Golang文件加密解密实现方法

func encryptFile(inputPath, outputPath string, key []byte) error {
    plaintext, err := os.ReadFile(inputPath)
    if err != nil {
        return err
    }
block, err := aes.NewCipher(key)
if err != nil {
    return err
}

// 生成随机IV
iv := make([]byte, aes.BlockSize)
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
    return err
}

// 填充
plaintext = pkcs7Padding(plaintext, aes.BlockSize)

ciphertext := make([]byte, len(plaintext))
mode := cipher.NewCBCEncrypter(block, iv)
mode.CryptBlocks(ciphertext, plaintext)

// 写入IV + 密文
file, err := os.Create(outputPath)
if err != nil {
    return err
}
defer file.Close()

file.Write(iv)
file.Write(ciphertext)
return nil
}
func pkcs7Padding(data []byte, blockSize int) []byte {
padding := blockSize - len(data)%blockSize
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
return append(data, padtext...)
}

func decryptFile(inputPath, outputPath string, key []byte) error {
    data, err := os.ReadFile(inputPath)
    if err != nil {
        return err
    }
block, err := aes.NewCipher(key)
if err != nil {
    return err
}

if len(data) < aes.BlockSize {
    return errors.New("密文太短")
}

iv := data[:aes.BlockSize]
ciphertext := data[aes.BlockSize:]

if len(ciphertext)%aes.BlockSize != 0 {
    return errors.New("密文长度不合法")
}

mode := cipher.NewCBCDecrypter(block, iv)
plaintext := make([]byte, len(ciphertext))
mode.CryptBlocks(plaintext, ciphertext)

// 去除PKCS7填充
plaintext, err = pkcs7Unpad(plaintext)
if err != nil {
    return err
}

return os.WriteFile(outputPath, plaintext, 0644)
}
func pkcs7Unpad(data []byte) ([]byte, error) {
length := len(data)
if length == 0 {
return nil, errors.New("空数据")
}
unpad := int(data[length-1])
if unpad > length {
return nil, errors.New("无效填充")
}
return data[:length-unpad], nil
}

key := []byte("your-32-byte-secret-key-here!!!") // 必须是32字节
// 加密
err := encryptFile("test.txt", "encrypted.dat", key)
if err != nil {
log.Fatal(err)
}
// 解密
err = decryptFile("encrypted.dat", "decrypted.txt", key)
if err != nil {
log.Fatal(err)
}