Question

我有一个AES Cryptography包装器和单元测试，已经工作了一年多。现在安装VS 2012（或者可能是对.net Framework 4的更新）后，单元测试没有通过。当我传入一个错误的传递但没有抛出ArgumentNullException时，streamreader块抛出了CryptographicException。

代码到了。 https://github.com/jnaus/Cryptography

这是现在不起作用的单元测试。（BadSaltTest有同样的问题）

[TestMethod]
[ExpectedException(typeof(CryptographicException),
  "Bad password was inappropriately allowed")]
public void BadPasswordTest()
{
    var cipherText = EncryptString();
    var decryptedText = AESCryptography.DecryptStringAES
        (cipherText,"A bad password", salt);
}

测试结果：测试方法CryptographyTest.AESTest.BadPasswordTest引发异常System.ArgumentNullException，但预期会出现异常System.Security.Cryptography.CryptographicException。异常消息：System.ArgumentNullException：值不能为null。参数名称：inputBuffer

解密代码。

public static string DecryptStringAES(string cipherText, 
    string password, byte[] salt)
{   
    RijndaelManaged aesAlg = null;
    string plaintext = null;

    try 
    {
        // generate the key from the shared secret and the salt
        Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(password, salt);

        // Create a RijndaelManaged object
        // with the specified key and IV.
        aesAlg = new RijndaelManaged();
        aesAlg.Key = key.GetBytes(aesAlg.KeySize/8);
        aesAlg.IV = key.GetBytes(aesAlg.BlockSize/8);

        // Create a decrytor to perform the stream transform.
        ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, 
            aesAlg.IV);
        // Create the streams used for decryption.                
        byte[] bytes = Convert.FromBase64String(cipherText);

        using (MemoryStream msDecrypt = new MemoryStream(bytes)) 
        {
            using (CryptoStream csDecrypt = 
                new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)) 
            {
                //StreamReader now gives ArgumentNullException
                using (StreamReader srDecrypt = new StreamReader(csDecrypt)) 
                {
                    // Read the decrypted bytes from the decrypting stream
                    // and place them in a string.
                    plaintext = srDecrypt.ReadToEnd();
                }
            }
        }
    }
    finally 
    {
        // Clear the RijndaelManaged object.
        if (aesAlg != null)
        {
            aesAlg.Clear();
        }
    }
    return plaintext;
}

Answer 1

在搜索了一下之后，这确实看起来确实是微软所诟病的一个错误（见Microsoft Connect）。个人不是建议的解决方法的忠实粉丝，因为它确实不应该需要，但它会在我想的同时做。

Answer 2

您上面发布的代码为我工作（我必须编写一些代码来创建要传递的加密字符串）。使用.Net Framework 4在VS2012中编译并运行。

我使用的加密代码是：

    private static string EncryptStringAES(string plainText, string password, byte[] salt)
    {
        RijndaelManaged aesAlg = null;
        string cypherText = null;

        try
        {
            // generate the key from the shared secret and the salt
            Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(password, salt);

            // Create a RijndaelManaged object
            // with the specified key and IV.
            aesAlg = new RijndaelManaged();
            aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
            aesAlg.IV = key.GetBytes(aesAlg.BlockSize / 8);

            // Create an encryptor to perform the stream transform.
            ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
            // Create the streams used for encryption.                
            byte[] bytes = new UTF8Encoding().GetBytes(plainText);

            using (MemoryStream msEncrypt = new MemoryStream())
            {
                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                {
                    csEncrypt.Write(bytes, 0, bytes.Length);
                    csEncrypt.FlushFinalBlock();
                    cypherText = Convert.ToBase64String(msEncrypt.ToArray());
                }
            }
        }
        finally
        {
            // Clear the RijndaelManaged object.
            if (aesAlg != null)
            {
                aesAlg.Clear();
            }
        }
        return cypherText;
    }

使用以下方法进行方法调用：

        byte[] salt =  new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
        string test = DecryptStringAES(EncryptStringAES("This is a test", "Test", salt), "Test", salt);

结果字符串（测试）包含“这是一个测试”。

AES解密异常更改

2 个答案: