加密/解密在C＃中使用充气城堡 [英] Encrypt/Decrypt using Bouncy Castle in C#

问题描述

我使用的是BouncyCastle.Crypto.dll的加密/解密的字符串。我现在用的是
以下的从这个博客代码：

I am using the "BouncyCastle.Crypto.dll" for encrypt/decrypt a string in my app. I am using the following code from this blog:

1. 我有一个类BCEngine，完全一样，在上述给出的链接之一。

1. I have a class BCEngine, exactly the same as the one given in the link mentioned above.

public class BCEngine
{
   private readonly Encoding _encoding;
   private readonly IBlockCipher _blockCipher;
   private PaddedBufferedBlockCipher _cipher;
   private IBlockCipherPadding _padding;

   public BCEngine(IBlockCipher blockCipher, Encoding encoding)
   {
      _blockCipher = blockCipher;
      _encoding = encoding;
   }

   public void SetPadding(IBlockCipherPadding padding)
   {
       if (padding != null)
         _padding = padding;
   }

   public string Encrypt(string plain, string key)
   {
       byte[] result = BouncyCastleCrypto(true, _encoding.GetBytes(plain), key);
       return Convert.ToBase64String(result);
   }

   public string Decrypt(string cipher, string key)
   {
      byte[] result = BouncyCastleCrypto(false, Convert.FromBase64String(cipher), key);
      return _encoding.GetString(result);
   }

/// <summary>
///
/// </summary>
/// <param name="forEncrypt"></param>
/// <param name="input"></param>
/// <param name="key"></param>
/// <returns></returns>
/// <exception cref="CryptoException"></exception>
private byte[] BouncyCastleCrypto(bool forEncrypt, byte[] input, string key)
{
    try
    {
        _cipher = _padding == null ? new PaddedBufferedBlockCipher(_blockCipher) : new PaddedBufferedBlockCipher(_blockCipher, _padding);
        byte[] keyByte = _encoding.GetBytes(key);
        _cipher.Init(forEncrypt, new KeyParameter(keyByte));
        return _cipher.DoFinal(input);
    }
    catch (Org.BouncyCastle.Crypto.CryptoException ex)
    {
        throw new CryptoException(ex.Message);
    }
}

}

}

我使用其中下面给出我写的代码一个asp.net的形式：

I am using an asp.net form in which i have written code as given below:

    public partial class EncryptionForm : System.Web.UI.Page
    {
      Encoding _encoding;
      IBlockCipherPadding _padding;
      string key = "DFGFRT";
       string textToBeEncrypted = "Original text. Please encrypt me.";
       string txtEncryptedText = string.empty;
       string txtDecryptedText = string.empty;

      protected void Page_Load(object sender, EventArgs e)
      {
          _encoding = Encoding.ASCII; 
          Pkcs7Padding pkcs = new Pkcs7Padding();
          _padding = pkcs;   
      }

      protected void btnEncrypt_Click(object sender, EventArgs e)
      {
          txtEncryptedText = AESEncryption(textToBeEncrypted, key, true);
      }

      protected void btnDecrypt_Click(object sender, EventArgs e)
      {
          txtDecryptedText = AESDecryption(txtEncryptedText.Text, key, true);
      }

      public string AESEncryption(string plain, string key, bool fips)
      {
          BCEngine bcEngine = new BCEngine(new AesEngine(), _encoding);
          bcEngine.SetPadding(_padding);
          return bcEngine.Encrypt(plain, key);
      }

      public string AESDecryption(string cipher, string key, bool fips)
      {
          BCEngine bcEngine = new BCEngine(new AesEngine(), _encoding);
          bcEngine.SetPadding(_padding);
          return bcEngine.Decrypt(cipher, key);
      }
    }

不知道，但由于某些原因，我得到一个例外，当我打电话btnEncrypt_Click

Not sure, but due to some reason, I get an exception when I call the btnEncrypt_Click

密钥长度不128/192/256位。

"Key length not 128/192/256 bits."

灿有人请指导？我是一个完整的新手到这一点。
在此先感谢

Can anybody please guide? I am a complete newbie to this. Thanks in Advance.

推荐答案

您字符串键=DFGFRT; 不是128/192/256位。

Your string key = "DFGFRT"; is not 128/192/256 bits.

DFGFRT 是6个字符，这是6（或12？）字节= 8 * 12 = 96位（最多）。

DFGFRT is 6 characters, which is 6 (or 12?) bytes = 8*12 = 96 bits (at most).

要得到你需要一个16字节的字符串，一个128位的密钥，所以我会去在安全方面，并使用16字符串，所以这将是一个128位如果钥匙如果使用的宽字符使用单字节字符和256。

To get a 128 bit key you need a 16 byte string, so I'd go on the safe side and use a 16 character string so it will be a 128 bit key if using single byte characters and 256 if using wide characters.

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