c# - 在 C# 中使用 Bouncy CaSTLe 加密/解密

Question

我正在使用“BouncyCaSTLe.Crypto.dll”在我的应用程序中加密/解密字符串。我正在使用以下 code from this blog :

1. 我有一个类 BCEngine，与上面提到的链接中给出的完全相同。

   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);
          }
      }
   }
   

我使用的是 asp.net 表单，我在其中编写了如下代码:

    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);
      }
    }

不确定，但由于某些原因，我在调用 btnEncrypt_Click 时遇到异常

“ key 长度不是 128/192/256 位。”

有人可以指导吗？我是一个完整的新手。提前致谢。

Answer 1

您的 string key = "DFGFRT"; 不是 128/192/256 位。

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

要获得 128 位 key ，您需要一个 16 字节的字符串，所以为了安全起见，我会使用 16 个字符的字符串，因此如果使用单字节字符，它将是一个 128 位 key ，如果使用宽字符，它将是 256 .