C# Base64编码解码 ，Md5加密、Rsa加密解密

一、引用
using System.Security.Cryptography;
using System.Text;

二、方法使用

1.MD5 16位加密 

 /**//// <summary>
        /// MD5 16位加密 加密后密码为小写
        /// </summary>
        /// <param name="ConvertString"></param>
        /// <returns></returns>
        public static string GetMd5Str(string ConvertString)
        {
             MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8);
             t2 = t2.Replace("-", "");

            t2 = t2.ToLower();

             return t2;
         }

2. MD5　32位加密

 /**//// <summary>
        /// MD5　32位加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
       static  string UserMd5(string str)
        {
            string cl = str;
            string pwd = "";
             MD5 md5 = MD5.Create();//实例化一个md5对像
            // 加密后是一个字节类型的数组，这里要注意编码UTF8/Unicode等的选择　
            byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(cl));
            // 通过使用循环，将字节类型的数组转换为字符串，此字符串是常规字符格式化所得
            for (int i = 0; i < s.Length; i++)
            {
                // 将得到的字符串使用十六进制类型格式。格式后的字符是小写的字母，如果使用大写（X）则格式后的字符是大写字符

                 pwd = pwd + s[i].ToString("X");
                
             }
            return pwd;
         }

3.C# Base64编码解码 ，Md5、Rsa加密解密

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace ClassLibrary1
{
    class Code
    {
        //1、base64  to  string
        public static string Base64Encrypt(string strPath)
        {
            byte[] bpath = Convert.FromBase64String(strPath);
            string returnData = Encoding.Default.GetString(bpath);
            return returnData;
        }


        //2、string   to  base64
        public static string Base64DesEncrypt(string strPath)
        {
            Encoding encode = Encoding.ASCII;
            byte[] bytedata = encode.GetBytes(strPath);
            string returnData = Convert.ToBase64String(bytedata, 0, bytedata.Length);
            return returnData;
        }

        /// <summary>
        /// 对字符串进MD5加密
        /// </summary>
        /// <param name="sourceStr">源类型</param>
        /// <returns>加密后字符串</returns>
        public static string Md5Encrypt(string sourceStr)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            //将要加密的字符串转换成字节数组
            byte[] palindata = Encoding.Default.GetBytes(sourceStr);
            //通过字节数组进行加密
            byte[] encryptdata = md5.ComputeHash(palindata);
            //将加密后的字节数组转换成字符串
            string returnData = Convert.ToBase64String(encryptdata);
            return returnData;
        }

        /// <summary>
        ///  Md5加密
        /// </summary>
        /// <param name="pToEncrypt">要加密的string</param>
        /// <param name="sKey">要加密的key</param>
        /// <returns></returns>
        public static string Md5Encrypt(string pToEncrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            des.Key = Encoding.ASCII.GetBytes(sKey);
            des.IV = Encoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            var s = ret.ToString();
            return s;
        }
        
        /// <summary>
        ///  Md5解密
        /// </summary>
        /// <param name="pToDecrypt">解密string</param>
        /// <param name="sKey">解密key(要8位数)</param>
        /// <returns></returns>
        public static string Md5Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte) i;
            }
            des.Key = Encoding.ASCII.GetBytes(sKey);
            des.IV = Encoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            return Encoding.Default.GetString(ms.ToArray());
        }


        public static CspParameters Param;
        /// <summary>
        /// 进行 RSA 加密
        /// </summary>
        /// <param name="sourceStr">源字符串</param>
        /// <returns>加密后字符串</returns>
        public static string RsaEncrypt(string sourceStr)
        {
            Param = new CspParameters();
            //密匙容器的名称，保持加密解密一致才能解密成功
            Param.KeyContainerName = "Navis";
            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(Param))
            {
                //将要加密的字符串转换成字节数组
                byte[] plaindata = Encoding.Default.GetBytes(sourceStr);
                //通过字节数组进行加密
                byte[] encryptdata = rsa.Encrypt(plaindata, false);
                //将加密后的字节数组转换成字符串
                return Convert.ToBase64String(encryptdata);
            }
        }

        /// <summary>
        /// 通过RSA 加密方式进行解密
        /// </summary>
        /// <param name="codingStr">加密字符串</param>
        /// <returns>解密后字符串</returns>
        public static string RsaDesEncrypt(string codingStr)
        {
            Param = new CspParameters();
            Param.KeyContainerName = "Navis";
            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(Param))
            {
                byte[] encryptdata = Convert.FromBase64String(codingStr);
                byte[] decryptdata = rsa.Decrypt(encryptdata, false);
                return Encoding.Default.GetString(decryptdata);
            }
        }
    }
}