}