Web開発常用暗号化・復号支援クラス

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

namespace WebSite.Utility
{
    public class Encryptor
    {
        #region ===========================DES ===================================
       
        private static string key = "key";
        /// <summary>
        ///  
        /// </summary>
        /// <param name="text"></param>
        /// <returns></returns>
        public static string DESEncrypt(string text)
        {
            return DESEncrypt(text, key);
        }
        /// <summary>
        /// DES 
        /// </summary>
        /// <param name="text"> </param>
        /// <param name="sKey"> </param>
        /// <returns> </returns>
        public static string DESEncrypt(string text,string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray;
            inputByteArray = Encoding.Default.GetBytes(text);
            des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
            des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
            System.IO.MemoryStream ms = new System.IO.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);
            }
            ms.Dispose();
            cs.Dispose();
            return ret.ToString();

        }
        /// <summary>
        /// DES ， 
        /// </summary>
        /// <param name="text"> </param>
        /// <returns> </returns>
        public static string DESDecrypt(string text)
        {
            return DESDecrypt(text,key);
        }
        /// <summary>
        /// DES 
        /// </summary>
        /// <param name="text"> </param>
        /// <param name="sKey"> </param>
        /// <returns> </returns>
        public static string DESDecrypt(string text,string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            int len;
            len = text.Length / 2;
            byte[] inputByteArray = new byte[len];
            int x, i;
            for (x = 0; x < len; x++)
            {
                i = Convert.ToInt32(text.Substring(x * 2, 2), 16);
                inputByteArray[x] = (byte)i;
            }
            try
            {
                des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
                des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                string estring = Encoding.Default.GetString(ms.ToArray());
                ms.Dispose();
                cs.Dispose();
                return estring;
            }
            catch
            {
                return "";
            }

        } 
        #endregion

        #region ==============================MD5 ==================================
        /// <summary>
        ///  MD5 Hash 
        /// </summary>
        /// <param name="text"> </param>
        /// <returns> </returns>
        public static string MD5Encrypt(string text)
        {
            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(text, "MD5");
        } 
        #endregion============================================================


        #region =============================SHA1==============================

        /// <summary>
        ///  SHA1 Hash 
        /// </summary>
        /// <param name="text"> </param>
        /// <returns> </returns>
        public static string SHA1Encrypt(string text)
        {
            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(text, "SHA1");
        } 
        #endregion=============================================================



    }
}