使用BouncyCastle解密Rijndael 256块大小 [英] Decrypt Rijndael 256 Block Size with BouncyCastle
问题描述
我们有一个用于进行加密的帮助程序类，如果老实说，它可能是几年前从Stack Overflow复制而来的。
We have a helper class for doing encryption that, if I'm going to be honest, was probably copied from Stack Overflow years ago.
当前，我们正在尝试将某些代码移植到.NET Core，但由于使用<$的.NET Core实现，我们发现它不起作用。 c $ c> RijndaelManaged 不支持256块大小。从我阅读的内容来看，BouncyCastle似乎仍然应该支持它，但我无法使其正常工作。 未加密的文本只是一堆乱码。我确定我做错了什么，但是对于我自己的一生，我无法弄清楚。
Currently we're trying to port some of this code to .NET Core and we're finding that it doesn't work because the .NET Core implementation of RijndaelManaged doesn't support a 256 blocksize. From what I've read, it seems like BouncyCastle should still support it, but I can't get it to work. The "unencrypted" text is just a bunch of gibberish. I'm sure I'm doing something wrong, but for the life of me I can't figure this out.
这是该类的原始.Net Framework版本：
Here's the original .Net Framework version of the class:
internal static class StringEncryptor
{
private const int Keysize = 256;
private const int _iterations = 1000;
private const int _hashLenth = 20;
public static string Encrypt(string plainText, string superSecretPassPhrase)
{
// Salt and IV is randomly generated each time, but is preprended to encrypted cipher text
// so that the same Salt and IV values can be used when decrypting.
var saltStringBytes = Generate256BitsOfRandomEntropy();
var ivStringBytes = Generate256BitsOfRandomEntropy();
var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
using (var password = new Rfc2898DeriveBytes(superSecretPassPhrase, saltStringBytes, _iterations))
{
var keyBytes = password.GetBytes(Keysize / 8);
using (var symmetricKey = new RijndaelManaged())
{
symmetricKey.BlockSize = 256;
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
{
using (var memoryStream = new MemoryStream())
{
using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
{
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
// Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
var cipherTextBytes = saltStringBytes;
cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
memoryStream.Close();
cryptoStream.Close();
return WebEncoders.Base64UrlEncode(cipherTextBytes);
//return System.Web.HttpServerUtility.UrlTokenEncode(cipherTextBytes);
}
}
}
}
}
}
public static string Decrypt(string cipherText, string superSecretPassPhrase)
{
if (cipherText == null)
{
throw new ArgumentNullException(nameof(cipherText));
}
// Get the complete stream of bytes that represent:
// [32 bytes of Salt] + [32 bytes of IV] + [n bytes of CipherText]
var cipherTextBytesWithSaltAndIv = WebEncoders.Base64UrlDecode(cipherText);
// Get the saltbytes by extracting the first 32 bytes from the supplied cipherText bytes.
var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
// Get the IV bytes by extracting the next 32 bytes from the supplied cipherText bytes.
var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
// Get the actual cipher text bytes by removing the first 64 bytes from the cipherText string.
var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();
using (var password = new Rfc2898DeriveBytes(superSecretPassPhrase, saltStringBytes, _iterations))
{
var keyBytes = password.GetBytes(Keysize / 8);
using (var symmetricKey = new RijndaelManaged())
{
symmetricKey.BlockSize = 256;
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
{
using (var memoryStream = new MemoryStream(cipherTextBytes))
{
using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
{
var plainTextBytes = new byte[cipherTextBytes.Length];
var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
}
}
}
}
}
}
private static byte[] Generate256BitsOfRandomEntropy()
{
var randomBytes = new byte[32]; // 32 Bytes will give us 256 bits.
using (var rngCsp = new RNGCryptoServiceProvider())
{
// Fill the array with cryptographically secure random bytes.
rngCsp.GetBytes(randomBytes);
}
return randomBytes;
}
}
这是我尝试使Decrypt方法起作用的尝试与BouncyCastle：
And here is my attempt to get the Decrypt method working with BouncyCastle:
/// <summary>
/// Decrypt a string
/// </summary>
/// <param name="cipherText"></param>
/// <returns></returns>
public static string Decrypt(string cipherText)
{
if (cipherText == null)
{
throw new ArgumentNullException(nameof(cipherText));
}
// Get the complete stream of bytes that represent:
// [32 bytes of Salt] + [32 bytes of IV] + [n bytes of CipherText]
var cipherTextBytesWithSaltAndIv = WebEncoders.Base64UrlDecode(cipherText);
// Get the saltbytes by extracting the first 32 bytes from the supplied cipherText bytes.
var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
// Get the IV bytes by extracting the next 32 bytes from the supplied cipherText bytes.
var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
// Get the actual cipher text bytes by removing the first 64 bytes from the cipherText string.
var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();
using (var password = new Rfc2898DeriveBytes(superSecretPassPhrase, saltStringBytes, _iterations))
{
var keyBytes = password.GetBytes(Keysize / 8);
var engine = new RijndaelEngine(256);
var blockCipher = new CbcBlockCipher(engine);
var cipher = new PaddedBufferedBlockCipher(blockCipher, new Pkcs7Padding());
var keyParam = new KeyParameter(keyBytes);
var keyParamWithIV = new ParametersWithIV(keyParam, ivStringBytes, 0, 32);
cipher.Init(true, keyParamWithIV);
var outputBytes = new byte[cipher.GetOutputSize(cipherTextBytes.Length)];
var length = cipher.ProcessBytes(cipherTextBytes, outputBytes, 0);
var finalBytes = cipher.DoFinal(outputBytes, 0, length);
var final = Encoding.UTF8.GetString(finalBytes);
return final;
}
}
}
谢谢！我确定我在做一些愚蠢的事情，但是我不是密码专家，并且在查找良好的BouncyCastle示例方面遇到了麻烦。
Thanks in advance! I'm sure I'm doing something dumb, but I'm not a cryptographic expert, and I'm having trouble finding good BouncyCastle examples.
推荐答案
我相信您的问题就在这行
I believe your problem is in the line
cipher.Init（true，keyParamWithIV）;
cipher.Init(true, keyParamWithIV);
第一个参数初始化密码，如果为true，则加密，如果为false，则解密。如果将其设置为false，它应该可以工作。
the first parameter initializes the cipher for encryption if true and for decryption if false. If you set it to false it should work.
这篇关于使用BouncyCastle解密Rijndael 256块大小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！
