通用Windows平台（UWP）中的加密/解密存在数据错误（循环冗余校验）

Posted 2021-03-28

我在我的通用Windows平台（UWP）应用程序中使用DES加密/解密算法。数据加密工作正常，但解密有错误：

这是我的代码：

private static byte[] IV = { 12, 11, 12, 55, 0, 108, 121, 54 };
private static string stringKey = "SA/DF@#asx.";
private static BinaryStringEncoding encoding;
private static byte[] keyByte;
private static SymmetricKeyAlgorithmProvider objAlg;
private static CryptographicKey Key;

加密：

public static string Encrypt(String strMsg)
{
     IBuffer buffMsg = CryptographicBuffer.ConvertStringToBinary(strMsg,encoding);
     IBuffer buffEncrypt = CryptographicEngine.Encrypt(Key, buffMsg, IV.AsBuffer());
     return CryptographicBuffer.EncodeToBase64String(buffEncrypt);
}

解密：

public static string Decrypt(String strMsg)
{
     var bb = CryptographicBuffer.ConvertStringToBinary(strMsg, encoding);
     IBuffer buffEncrypt = CryptographicEngine.Decrypt(Key, bb, IV.AsBuffer());
     return CryptographicBuffer.EncodeToBase64String(buffEncrypt);
}

并且解密有这个错误：

Data error (cyclic redundancy check). (Exception from HRESULT: 0x80070017)

怎么了？

答案

只是查看代码，似乎您将加密结果（通常是二进制blob转换为Base64字符串，这很好）。但是，当您解密时，您并没有完全撤消Base64编码，而是将其视为二进制blob，难怪解码将失败。

另一答案

好的，我终于找到了答案：找到解密步骤时出错了！

正确的算法：

private static byte[] IV = { 12, 11, 12, 55, 0, 108, 121, 54 };
private static string stringKey = "SA/DF@#asx.";
private static BinaryStringEncoding encoding;
private static byte[] keyByte;
private static SymmetricKeyAlgorithmProvider objAlg;
private static CryptographicKey Key;

UWP中的DES加密：

public static string Encrypt(String strMsg)
{
     IBuffer buffMsg = CryptographicBuffer.ConvertStringToBinary(strMsg,encoding);
     IBuffer buffEncrypt = CryptographicEngine.Encrypt(Key, buffMsg, IV.AsBuffer());
     return CryptographicBuffer.EncodeToBase64String(buffEncrypt);
}

和解密步骤：

public static string Decrypt(String strMsg)
{
    Byte[] bb = Convert.FromBase64String(strMsg);
    IBuffer buffEncrypt = CryptographicEngine.Decrypt(Key, bb.AsBuffer(), IV.AsBuffer());
    return CryptographicBuffer.ConvertBinaryToString(encoding, buffEncrypt);
}