code: func aesDecrypt(cryptStr []byte, mode cipher.BlockMode) ([]byte, error) {
  	blockSize := mode.BlockSize()
  	if len(cryptStr)%blockSize != 0 {
  		return nil, errors.New("Corrupted data")
  	}
  	data := make([]byte, len(cryptStr))
  	mode.CryptBlocks(data, cryptStr)
  	plain, err := PKCS7Unpad(data, blockSize)
  	if err != nil {
  		return nil, err
  	}
  	return plain, nil
  }
docs: // aesDecrypt decrypts data using AES.