c# 加密转载 备忘

public sealed class EncryptUtils

    {

        #region Base64加密解密

        /// <summary>

        /// Base64加密

        /// </summary>

        /// <param name="input">需要加密的字符串</param>

        /// <returns></returns>

        public static string Base64Encrypt(string input)

        {

            return Base64Encrypt(input, new UTF8Encoding());

        }

        /// <summary>

        /// Base64加密

        /// </summary>

        /// <param name="input">需要加密的字符串</param>

        /// <param name="encode">字符编码</param>

        /// <returns></returns>

        public static string Base64Encrypt(string input, Encoding encode)

        {

            return Convert.ToBase64String(encode.GetBytes(input));

        }

        /// <summary>

        /// Base64解密

        /// </summary>

        /// <param name="input">需要解密的字符串</param>

        /// <returns></returns>

        public static string Base64Decrypt(string input)

        {

            return Base64Decrypt(input, new UTF8Encoding());

        }

        /// <summary>

        /// Base64解密

        /// </summary>

        /// <param name="input">需要解密的字符串</param>

        /// <param name="encode">字符的编码</param>

        /// <returns></returns>

        public static string Base64Decrypt(string input, Encoding encode)

        {

            return encode.GetString(Convert.FromBase64String(input));

        }

        #endregion

        #region DES加密解密

        /// <summary>

        /// DES加密

        /// </summary>

        /// <param name="data">加密数据</param>

        /// <param name="key">8位字符的密钥字符串</param>

        /// <param name="iv">8位字符的初始化向量字符串</param>

        /// <returns></returns>

        public static string DESEncrypt(string data, string key, string iv)

        {

            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key);

            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv);

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();

            int i = cryptoProvider.KeySize;

            MemoryStream ms = new MemoryStream();

            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);

            StreamWriter sw = new StreamWriter(cst);

            sw.Write(data);

            sw.Flush();

            cst.FlushFinalBlock();

            sw.Flush();

            return Convert.ToBase64String(ms.GetBuffer(), , (int)ms.Length);

        }

        /// <summary>

        /// DES解密

        /// </summary>

        /// <param name="data">解密数据</param>

        /// <param name="key">8位字符的密钥字符串(需要和加密时相同)</param>

        /// <param name="iv">8位字符的初始化向量字符串(需要和加密时相同)</param>

        /// <returns></returns>

        public static string DESDecrypt(string data, string key, string iv)

        {

            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(key);

            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(iv);

            byte[] byEnc;

            try

            {

                byEnc = Convert.FromBase64String(data);

            }

            catch

            {

                return null;

            }

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();

            MemoryStream ms = new MemoryStream(byEnc);

            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);

            StreamReader sr = new StreamReader(cst);

            return sr.ReadToEnd();

        }

        #endregion

        #region MD5加密

        /// <summary>

        /// MD5加密

        /// </summary>

        /// <param name="input">需要加密的字符串</param>

        /// <returns></returns>

        public static string MD5Encrypt(string input)

        {

            return MD5Encrypt(input, new UTF8Encoding());

        }

        /// <summary>

        /// MD5加密

        /// </summary>

        /// <param name="input">需要加密的字符串</param>

        /// <param name="encode">字符的编码</param>

        /// <returns></returns>

        public static string MD5Encrypt(string input, Encoding encode)

        {

            MD5 md5 = new MD5CryptoServiceProvider();

            byte[] t = md5.ComputeHash(encode.GetBytes(input));

            StringBuilder sb = new StringBuilder();

            for (int i = ; i < t.Length; i++)

                sb.Append(t[i].ToString("x").PadLeft(, ''));

            return sb.ToString();

        }

        /// <summary>

        /// MD5对文件流加密

        /// </summary>

        /// <param name="sr"></param>

        /// <returns></returns>

        public static string MD5Encrypt(Stream stream)

        {

            MD5 md5serv = MD5CryptoServiceProvider.Create();

            byte[] buffer = md5serv.ComputeHash(stream);

            StringBuilder sb = new StringBuilder();

            foreach (byte var in buffer)

                sb.Append(var.ToString("x2"));

            return sb.ToString();

        }

        /// <summary>

        /// MD5加密(返回16位加密串)

        /// </summary>

        /// <param name="input"></param>

        /// <param name="encode"></param>

        /// <returns></returns>

        public static string MD5Encrypt16(string input, Encoding encode)

        {

            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();

            string result = BitConverter.ToString(md5.ComputeHash(encode.GetBytes(input)), , );

            result = result.Replace("-", "");

            return result;

        }

        #endregion

        #region 3DES 加密解密

        public static string DES3Encrypt(string data, string key)

        {

            TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();

            DES.Key = ASCIIEncoding.ASCII.GetBytes(key);

            DES.Mode = CipherMode.CBC;

            DES.Padding = PaddingMode.PKCS7;

            ICryptoTransform DESEncrypt = DES.CreateEncryptor();

            byte[] Buffer = ASCIIEncoding.ASCII.GetBytes(data);

            return Convert.ToBase64String(DESEncrypt.TransformFinalBlock(Buffer, , Buffer.Length));

        }

        public static string DES3Decrypt(string data, string key)

        {

            TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();

            DES.Key = ASCIIEncoding.ASCII.GetBytes(key);

            DES.Mode = CipherMode.CBC;

            DES.Padding = System.Security.Cryptography.PaddingMode.PKCS7;

            ICryptoTransform DESDecrypt = DES.CreateDecryptor();

            string result = "";

            try

            {

                byte[] Buffer = Convert.FromBase64String(data);

                result = ASCIIEncoding.ASCII.GetString(DESDecrypt.TransformFinalBlock(Buffer, , Buffer.Length));

            }

            catch (Exception e)

            {

            }

            return result;

        }

        #endregion

    }

转自：http://www.cnblogs.com/malaohu/archive/2013/07/25/3214136.html