C# 常用加密解密方法

字符串加密分可逆和不可逆加密两种，下面直接贴上代码

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

namespace Operator.CommonOp
{
    /// <summary>
    /// 字符串加密。
    /// </summary>
    public class StringSecurity
    {
        /// <summary>
        /// MD5加密。
        /// </summary>
        public static string MD5Encrypt(string originalString)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] palindata = Encoding.Default.GetBytes(originalString);
            byte[] encryptdata = md5.ComputeHash(palindata);

            return Convert.ToBase64String(encryptdata);
        }

        /// <summary>
        /// RAS加密。
        /// </summary>
        public static string RSAEncrypt(string originalString)
        {
            CspParameters param = new CspParameters();
            param.KeyContainerName = "12345";

            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(param))
            {
                byte[] plaindata = Encoding.Default.GetBytes(originalString);
                byte[] encryptdata = rsa.Encrypt(plaindata, false);

                return Convert.ToBase64String(encryptdata);
            }
        }

        /// <summary>
        /// RAS解密。
        /// </summary>
        public static string RSADecrypt(string securitylString)
        {
            CspParameters param = new CspParameters();
            param.KeyContainerName = "12345";
            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(param))
            {
                byte[] encryptdata = Convert.FromBase64String(securitylString);
                byte[] decryptdata = rsa.Decrypt(encryptdata, false);
                return Encoding.Default.GetString(decryptdata);
            }
        }

        /// <summary>
        /// DES加密。
        /// </summary>
        public static string DESEncrypt(string originalString)
        {
            string securtyString = null;
            string key = "12345678";
            string iv = "87654321";
            byte[] btKey = Encoding.UTF8.GetBytes(key);
            byte[] btIV = Encoding.UTF8.GetBytes(iv);
            byte[] inData = Encoding.UTF8.GetBytes(originalString);

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream();            
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write);

            cs.Write(inData, 0, inData.Length);
            cs.FlushFinalBlock();

            securtyString = Convert.ToBase64String(ms.ToArray());
            cs.Close();
            ms.Close();

            return securtyString;
        }

        /// <summary>
        /// DES解密。
        /// </summary>
        public static string DESDecrypt(string securityString)
        {
            byte[] inData = null;
            try
            {
                inData = Convert.FromBase64String(securityString);
            }
            catch (Exception)
            {
                return null;
            } 

            string originalString = null;
            string key = "12345678";
            string iv = "87654321";
            byte[] btKey = Encoding.UTF8.GetBytes(key);
            byte[] btIV = Encoding.UTF8.GetBytes(iv);

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write);

            cs.Write(inData, 0, inData.Length);
            try
            {
                cs.FlushFinalBlock();
            }
            catch (Exception)
            {
                ms.Close();
                return null;
            }
            

            originalString = Encoding.UTF8.GetString(ms.ToArray()); 
            cs.Close();
            ms.Close();

            return originalString;
        }        
    }
}