用C# 实现标准MD5WithRSA算法

   看到网上 很多用C#  实现MD5WithRSA算法，都是使用的 证书，通过加载证书 和证书密码加密。

  但是实际中，我们也有通过 密钥加密的情况，如是找了很久 终于找到方法，首先要下载一个 BouncyCastle.Crypto.dll 。

   话不多说，贴代码：

   

  public class md5withRsa
    {
        public static Encoding encoding = Encoding.GetEncoding("GBK");
        public static string SignerSymbol = "MD5withRSA";

        public  md5withRsa() { }

        public  md5withRsa(Encoding e, string s)
        {
            encoding = e;
            SignerSymbol = s;
        }

        private static AsymmetricKeyParameter CreateKEY(bool isPrivate, string key)
        {
            byte[] keyInfoByte = Convert.FromBase64String(key);

            if (isPrivate)
                return PrivateKeyFactory.CreateKey(keyInfoByte);
            else
                return PublicKeyFactory.CreateKey(keyInfoByte);
        }

        /// <summary>
        /// 数据加密
        /// </summary>
        /// <param name="content">待加密字符串</param>
        /// <param name="privatekey">私钥</param>
        /// <returns>加密后字符串</returns>
        public static string Sign(string content, string privatekey)
        {
            ISigner sig = SignerUtilities.GetSigner(SignerSymbol);

            sig.Init(true, CreateKEY(true, privatekey));

            var bytes = encoding.GetBytes(content);

            sig.BlockUpdate(bytes, 0, bytes.Length);
            byte[] signature = sig.GenerateSignature();
            
            /* Base 64 encode the sig so its 8-bit clean */
            var signedString = Convert.ToBase64String(signature);

            return signedString;
        }

        /// <summary>
        /// 验证签名
        /// </summary>
        /// <param name="content">待签名的字符串</param>
        /// <param name="signData">加密后的文本</param>
        /// <param name="publickey">公钥文本</param>
        /// <returns>是否一致</returns>
        public static bool Verify(string content, string signData, string publickey)
        {
            ISigner signer = SignerUtilities.GetSigner(SignerSymbol);

            signer.Init(false, CreateKEY(false, publickey));

            var expectedSig = Convert.FromBase64String(signData);

            /* Get the bytes to be signed from the string */
            var msgBytes = encoding.GetBytes(content);

            /* Calculate the signature and see if it matches */
            signer.BlockUpdate(msgBytes, 0, msgBytes.Length);
            return signer.VerifySignature(expectedSig);
        }
    }

      这样，我们 通过 Sign()  方法加密，通过Verify()方法验证签名即可。

这里提供一组数据给大家验证：

私钥：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
公钥：MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCTK/DZ0Ve73u2ORRAYrpv07FNHyuTb87xabGMTwEIQV2PhDdAYtiRIO/dAtZ45PUN1N+rtiQQxwIgyKJpYIesFpCbBZ+3YIVf3wlkl9VVSfnUSDWcteN9n0WifBqrKbzJ3gaXi4wXveCMJViqTfgDkfgTV/EC/7h5nwj5VUF6LPQIDAQAB
"中国China"
签名结果：YrzYdPFG0yomJFcM4RbO7WCyrn3LgYpG52f0TVbj1palYwD1y7YI+VJJ+G4xfTvtaXZ7cWCAbTH8j/8WwGUjyJpG5vDkKJzkD8JR1YADaAGMsL43Weeeovj+FjDHt/vLtkJ8cHnJAxAgIilFCENf9X8XlMGbvH2tJ0mYhZat55U=

 还有一个可以在线进行 md5withRsa 加密验签的网站：www.yunsos.com/Md5WithRSA.aspx  可以在线验证。

 希望能够帮到大家！