使用 AesManaged“填充无效且无法删除”

我正在尝试使用 AesManaged 进行简单的加密/解密，但在尝试关闭解密流时不断出现异常。这里的字符串被正确加密和解​​密，然后在 Console.WriteLine 打印正确的字符串后，我收到 CryptographicException“填充无效且无法删除”。

有任何想法吗？

MemoryStream ms = new MemoryStream();
byte[] rawPlaintext = Encoding.Unicode.GetBytes("This is annoying!");

using (Aes aes = new AesManaged())
{
  aes.Padding = PaddingMode.PKCS7;
  aes.Key = new byte[128/8];
  aes.IV = new byte[128/8];

  using (CryptoStream cs = new CryptoStream(ms, aes.CreateEncryptor(),
                                            CryptoStreamMode.Write))
  {
    cs.Write(rawPlaintext, 0, rawPlaintext.Length);
    cs.FlushFinalBlock();
  }

  ms = new MemoryStream(ms.GetBuffer());
  using (CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(),
                                            CryptoStreamMode.Read))
  {
    byte[] rawData = new byte[rawPlaintext.Length];
    int len = cs.Read(rawData, 0, rawPlaintext.Length);
    string s = Encoding.Unicode.GetString(rawData);
    Console.WriteLine(s);
  }
}

诀窍是使用MemoryStream.ToArray()。 我还更改了您的代码，以便它使用CryptoStream写入，加密和解密。而且你不需要打电话CryptoStream.FlushFinalBlock()明确地，因为你把它放在using()声明，并且刷新将发生在Dispose()。以下内容对我有用。

byte[] rawPlaintext = System.Text.Encoding.Unicode.GetBytes("This is all clear now!");

using (Aes aes = new AesManaged())
{
    aes.Padding = PaddingMode.PKCS7;
    aes.KeySize = 128;          // in bits
    aes.Key = new byte[128/8];  // 16 bytes for 128 bit encryption
    aes.IV = new byte[128/8];   // AES needs a 16-byte IV
    // Should set Key and IV here.  Good approach: derive them from 
    // a password via Cryptography.Rfc2898DeriveBytes 
    byte[] cipherText= null;
    byte[] plainText= null;

    using (MemoryStream ms = new MemoryStream())
    {
        using (CryptoStream cs = new CryptoStream(ms, aes.CreateEncryptor(), CryptoStreamMode.Write))
        {
            cs.Write(rawPlaintext, 0, rawPlaintext.Length);
        }

        cipherText= ms.ToArray();
    }


    using (MemoryStream ms = new MemoryStream())
    {
        using (CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Write))
        {
            cs.Write(cipherText, 0, cipherText.Length);
        }

        plainText = ms.ToArray();
    }
    string s = System.Text.Encoding.Unicode.GetString(plainText);
    Console.WriteLine(s);
}

另外，我猜你知道你会想要明确设置Mode http://msdn.microsoft.com/en-us/library/system.security.cryptography.aesmanaged.mode.aspxAesManaged 实例的，并使用系统.安全.加密.Rfc2898DeriveBytes http://msdn.microsoft.com/en-us/library/system.security.cryptography.rfc2898derivebytes.aspx从密码和盐中导出密钥和 IV。

也可以看看：
- Aes管理 http://msdn.microsoft.com/en-us/library/system.security.cryptography.aesmanaged.aspx