Question

我正在使用“BouncyCastle.Crypto.dll”来加密/解密我的应用中的字符串。我正在使用关注code from this blog：

我有一个BCEngine类，与上面提到的链接完全相同。

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，其中我编写了如下代码：

    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，但由于某种原因，我在调用btnEncrypt_Click时遇到异常

“密钥长度不是128/192/256位。”

有人可以指导吗？我是一个完整的新手。在此先感谢。

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）。

要获得一个128位密钥，你需要一个16字节的字符串，所以我会安全地使用16个字符的字符串，因此如果使用单字节字符则为128位密钥，如果使用宽字符则为256

Answer 2

相当简单，你的密钥是“DFGFRT”，它是6个字符/字节，即6 * 8 = 48位。

使用的加密方法需要长度为128/192/256位的密钥，相当于16/24/32个字符/字节。

使用C＃中的Bouncy Castle加密/解密

2 个答案: