分享一个C#的RSA加密解密的实用类

RSA加密解密，本例子是将java代码编写的私钥转换成C#的xml来实现RSA的加密解密操作算法，因为有时对接时，由于公钥和私钥都是java生成的，但是java生成秘钥C#直接是无法使用的，必须需要先通过转换成C#可用xml格式的字符串表示，然后再拿着对应的秘钥去做C#的RSA解密加密操作。

废话不多说，上代码：

 public static string RSAEncryptMore(string xmlPublicKey, string m_strEncryptString)
        {
            if (string.IsNullOrEmpty(m_strEncryptString))
            {
                return string.Empty;
            }

            if (string.IsNullOrEmpty(xmlPublicKey))
            {
                throw new ArgumentException("Invalid Public Key");
            }

            using (var rsaProvider = new RSACryptoServiceProvider())
            {
                var inputBytes = Encoding.UTF8.GetBytes(m_strEncryptString);//有含义的字符串转化为字节流
                rsaProvider.FromXmlString(ConvertToXmlPublicJavaKey(xmlPublicKey));//载入公钥
                int bufferSize = (rsaProvider.KeySize / 8) - 11;//单块最大长度
                var buffer = new byte[bufferSize];
                using (MemoryStream inputStream = new MemoryStream(inputBytes),
                     outputStream = new MemoryStream())
                {
                    while (true)
                    { //分段加密
                        int readSize = inputStream.Read(buffer, 0, bufferSize);
                        if (readSize <= 0)
                        {
                            break;
                        }

                        var temp = new byte[readSize];
                        Array.Copy(buffer, 0, temp, 0, readSize);
                        var encryptedBytes = rsaProvider.Encrypt(temp, false);
                        outputStream.Write(encryptedBytes, 0, encryptedBytes.Length);
                    }
                    return Convert.ToBase64String(outputStream.ToArray());//转化为字节流方便传输
                }
            }
        }
        /// <summary>
        /// RSA解密
        /// </summary>
        /// <param name="privateKeyJava"></param>
        /// <param name="content"></param>
        /// <returns></returns>
        public static string DecryptJava(string privateKeyJava, string data, string encoding = "UTF-8")
        {
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            byte[] cipherbytes;
            rsa.FromXmlString(ConvertToXmlPrivateKey(privateKeyJava));
            cipherbytes = rsa.Decrypt(Convert.FromBase64String(data), false);

            return Encoding.GetEncoding(encoding).GetString(cipherbytes);
        }
         


        /// <summary>
        /// 把java的公钥转换成.net的xml格式
        /// </summary>
        /// <param name="publicJavaKey">java提供的第三方公钥</param>
        /// <returns></returns>
        public static string ConvertToXmlPublicJavaKey(string publicJavaKey)
        {
            RsaKeyParameters publicKeyParam = (RsaKeyParameters)PublicKeyFactory.CreateKey(Convert.FromBase64String(publicJavaKey));
            string xmlpublicKey = string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent></RSAKeyValue>",
              Convert.ToBase64String(publicKeyParam.Modulus.ToByteArrayUnsigned()),
              Convert.ToBase64String(publicKeyParam.Exponent.ToByteArrayUnsigned()));
            return xmlpublicKey;
        }
        // <summary>
        ///  把java的私钥转换成.net的xml格式
        /// </summary>
        /// <param name="privateJavaKey"></param>
        /// <returns></returns>
        public static string ConvertToXmlPrivateKey(string privateJavaKey)
        {
            RsaPrivateCrtKeyParameters privateKeyParam = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(Convert.FromBase64String(privateJavaKey));
            string xmlPrivateKey = string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent><P>{2}</P><Q>{3}</Q><DP>{4}</DP><DQ>{5}</DQ><InverseQ>{6}</InverseQ><D>{7}</D></RSAKeyValue>",
                         Convert.ToBase64String(privateKeyParam.Modulus.ToByteArrayUnsigned()),
                         Convert.ToBase64String(privateKeyParam.PublicExponent.ToByteArrayUnsigned()),
                         Convert.ToBase64String(privateKeyParam.P.ToByteArrayUnsigned()),
                         Convert.ToBase64String(privateKeyParam.Q.ToByteArrayUnsigned()),
                         Convert.ToBase64String(privateKeyParam.DP.ToByteArrayUnsigned()),
                         Convert.ToBase64String(privateKeyParam.DQ.ToByteArrayUnsigned()),
                         Convert.ToBase64String(privateKeyParam.QInv.ToByteArrayUnsigned()),
                         Convert.ToBase64String(privateKeyParam.Exponent.ToByteArrayUnsigned()));
            return xmlPrivateKey;
        }
    }