using System; using System.Collections.Generic; using System.Globalization; using System.IO; using System.Security.Cryptography; using System.Text; /// <summary> /// 加解密 /// </summary> public static class CryptHelper {     #region RSA加密     /// <summary>     /// 用指定公钥加密文本     /// </summary>     /// <param name="publicKey">公钥</param>     /// <param name="input">文本</param>     /// <returns></returns>     public static string RsaEncrypt(string publicKey, string input)     {         const string sFormat =             "<RSAKeyValue><Modulus>{0}</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";         var provider = new RSACryptoServiceProvider();         var arrPubKey = Hex2Bytes(publicKey);         var pkB64 = Convert.ToBase64String(arrPubKey);         var xmlStr = string.Format(sFormat, pkB64);         var bytesInput = Encoding.UTF8.GetBytes(input);         provider.FromXmlString(xmlStr);         var encryptArray = provider.Encrypt(bytesInput, false);         var hexStr = BitConverter.ToString(encryptArray).Replace("-", "");         return hexStr.ToLower();     }     #endregion     #region 公用函数     /// <summary>     /// 将字节转换成16进制数字     /// </summary>     /// <param name="bytes">字节数组</param>     /// <returns></returns>     public static string Bytes2Hex(byte[] bytes)     {         var buffer = new StringBuilder();         foreach (var t in bytes)         {             buffer.AppendFormat("{0:x2}", t);         }         return buffer.ToString();     }     /// <summary>     /// 将16进制数组转换成字节     /// </summary>     /// <param name="input">16进制数组</param>     /// <returns></returns>     /// <exception cref="ArgumentOutOfRangeException"></exception>     public static byte[] Hex2Bytes(string input)     {         if (string.IsNullOrEmpty(input)) return null;         var offset = input.Length%2;         if (offset == 1) input = "0" + input;         int i;         var list = new List<byte>();         for (i = 0; i < input.Length; i += 2)         {             var temp = input.Substring(i, 2);             byte bv;             var success = byte.TryParse(temp, NumberStyles.HexNumber, null, out bv);             if (!success) throw new ArgumentOutOfRangeException();             list.Add(bv);         }         return list.ToArray();     }     #endregion     #region SHA1加密     /// <summary>     /// SHA1加密 使用缺省密钥给字符串加密     /// </summary>     /// <param name="sourceString"></param>     /// <returns></returns>     public static string Sha1Encrypt(string sourceString)     {         var data = Encoding.Default.GetBytes(sourceString);         HashAlgorithm sha = new SHA1CryptoServiceProvider();         var bytes = sha.ComputeHash(data);         return BitConverter.ToString(bytes).Replace("-", "");     }     #endregion     #region DES加解密     /// <summary>     /// DES加密     /// </summary>     /// <param name="pubKey"></param>     /// <param name="input"></param>     /// <returns></returns>     public static string DesEncrypt(string pubKey, string input)     {         var des = new DESCryptoServiceProvider();         var bytes = Encoding.UTF8.GetBytes(input);         des.Key = Encoding.ASCII.GetBytes(pubKey);         des.IV = Encoding.ASCII.GetBytes(pubKey);         using (var ms = new MemoryStream())         {             using (var cryptoStream = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))             {                 cryptoStream.Write(bytes, 0, bytes.Length);                 cryptoStream.FlushFinalBlock();             }             var data = ms.ToArray();             return BitConverter.ToString(data).Replace("-", "");         }     }     /// <summary>     /// DES解密     /// </summary>     /// <param name="pubKey"></param>     /// <param name="input"></param>     /// <returns></returns>     public static string DesDecrypt(string pubKey, string input)     {         var des = new DESCryptoServiceProvider();         var bytes = Hex2Bytes(input);         des.Key = Encoding.ASCII.GetBytes(pubKey);         des.IV = Encoding.ASCII.GetBytes(pubKey);         using (var ms = new MemoryStream())         {             using (var cryptoStream = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))             {                 cryptoStream.Write(bytes, 0, bytes.Length);                 cryptoStream.FlushFinalBlock();             }             var data = ms.ToArray();             return Encoding.UTF8.GetString(data);         }     }     #endregion     #region MD5加密     /// <summary>     /// MD5加密     /// </summary>     /// <param name="input">输入</param>     /// <returns></returns>     public static string Md5Encrypt(string input)     {         MD5 md5 = new MD5CryptoServiceProvider();         var data = Encoding.UTF8.GetBytes(input);         var encs = md5.ComputeHash(data);         return BitConverter.ToString(encs).Replace("-", "");     }     #endregion }