AES解密给空字符串 [英] Aes decryptor gives empty string
问题描述
我有问题，AES加密/解密。该评论code的工作，但有时也给了错误填充是无效的不能删除，所以我改变了它，因为它是这里<一个解释href="http://stackoverflow.com/questions/10469819/padding-is-invalid-and-cannot-be-removed-exception-while-decrypting-string-using">Padding是无效的，不能删除异常，而使用＆QUOT解密串; AesManaged＆QUOT; C＃
I have problem with AES encryption/decryption. The commented code worked but sometimes gave error "padding is invalid and cannot be removed" so I changed it as it is explained here Padding is invalid and cannot be removed Exception while decrypting string using "AesManaged" C#
但是当我解密过程中尝试了在code下面给出了一个空字符串。我不知道我在哪里出错。这两个静态函数bytesToString和stringToBytes无关加密和我使用它们在其他一些地方。密钥长度和块大小是好的。 我发现这debbuger：
but when I tried it the code below during decryption gives an empty string. I don't know where I make mistake. The two static functions bytesToString and stringToBytes has nothing to do with encryption and I use them in some other place. The key length and block size is OKAY. I found this in debbuger:
csEncrypt.Length'引发了异常类型的System.NotSupportedException'
"'csEncrypt.Length' threw an exception of type 'System.NotSupportedException'"
我工作在.NET 3.5的Visual Studio 2008
I Work on 3.5 .NET Visual STudio 2008
下面是调试器作为美国可以离开块加密后看到prtscr为0字节长的CryptoStream有一些例外
here is prtscr from debugger as u can see after leaving block encrypted is 0 byte long and cryptostream has some exceptions
如何解决？请给我一些线索。
How to fix it? Please give me some clues.
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;
}
}
好吧，也许我会解释整个情况多一点。我写我自己安全的电子邮件。我有2个加密。服务器和客户端之间的通信是通过RSA和AES加密。同时用户创建的消息由RSA + AES加密。
OK, maybe I will explain the whole situation a bit more. I wrote my own secure e-mail. I have 2x encryption. The communication between server and client is encrypted by RSA and AES. Also messages created by users are encrypted by RSA + AES.
发送的消息是这样的：
- 客户端连接到服务器。
- 在他们建立安全连接（服务器发送其公钥，客户端生成通过服务器的公共密钥的AES密钥进行加密，并将其发送给服务器。该服务器和客户端后使用AES密钥进行通信）。
- 在客户端创建XML消息，消息可以包含读为base64这之后，他们用AES进行加密的文件。
- 在该消息被写入到数据库。
recieving消息是这样的：
recieving message look like:
- 连接到服务器。
- 在建立安全连接。
- 从服务器获取信息。
- 在使用RSA私钥解密AES密钥。
- 在使用解密的AES密钥解密消息。
- 如果有文件，然后使用AES和base64_de code它们解密他们字节和保存。
现在的问题是，随着大数据加密。即使200-300 KB有时问题。
Now the problem is with encryption of large data. Even 200-300 kB is sometimes problem.
另一个有趣的事情，我发现的是，当我通过调试运行code它的工作原理，但是当我运行code离不开它。这是行不通的。
Another interesting thing I've discovered is that when I run the code via debugger it works but when I run code without it. It doesn't work.
解决方案
我找到了问题的解决方案。因为我以后彼此不同的密钥/ IVS垃圾收集器使用AES加密/解密两次非常快没清理这些对象。该溶液中加入
I found the solution of problem. Because I used AES encryption/decryption twice very fast after each other with different keys/ivs Garbage Collector didn't clean these objects. The solution was adding
GC.Collect();
GC.WaitForPendingFinalizers();
刚刚返回值由DecryptStringFromBytes_Aes和EncryptStringToBytes_Aes之前
just before returning value by DecryptStringFromBytes_Aes and EncryptStringToBytes_Aes
我希望这会帮助别人谁是有同样的问题，像我了。
I hope that it will help someone who is having same issue like I had.
推荐答案
您正在使用的流意味着没有数据被写入到底层数据流的方式，我不知道为什么，但我没有找到一个替代的办法，我已经返工。
The way you were using the streams meant that there was no data being written to the underlying streams, I do not know why but I did find an alternative approach that I have reworked.
通过以下code，你应该能够作为一个控制台应用程序运行，然后重新塑造它，所以它适用于您的目的。让我知道如何去：
With the following code you should be able to run as a console application and then reshape it so it works for your purposes. Let me know how it goes:
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); }
}
}
}
}
，用于提供这样的回答：<一href="http://stackoverflow.com/questions/4545387/using-aes-encryption-in-net-cryptographicexception-saying-the-padding-is-inva">Using AES加密在.NET - CryptographicException称填充是无效的不能删除
这篇关于AES解密给空字符串的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
