我遇到AES加密/解密问题。评论的代码有效，但有时会出错“填充无效，无法删除”所以我更改了它，因为它在这里解释Padding is invalid and cannot be removed Exception while decrypting string using "AesManaged" C#
但是当我尝试它时，解密过程中的代码会给出一个空字符串。我不知道哪里弄错了。两个静态函数bytesToString和stringToBytes与加密无关，我在其他地方使用它们。密钥长度和块大小是OKAY。 我在debbuger中找到了这个：
“'csEncrypt.Length'引发了'System.NotSupportedException'类型的异常”
我在3.5 .NET Visual STudio 2008上工作
这里是来自调试器的prtscr，因为你可以看到加密后的块加密为0字节长，而cryptostream有一些例外
如何解决？请给我一些线索。
static class Aes
{
public static string bytesToHexString(byte[] key)
{
return BitConverter.ToString(key).Replace("-", String.Empty);
}
public static byte[] stringToBytes(string key)
{
return Enumerable.Range(0, key.Length)
.Where(x => x % 2 == 0)
.Select(x => Convert.ToByte(key.Substring(x, 2), 16))
.ToArray();
}
public static void generateKeyAndIv(out byte[] key, out byte[] IV)
{
using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
{
aesAlg.BlockSize = 128;
aesAlg.KeySize = 256;
aesAlg.Padding = PaddingMode.None;
//aesAlg.Mode = CipherMode.CBC;
aesAlg.GenerateKey();
aesAlg.GenerateIV();
key = aesAlg.Key;
IV = aesAlg.IV;
}
}
public static string EncryptStringToString(string plainText, byte[] Key, byte[] IV)
{
byte[] bytes =EncryptStringToBytes_Aes(plainText, Key, IV);
return Convert.ToBase64String(bytes);
//return Encoding.UTF8.GetString(bytes, 0, bytes.Length);
}
public static string DecryptStringToString(string cipherText, byte[] Key, byte[] IV)
{
//byte[] bytes = Encoding.UTF8.GetBytes(cipherText);
byte[] bytes = Convert.FromBase64String(cipherText);
return DecryptStringFromBytes_Aes(bytes, Key, IV);
}
public static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key, byte[] IV)
{
// Check arguments.
if (plainText == null || plainText.Length <= 0)
throw new ArgumentNullException("plainText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("Key");
/*byte[] encrypted;
// Create an AesCryptoServiceProvider object
// with the specified key and IV.
using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
{
aesAlg.BlockSize = 128;
aesAlg.KeySize = 256;
aesAlg.Padding = PaddingMode.PKCS7;
aesAlg.Mode = CipherMode.CBC;
aesAlg.Key = Key;
aesAlg.IV = IV;
// Create a decrytor to perform the stream transform.
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for encryption.
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(plainText);
}
}
encrypted = msEncrypt.ToArray();
}
}*/
byte[] encrypted;
// Create an AesManaged object
// with the specified key and IV.
using (AesManaged aesAlg = new AesManaged())
{
// Create a decrytor to perform the stream transform.
aesAlg.Padding = PaddingMode.None;
aesAlg.BlockSize = 128;
aesAlg.KeySize = 256;
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for encryption.
using (var msEncrypt = new MemoryStream())
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
using (var swEncrypt = new StreamWriter(csEncrypt))
{
swEncrypt.Write(plainText);
csEncrypt.FlushFinalBlock();
encrypted = msEncrypt.ToArray();
}
}
//return encrypted;
// Return the encrypted bytes from the memory stream.
return encrypted;
}
public static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV)
{
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
throw new ArgumentNullException("cipherText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("IV");
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
// Create an AesCryptoServiceProvider object
// with the specified key and IV.
using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
{
aesAlg.BlockSize = 128;
aesAlg.KeySize = 256;
aesAlg.Padding = PaddingMode.PKCS7;
aesAlg.Mode = CipherMode.CBC;
aesAlg.Key = Key;
aesAlg.IV = IV;
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for decryption.
using (MemoryStream msDecrypt = new MemoryStream(cipherText))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
// Read the decrypted bytes from the decrypting stream
// and place them in a string.
plaintext = srDecrypt.ReadToEnd();
}
}
}
}
return plaintext;
}
}
好的，也许我会更全面地解释整个情况。我写了自己的安全电子邮件。我有2倍加密。服务器和客户端之间的通信由RSA和AES加密。用户创建的消息也由RSA + AES加密。
发送消息如下：
接收邮件如下：
现在问题在于加密大数据。甚至200-300 kB有时也会出问题。
我发现的另一个有趣的事情是，当我通过调试器运行代码时它可以工作，但是当我运行没有它的代码时。它不起作用。
解决方案
我找到了问题的解决方案。因为我使用不同的密钥/ ivs彼此非常快地使用AES加密/解密两次垃圾收集器没有清理这些对象。解决方案是添加
GC.Collect();
GC.WaitForPendingFinalizers();
在通过DecryptStringFromBytes_Aes和EncryptStringToBytes_Aes返回值之前
我希望它会帮助那些遇到同样问题的人。
答案 0 :(得分：1)
你使用流的方式意味着没有数据写入底层流，我不知道为什么，但我确实找到了一种我已经重做的替代方法。
使用以下代码，您应该能够作为控制台应用程序运行，然后重新整形，以便它适用于您的目的。让我知道它是怎么回事：
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
namespace Encrypto
{
public static class Program
{
public static void Main()
{
const string password = "test";
const string text = "test";
var cipherText = Aes.Encrypt(password, text);
var decrypted = Aes.Decrypt(password, cipherText);
Console.WriteLine(decrypted);
Console.ReadKey();
}
}
internal static class Aes
{
public static EncryptedData Encrypt(string password, string data)
{
return Transform(true, password, data, null) as EncryptedData;
}
public static string Decrypt(string password, EncryptedData data)
{
return Transform(false, password, data.DataString, data.SaltString) as string;
}
private static object Transform(bool encrypt, string password, string data, string saltString)
{
using (var aes = new AesManaged())
{
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
var keyLen = aes.KeySize/8;
var ivLen = aes.BlockSize/8;
const int saltSize = 8;
const int iterations = 8192;
var salt = encrypt ? new byte[saltSize] : Convert.FromBase64String(saltString);
if (encrypt)
{
new RNGCryptoServiceProvider().GetBytes(salt);
}
var bcKey = new Rfc2898DeriveBytes("BLK" + password, salt, iterations).GetBytes(keyLen);
var iv = new Rfc2898DeriveBytes("IV" + password, salt, iterations).GetBytes(ivLen);
var macKey = new Rfc2898DeriveBytes("MAC" + password, salt, iterations).GetBytes(16);
aes.Key = bcKey;
aes.IV = iv;
var rawData = encrypt ? Encoding.UTF8.GetBytes(data) : Convert.FromBase64String(data);
using (var transform = encrypt ? aes.CreateEncryptor() : aes.CreateDecryptor())
using (var memoryStream = encrypt ? new MemoryStream() : new MemoryStream(rawData))
using (var cryptoStream = new CryptoStream(memoryStream, transform, encrypt ? CryptoStreamMode.Write : CryptoStreamMode.Read))
{
if (encrypt)
{
cryptoStream.Write(rawData, 0, rawData.Length);
cryptoStream.FlushFinalBlock();
return new EncryptedData(salt, macKey, memoryStream.ToArray());
}
var originalData = new byte[rawData.Length];
var count = cryptoStream.Read(originalData, 0, originalData.Length);
return Encoding.UTF8.GetString(originalData, 0, count);
}
}
}
public class EncryptedData
{
public EncryptedData(byte[] salt, byte[] mac, byte[] data)
{
Salt = salt;
MAC = mac;
Data = data;
}
private byte[] Salt { get; set; }
public string SaltString
{
get { return Convert.ToBase64String(Salt); }
}
private byte[] MAC { get; set; }
private byte[] Data { get; set; }
public string DataString
{
get { return Convert.ToBase64String(Data); }
}
}
}
}