使用AesManaged“填充无效，无法移除”
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总是出现异常。这里的字符串得到了正确的加密和解密，然后在Console.WriteLine打印正确的字符串后，我得到了CryptographicException“填充是无效的，无法被删除”。
有什么想法吗？
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);
}
}回答 6
Stack Overflow用户
发布于 2009-03-02 23:16:00
诀窍是使用MemoryStream.ToArray()。我还更改了您的代码，使其在加密和解密时都使用CryptoStream编写。而且您不需要显式地调用CryptoStream.FlushFinalBlock()，因为您在using()语句中拥有它，并且刷新将在Dispose()上发生。下面的方法对我很有效。
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);
}此外，我猜您知道您需要显式设置AesManaged实例的Mode，并使用System.Security.Cryptography.Rfc2898DeriveBytes从密码和盐派生密钥和IV。
另请参阅：
Stack Overflow用户
发布于 2010-12-01 18:51:13
此异常可能是由多个加密参数中的任何一个不匹配引起的。
我使用Security.Cryptography.Debug接口跟踪加密/解密方法中使用的所有参数。
最后，我发现我的问题是我在设置Key之后设置了KeySize属性，导致类重新生成一个随机密钥，而不是使用我最初设置的密钥。
Stack Overflow用户
发布于 2019-06-12 09:39:50
为了它的价值，我会记录下我所面对的。在CryptoStream关闭之前，我正在尝试读取加密器内存流。我太天真了，我浪费了一天的时间调试它。
public static byte[] Encrypt(byte[] buffer, byte[] sessionKey, out byte[] iv)
{
byte[] encrypted;
iv = null;
using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider { Mode = CipherMode.CBC, Padding = PaddingMode.PKCS7 })
{
aesAlg.Key = sessionKey;
iv = aesAlg.IV;
ICryptoTransform encryptor = aesAlg.CreateEncryptor(sessionKey, iv);
// Create the streams used for encryption.
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
csEncrypt.Write(buffer, 0, buffer.Length);
//This was not closing the cryptostream and only worked if I called FlushFinalBlock()
//encrypted = msEncrypt.ToArray();
}
encrypted = msEncrypt.ToArray();
return encrypted;
}
}
}在cypto流关闭后移动读取的加密器内存流解决了这个问题。正如Cheeso提到的。如果使用using块，则不需要调用FlushFinalBlock()。
https://stackoverflow.com/questions/604210
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