4

我有一些文本，由 C# 的 AesManaged 加密，必须在 WinRT Metro 应用程序中解密。我无法更改加密代码，因为该代码具有其他无法更改的依赖项。

加密函数如下所示：

// Note: Edited out possibly real password and salt:
Guid password = Guid.Parse("AAAAAAAAA-AAAA-AAAA-AAAA-AAAAAAAAAAAA");
Guid salt = Guid.Parse("AAAAAAAAA-BBBB-BBBB-BBBB-AAAAAAAAAAAA");

string EncryptedValue(string data)
{   
byte[] passwordBytes = password.ToByteArray();
byte[] saltBytes = salt.ToByteArray();

byte[] bKey = new byte[16];
for(int i = 0; i < 16; i++)
{
    bKey[i] = passwordBytes[i];
}

string encryptedData = String.Empty;
using (System.Security.Cryptography.AesManaged aesAlg = new System.Security.Cryptography.AesManaged())
{
    aesAlg.Key = bKey;
    aesAlg.IV = saltBytes;

    // Create a decrytor to perform the stream transform.
    System.Security.Cryptography.ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

    // Create the streams used for encryption.
    using (MemoryStream msEncrypt = new MemoryStream())
    {
        using (System.Security.Cryptography.CryptoStream csEncrypt = new System.Security.Cryptography.CryptoStream(msEncrypt, encryptor, System.Security.Cryptography.CryptoStreamMode.Write))
        {
            using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
            {

                //Write all data to the stream.
                swEncrypt.Write(data);
            }

            encryptedData = Convert.ToBase64String(msEncrypt.ToArray());
        }
    }
}

return encryptedData;
}

示例数据：

   // Decrypted value is: 2029
   var _id = EncryptedSettingsBase.Decrypt("ROSNJ1XnAozF7LC0wW8AOg==");

我阅读了以下帖子： http ://social.msdn.microsoft.com/Forums/en-US/winappswithcsharp/thread/7cfcc576-1c2c-4a50-a546-09a45d3ff41f 这看起来像同样的问题，但是我没有能够让他们的建议发挥作用，因为我得到了例外：'数据错误（循环冗余检查）。（来自 HRESULT 的异常：0x80070017）'。

internal class EncryptedSettingsBase
{
    public static string Decrypt(string cipherText)
    {
        var passwordBytes = (new Guid("AAAAAAAAA-AAAA-AAAA-AAAA-AAAAAAAAAAAA")).ToByteArray();
        var salt = (new Guid("AAAAAAAAA-BBBB-AAAA-AAAA-AAAAAAAAAAAA")).ToString();

        byte[] bKey = new byte[16];
        for (int i = 0; i < 16; i++)
        {
            bKey[i] = passwordBytes[i];
        }

        IBuffer pwBuffer = CryptographicBuffer.CreateFromByteArray(bKey);
        IBuffer saltBuffer = CryptographicBuffer.ConvertStringToBinary(salt, BinaryStringEncoding.Utf16LE);
        IBuffer cipherBuffer = CryptographicBuffer.DecodeFromBase64String(cipherText);

        // Derive key material for password size 32 bytes for AES256 algorithm
        KeyDerivationAlgorithmProvider keyDerivationProvider = KeyDerivationAlgorithmProvider.OpenAlgorithm("PBKDF2_SHA1");
        // using salt and 1000 iterations
        KeyDerivationParameters pbkdf2Parms = KeyDerivationParameters.BuildForPbkdf2(saltBuffer, 1000);

        // create a key based on original key and derivation parmaters
        CryptographicKey keyOriginal = keyDerivationProvider.CreateKey(pwBuffer);
        IBuffer keyMaterial = CryptographicEngine.DeriveKeyMaterial(keyOriginal, pbkdf2Parms, 32);
        CryptographicKey derivedPwKey = keyDerivationProvider.CreateKey(pwBuffer);

        // derive buffer to be used for encryption salt from derived password key 
        IBuffer saltMaterial = CryptographicEngine.DeriveKeyMaterial(derivedPwKey, pbkdf2Parms, 16);

        // display the keys - because KeyDerivationProvider always gets cleared after each use, they are very similar unforunately
        string keyMaterialString = CryptographicBuffer.EncodeToBase64String(keyMaterial);
        string saltMaterialString = CryptographicBuffer.EncodeToBase64String(saltMaterial);

        SymmetricKeyAlgorithmProvider symProvider = SymmetricKeyAlgorithmProvider.OpenAlgorithm("AES_CBC_PKCS7");
        // create symmetric key from derived password material
        CryptographicKey symmKey = symProvider.CreateSymmetricKey(keyMaterial);

        // encrypt data buffer using symmetric key and derived salt material
        IBuffer resultBuffer = CryptographicEngine.Decrypt(symmKey, cipherBuffer, saltMaterial);
        string result = CryptographicBuffer.ConvertBinaryToString(BinaryStringEncoding.Utf16LE, resultBuffer);
        return result;
    }
}

我可能在做一些愚蠢的事情，但我并不完全理解这些东西。有人知道我要去哪里错了吗？

任何帮助深表感谢。

干杯，乔恩

4

2 回答 2

3

您在一侧使用 PBKDF2，而在 .net 部分中没有使用 PBKDF2。不幸的是，您无法更改的部分没有正确使用密钥；它只是直接使用 UID。

于 2012-08-01T18:49:35.970 回答
3

如果我可以更改所有依赖项以正确加密，则以下代码可以解决问题：

这里的代码有帮助：http: //visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/2966549-make-equal-aesmanaged-snippet-as-in-silverlight-an

加密代码，C# 4.0 端：

string salt = "AAAAAAAAA-AAAA-AAAA-AAAA-AAAAAAAAAAAA";
string password = "AAAAAAAAA-BBBB-AAAA-AAAA-AAAAAAAAAAAA";

string EncryptedValue(string data)
{   
byte[] saltBytes = System.Text.Encoding.UTF8.GetBytes(salt);

string encryptedData = String.Empty;
using (System.Security.Cryptography.AesManaged aes = new System.Security.Cryptography.AesManaged())
{
    var rfc = new System.Security.Cryptography.Rfc2898DeriveBytes(password, saltBytes);

    aes.BlockSize = aes.LegalBlockSizes[0].MaxSize; 
    aes.KeySize = aes.LegalKeySizes[0].MaxSize; 
    aes.Key = rfc.GetBytes(32); 
    rfc.Reset(); 
    aes.IV = rfc.GetBytes(16);

    // Create a decrytor to perform the stream transform.
    System.Security.Cryptography.ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);

    // Create the streams used for encryption.
    using (MemoryStream msEncrypt = new MemoryStream())
    {
        using (System.Security.Cryptography.CryptoStream csEncrypt = new System.Security.Cryptography.CryptoStream(msEncrypt, encryptor, System.Security.Cryptography.CryptoStreamMode.Write))
        {
            using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
            {
                // Write all data to the stream.
                swEncrypt.Write(data);
            }

            encryptedData = Convert.ToBase64String(msEncrypt.ToArray());
        }
    }
}

return encryptedData;
}

WinRT端解密代码：

protected string Decrypt(string encryptedData)
    {
        const string password = "AAAAAAAAA-AAAA-AAAA-AAAA-AAAAAAAAAAAA";
        const string salt = "AAAAAAAAA-BBBB-AAAA-AAAA-AAAAAAAAAAAA";

        IBuffer pwBuffer = CryptographicBuffer.ConvertStringToBinary(password, BinaryStringEncoding.Utf8);
        IBuffer saltBuffer = CryptographicBuffer.ConvertStringToBinary(salt, BinaryStringEncoding.Utf8);
        IBuffer cipherBuffer = CryptographicBuffer.DecodeFromBase64String(encryptedData);

        KeyDerivationAlgorithmProvider keyDerivationProvider = KeyDerivationAlgorithmProvider.OpenAlgorithm("PBKDF2_SHA1");

        KeyDerivationParameters pbkdf2Parms = KeyDerivationParameters.BuildForPbkdf2(saltBuffer, 1000);

        CryptographicKey keyOriginal = keyDerivationProvider.CreateKey(pwBuffer);
        IBuffer keyMaterial = CryptographicEngine.DeriveKeyMaterial(keyOriginal, pbkdf2Parms, 32);

        CryptographicKey derivedPwKey = keyDerivationProvider.CreateKey(pwBuffer);

        IBuffer saltMaterial = CryptographicEngine.DeriveKeyMaterial(derivedPwKey, pbkdf2Parms, 16);

        SymmetricKeyAlgorithmProvider symProvider = SymmetricKeyAlgorithmProvider.OpenAlgorithm("AES_CBC_PKCS7");

        CryptographicKey symmKey = symProvider.CreateSymmetricKey(keyMaterial);

        IBuffer resultBuffer = CryptographicEngine.Decrypt(symmKey, cipherBuffer, saltMaterial);

        byte[] asd;
        CryptographicBuffer.CopyToByteArray(resultBuffer, out asd);
        string result = CryptographicBuffer.ConvertBinaryToString(BinaryStringEncoding.Utf8, resultBuffer);
        return result;
    }
于 2012-08-02T08:39:34.787 回答