go中加解密

func PKCS7Padding(ciphertext []byte, blockSize int) []byte {
    padding := blockSize - len(ciphertext)%blockSize
    //Repeat()函数的功能是把切片[]byte{byte(padding)}复制padding个，然后合并成新的字节切片返回
    padtext := bytes.Repeat([]byte{byte(padding)}, padding)
    return append(ciphertext, padtext...)
}

  //填充的反向操作，删除填充字符串
  func PKCS7UnPadding(origData []byte) ([]byte, error) {
      //获取数据长度
      length := len(origData)
      if length == 0 {
          return nil, errors.New("加密字符串错误！")
      } else {
          //获取填充字符串长度
          unpadding := int(origData[length-1])
          //截取切片，删除填充字节，并且返回明文
          return origData[:(length - unpadding)], nil
      }
  }

  //实现加密
  func AesEcrypt(origData []byte, key []byte) ([]byte, error) {
      //创建加密算法实例
      block, err := aes.NewCipher(key)
      if err != nil {
          return nil, err
      }
      //获取块的大小
      blockSize := block.BlockSize()
      //对数据进行填充，让数据长度满足需求
      origData = PKCS7Padding(origData, blockSize)
      //采用AES加密方法中CBC加密模式
      blocMode := cipher.NewCBCEncrypter(block, key[:blockSize])
      crypted := make([]byte, len(origData))
      //执行加密
      blocMode.CryptBlocks(crypted, origData)
      return crypted, nil
  }

  //实现解密
  func AesDeCrypt(cypted []byte, key []byte) ([]byte, error) {
      //创建加密算法实例
      block, err := aes.NewCipher(key)
      if err != nil {
          return nil, err
      }
      //获取块大小
      blockSize := block.BlockSize()
      //创建加密客户端实例
      blockMode := cipher.NewCBCDecrypter(block, key[:blockSize])
      origData := make([]byte, len(cypted))
      //这个函数也可以用来解密
      blockMode.CryptBlocks(origData, cypted)
      //去除填充字符串
      origData, err = PKCS7UnPadding(origData)
      if err != nil {
          return nil, err
      }
      return origData, err
  }

  //加密base64
  func EnPwdCode(pwd []byte) (string, error) {
      result, err := AesEcrypt(pwd, getKey())
      if err != nil {
          return "", err
      }
      return base64.StdEncoding.EncodeToString(result), err
  }

  //解密
  func DePwdCode(pwd string) ([]byte, error) {
      //解密base64字符串
      pwdByte, err := base64.StdEncoding.DecodeString(pwd)
      if err != nil || len(pwdByte) <= 0 {
          return nil, err
      }
      //执行AES解密
      return AesDeCrypt(pwdByte, getKey())
  }

  //加密base64
  func EnPwdUserCode(pwd []byte) (string, error) {
      result, err := AesEcrypt(pwd, getUserKey())
      if err != nil {
          return "", err
      }
      return base64.StdEncoding.EncodeToString(result), err
  }

  //解密
  func DePwdUserCode(pwd string) ([]byte, error) {
      //解密base64字符串
      pwdByte, err := base64.StdEncoding.DecodeString(pwd)
      if err != nil || len(pwdByte) <= 0 {
          return nil, err
      }
      //执行AES解密
      return AesDeCrypt(pwdByte, getUserKey())
  }