C#工具:加密解密帮助类

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
//加密字符串,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
//public string DesEncrypt(string strText, string strEncrKey) 

//解密字符串,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
//public string DesDecrypt(string strText,string sDecrKey) 

//加密数据文件,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
//public void DesEncrypt(string m_InFilePath,string m_OutFilePath,string strEncrKey) 

//解密数据文件,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
//public void DesDecrypt(string m_InFilePath,string m_OutFilePath,string sDecrKey) 

//MD5加密
//public string MD5Encrypt(string strText)
using Common;

namespace Commons
{
    /// <summary>
    /// DES对称加解密、AES RijndaelManaged加解密、Base64加密解密、MD5加密等操作辅助类
    /// </summary>
    public sealed class EncodeHelper
    {
        #region DES对称加密解密
        public const string DEFAULT_ENCRYPT_KEY = "";

        /// <summary>
        /// 使用默认加密
        /// </summary>
        /// <param name="strText"></param>
        /// <returns></returns>
        public static string DesEncrypt(string strText)
        {
            try
            {
                return DesEncrypt(strText, DEFAULT_ENCRYPT_KEY);
            }
            catch
            {
                return "";
            }
        }

        /// <summary>
        /// 使用默认解密
        /// </summary>
        /// <param name="strText"></param>
        /// <returns></returns>
        public static string DesDecrypt(string strText)
        {
            try
            {
                return DesDecrypt(strText, DEFAULT_ENCRYPT_KEY);
            }
            catch
            {
                return "";
            }
        }

        /// <summary>
        /// Encrypt the string
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="strText">string</param>
        /// <param name="strEncrKey">key</param>
        /// <returns></returns>
        public static string DesEncrypt(string strText, string strEncrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

            byKey = Encoding.UTF8.GetBytes(strEncrKey.Substring(, ));
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.UTF8.GetBytes(strText);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write);
            cs.Write(inputByteArray, , inputByteArray.Length);
            cs.FlushFinalBlock();
            return Convert.ToBase64String(ms.ToArray());
        }

        /// <summary>
        /// Decrypt string
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="strText">Decrypt string</param>
        /// <param name="sDecrKey">key</param>
        /// <returns>output string</returns>
        public static string DesDecrypt(string strText, string sDecrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            byte[] inputByteArray = new Byte[strText.Length];

            byKey = Encoding.UTF8.GetBytes(sDecrKey.Substring(, ));
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            inputByteArray = Convert.FromBase64String(strText);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);
            cs.Write(inputByteArray, , inputByteArray.Length);
            cs.FlushFinalBlock();
            Encoding encoding = new UTF8Encoding();
            return encoding.GetString(ms.ToArray());
        }

        /// <summary>
        /// Encrypt files
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="m_InFilePath">Encrypt file path</param>
        /// <param name="m_OutFilePath">output file</param>
        /// <param name="strEncrKey">key</param>
        public static void DesEncrypt(string m_InFilePath, string m_OutFilePath, string strEncrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

            byKey = Encoding.UTF8.GetBytes(strEncrKey.Substring(, ));
            FileStream fin = new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
            FileStream fout = new FileStream(m_OutFilePath, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength();
            //Create variables to help with read and write.
            byte[] bin = new byte[]; //This is intermediate storage for the encryption.
            long rdlen = ; //This is the total number of bytes written.
            long totlen = fin.Length; //This is the total length of the input file.
            int len; //This is the number of bytes to be written at a time. 

            DES des = new DESCryptoServiceProvider();
            CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write);

            //Read from the input file, then encrypt and write to the output file.
            while (rdlen < totlen)
            {
                len = fin.Read(bin, , );
                encStream.Write(bin, , len);
                rdlen = rdlen + len;
            }
            encStream.Close();
            fout.Close();
            fin.Close();
        }

        /// <summary>
        /// Decrypt files
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="m_InFilePath">Decrypt filepath</param>
        /// <param name="m_OutFilePath">output filepath</param>
        /// <param name="sDecrKey">key</param>
        public static void DesDecrypt(string m_InFilePath, string m_OutFilePath, string sDecrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

            byKey = Encoding.UTF8.GetBytes(sDecrKey.Substring(, ));
            FileStream fin = new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
            FileStream fout = new FileStream(m_OutFilePath, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength();
            //Create variables to help with read and write.
            byte[] bin = new byte[]; //This is intermediate storage for the encryption.
            long rdlen = ; //This is the total number of bytes written.
            long totlen = fin.Length; //This is the total length of the input file.
            int len; //This is the number of bytes to be written at a time. 

            DES des = new DESCryptoServiceProvider();
            CryptoStream encStream = new CryptoStream(fout, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);

            //Read from the input file, then encrypt and write to the output file.
            while (rdlen < totlen)
            {
                len = fin.Read(bin, , );
                encStream.Write(bin, , len);
                rdlen = rdlen + len;
            }
            encStream.Close();
            fout.Close();
            fin.Close();
        }
        #endregion

        #region 对称加密算法AES RijndaelManaged加密解密
        private static readonly string Default_AES_Key = "@#kim123";
        private static byte[] Keys = { 0x41, 0x72, 0x65, 0x79, 0x6F, 0x75, 0x6D, 0x79,
                                             0x53,0x6E, 0x6F, 0x77, 0x6D, 0x61, 0x6E, 0x3F };

        /// <summary>
        /// 对称加密算法AES RijndaelManaged加密(RijndaelManaged（AES）算法是块式加密算法)
        /// </summary>
        /// <param name="encryptString">待加密字符串</param>
        /// <returns>加密结果字符串</returns>
        public static string AES_Encrypt(string encryptString)
        {
            return AES_Encrypt(encryptString, Default_AES_Key);
        }

        /// <summary>
        /// 对称加密算法AES RijndaelManaged加密(RijndaelManaged（AES）算法是块式加密算法)
        /// </summary>
        /// <param name="encryptString">待加密字符串</param>
        /// <param name="encryptKey">加密密钥，须半角字符</param>
        /// <returns>加密结果字符串</returns>
        public static string AES_Encrypt(string encryptString, string encryptKey)
        {
            encryptKey = GetSubString(encryptKey, , "");
            encryptKey = encryptKey.PadRight(, ' ');

            RijndaelManaged rijndaelProvider = new RijndaelManaged();
            rijndaelProvider.Key = Encoding.UTF8.GetBytes(encryptKey.Substring(, ));
            rijndaelProvider.IV = Keys;
            ICryptoTransform rijndaelEncrypt = rijndaelProvider.CreateEncryptor();

            byte[] inputData = Encoding.UTF8.GetBytes(encryptString);
            byte[] encryptedData = rijndaelEncrypt.TransformFinalBlock(inputData, , inputData.Length);

            return Convert.ToBase64String(encryptedData);
        }

        /// <summary>
        /// 对称加密算法AES RijndaelManaged解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <returns>解密成功返回解密后的字符串,失败返源串</returns>
        public static string AES_Decrypt(string decryptString)
        {
            return AES_Decrypt(decryptString, Default_AES_Key);
        }

        /// <summary>
        /// 对称加密算法AES RijndaelManaged解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <param name="decryptKey">解密密钥,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串,失败返回空</returns>
        public static string AES_Decrypt(string decryptString, string decryptKey)
        {
            try
            {
                decryptKey = GetSubString(decryptKey, , "");
                decryptKey = decryptKey.PadRight(, ' ');

                RijndaelManaged rijndaelProvider = new RijndaelManaged();
                rijndaelProvider.Key = Encoding.UTF8.GetBytes(decryptKey);
                rijndaelProvider.IV = Keys;
                ICryptoTransform rijndaelDecrypt = rijndaelProvider.CreateDecryptor();

                byte[] inputData = Convert.FromBase64String(decryptString);
                byte[] decryptedData = rijndaelDecrypt.TransformFinalBlock(inputData, , inputData.Length);

                return Encoding.UTF8.GetString(decryptedData);
            }
            catch
            {
                return string.Empty;
            }
        }

        /// <summary>
        /// 按字节长度(按字节,一个汉字为2个字节)取得某字符串的一部分
        /// </summary>
        /// <param name="sourceString">源字符串</param>
        /// <param name="length">所取字符串字节长度</param>
        /// <param name="tailString">附加字符串(当字符串不够长时，尾部所添加的字符串，一般为"...")</param>
        /// <returns>某字符串的一部分</returns>
        private static string GetSubString(string sourceString, int length, string tailString)
        {
            return GetSubString(sourceString, , length, tailString);
        }

        /// <summary>
        /// 按字节长度(按字节,一个汉字为2个字节)取得某字符串的一部分
        /// </summary>
        /// <param name="sourceString">源字符串</param>
        /// <param name="startIndex">索引位置，以0开始</param>
        /// <param name="length">所取字符串字节长度</param>
        /// <param name="tailString">附加字符串(当字符串不够长时，尾部所添加的字符串，一般为"...")</param>
        /// <returns>某字符串的一部分</returns>
        private static string GetSubString(string sourceString, int startIndex, int length, string tailString)
        {
            string myResult = sourceString;

            //当是日文或韩文时(注:中文的范围:\u4e00 - \u9fa5, 日文在\u0800 - \u4e00, 韩文为\xAC00-\xD7A3)
            if (System.Text.RegularExpressions.Regex.IsMatch(sourceString, "[\u0800-\u4e00]+") ||
                System.Text.RegularExpressions.Regex.IsMatch(sourceString, "[\xAC00-\xD7A3]+"))
            {
                //当截取的起始位置超出字段串长度时
                if (startIndex >= sourceString.Length)
                {
                    return string.Empty;
                }
                else
                {
                    return sourceString.Substring(startIndex,
                                                   ((length + startIndex) > sourceString.Length) ? (sourceString.Length - startIndex) : length);
                }
            }

            //中文字符，如"中国人民abcd123"
            if (length <= )
            {
                return string.Empty;
            }
            byte[] bytesSource = Encoding.Default.GetBytes(sourceString);

            //当字符串长度大于起始位置
            if (bytesSource.Length > startIndex)
            {
                int endIndex = bytesSource.Length;

                //当要截取的长度在字符串的有效长度范围内
                if (bytesSource.Length > (startIndex + length))
                {
                    endIndex = length + startIndex;
                }
                else
                {   //当不在有效范围内时,只取到字符串的结尾
                    length = bytesSource.Length - startIndex;
                    tailString = "";
                }

                int[] anResultFlag = new int[length];
                int nFlag = ;
                //字节大于127为双字节字符
                for (int i = startIndex; i < endIndex; i++)
                {
                    if (bytesSource[i] > )
                    {
                        nFlag++;
                        if (nFlag == )
                        {
                            nFlag = ;
                        }
                    }
                    else
                    {
                        nFlag = ;
                    }
                    anResultFlag[i] = nFlag;
                }
                //最后一个字节为双字节字符的一半
                if ((bytesSource[endIndex - ] > ) && (anResultFlag[length - ] == ))
                {
                    length = length + ;
                }

                byte[] bsResult = new byte[length];
                Array.Copy(bytesSource, startIndex, bsResult, , length);
                myResult = Encoding.Default.GetString(bsResult);
                myResult = myResult + tailString;

                return myResult;
            }

            return string.Empty;

        }

        /// <summary>
        /// 加密文件流
        /// </summary>
        /// <param name="fs"></param>
        /// <returns></returns>
        public static CryptoStream AES_EncryptStrream(FileStream fs, string decryptKey)
        {
            decryptKey = GetSubString(decryptKey, , "");
            decryptKey = decryptKey.PadRight(, ' ');

            RijndaelManaged rijndaelProvider = new RijndaelManaged();
            rijndaelProvider.Key = Encoding.UTF8.GetBytes(decryptKey);
            rijndaelProvider.IV = Keys;

            ICryptoTransform encrypto = rijndaelProvider.CreateEncryptor();
            CryptoStream cytptostreamEncr = new CryptoStream(fs, encrypto, CryptoStreamMode.Write);
            return cytptostreamEncr;
        }

        /// <summary>
        /// 解密文件流
        /// </summary>
        /// <param name="fs"></param>
        /// <returns></returns>
        public static CryptoStream AES_DecryptStream(FileStream fs, string decryptKey)
        {
            decryptKey = GetSubString(decryptKey, , "");
            decryptKey = decryptKey.PadRight(, ' ');

            RijndaelManaged rijndaelProvider = new RijndaelManaged();
            rijndaelProvider.Key = Encoding.UTF8.GetBytes(decryptKey);
            rijndaelProvider.IV = Keys;
            ICryptoTransform Decrypto = rijndaelProvider.CreateDecryptor();
            CryptoStream cytptostreamDecr = new CryptoStream(fs, Decrypto, CryptoStreamMode.Read);
            return cytptostreamDecr;
        }

        /// <summary>
        /// 对指定文件加密
        /// </summary>
        /// <param name="InputFile"></param>
        /// <param name="OutputFile"></param>
        /// <returns></returns>
        public static bool AES_EncryptFile(string InputFile, string OutputFile)
        {
            try
            {
                string decryptKey = "www.iqidi.com";

                FileStream fr = new FileStream(InputFile, FileMode.Open);
                FileStream fren = new FileStream(OutputFile, FileMode.Create);
                CryptoStream Enfr = AES_EncryptStrream(fren, decryptKey);
                byte[] bytearrayinput = new byte[fr.Length];
                fr.Read(bytearrayinput, , bytearrayinput.Length);
                Enfr.Write(bytearrayinput, , bytearrayinput.Length);
                Enfr.Close();
                fr.Close();
                fren.Close();
            }
            catch
            {
                //文件异常
                return false;
            }
            return true;
        }

        /// <summary>
        /// 对指定的文件解压缩
        /// </summary>
        /// <param name="InputFile"></param>
        /// <param name="OutputFile"></param>
        /// <returns></returns>
        public static bool AES_DecryptFile(string InputFile, string OutputFile)
        {
            try
            {
                string decryptKey = "www.iqidi.com";
                FileStream fr = new FileStream(InputFile, FileMode.Open);
                FileStream frde = new FileStream(OutputFile, FileMode.Create);
                CryptoStream Defr = AES_DecryptStream(fr, decryptKey);
                byte[] bytearrayoutput = new byte[];
                int m_count = ;

                do
                {
                    m_count = Defr.Read(bytearrayoutput, , bytearrayoutput.Length);
                    frde.Write(bytearrayoutput, , m_count);
                    if (m_count < bytearrayoutput.Length)
                        break;
                } while (true);

                Defr.Close();
                fr.Close();
                frde.Close();
            }
            catch
            {
                //文件异常
                return false;
            }
            return true;
        }

        #endregion

        #region Base64加密解密
        /// <summary>
        /// Base64是一種使用64基的位置計數法。它使用2的最大次方來代表僅可列印的ASCII 字元。
        /// 這使它可用來作為電子郵件的傳輸編碼。在Base64中的變數使用字元A-Z、a-z和0-9 ，
        /// 這樣共有62個字元，用來作為開始的64個數字，最後兩個用來作為數字的符號在不同的
        /// 系統中而不同。
        /// Base64加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string Base64Encrypt(string str)
        {
            byte[] encbuff = System.Text.Encoding.UTF8.GetBytes(str);
            return Convert.ToBase64String(encbuff);
        }

        /// <summary>
        /// Base64解密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string Base64Decrypt(string str)
        {
            byte[] decbuff = Convert.FromBase64String(str);
            return System.Text.Encoding.UTF8.GetString(decbuff);
        }
        #endregion

        #region MD5加密
        /// <summary>
        /// MD5 Encrypt
        /// </summary>
        /// <param name="strText">text</param>
        /// <returns>md5 Encrypt string</returns>
        public static string MD5Encrypt(string strText)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] result = md5.ComputeHash(Encoding.Default.GetBytes(strText));
            return Encoding.Default.GetString(result);
        }

        public static string MD5EncryptHash(String input)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            //the GetBytes method returns byte array equavalent of a string
            byte[] res = md5.ComputeHash(Encoding.Default.GetBytes(input), , input.Length);
            char[] temp = new char[res.Length];
            //copy to a char array which can be passed to a String constructor
            Array.Copy(res, temp, res.Length);
            //return the result as a string
            return new String(temp);
        }

        public static string MD5EncryptHashHex(String input)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            //the GetBytes method returns byte array equavalent of a string
            byte[] res = md5.ComputeHash(Encoding.Default.GetBytes(input), , input.Length);

            String returnThis = string.Empty;

            for (int i = ; i < res.Length; i++)
            {
                returnThis += Uri.HexEscape((char)res[i]);
            }
            returnThis = returnThis.Replace("%", "");
            returnThis = returnThis.ToLower();

            return returnThis;
        }

        /// <summary>
        /// MD5 三次加密算法.计算过程: (QQ使用)
        /// 1. 验证码转为大写
        /// 2. 将密码使用这个方法进行三次加密后,与验证码进行叠加
        /// 3. 然后将叠加后的内容再次MD5一下,得到最终验证码的值
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public static string EncyptMD5_3_16(string s)
        {
            MD5 md5 = MD5CryptoServiceProvider.Create();
            byte[] bytes = System.Text.Encoding.ASCII.GetBytes(s);
            byte[] bytes1 = md5.ComputeHash(bytes);
            byte[] bytes2 = md5.ComputeHash(bytes1);
            byte[] bytes3 = md5.ComputeHash(bytes2);

            StringBuilder sb = new StringBuilder();
            foreach (var item in bytes3)
            {
                sb.Append(item.ToString("x").PadLeft(, ''));
            }
            return sb.ToString().ToUpper();
        }
        #endregion

        /// <summary>
        /// SHA256函数
        /// </summary>
        /// <param name="str">原始字符串</param>
        /// <returns>SHA256结果(返回长度为44字节的字符串)</returns>
        public static string SHA256(string str)
        {
            byte[] SHA256Data = Encoding.UTF8.GetBytes(str);
            SHA256Managed Sha256 = new SHA256Managed();
            byte[] Result = Sha256.ComputeHash(SHA256Data);
            return Convert.ToBase64String(Result);  //返回长度为44字节的字符串
        }

        /// <summary>
        /// 加密字符串
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string EncryptString(string input)
        {
            return MD5Util.AddMD5Profix(Base64Util.Encrypt(MD5Util.AddMD5Profix(input)));
            //return Base64.Encrypt(MD5.AddMD5Profix(Base64.Encrypt(input)));
        }

        /// <summary>
        /// 解密加过密的字符串
        /// </summary>
        /// <param name="input"></param>
        /// <param name="throwException">解密失败是否抛异常</param>
        /// <returns></returns>
        public static string DecryptString(string input, bool throwException)
        {
            string res = "";
            try
            {
                res = input;// Base64.Decrypt(input);
                if (MD5Util.ValidateValue(res))
                {
                    return MD5Util.RemoveMD5Profix(Base64Util.Decrypt(MD5Util.RemoveMD5Profix(res)));
                }
                else
                {
                    throw new Exception("字符串无法转换成功！");
                }
            }
            catch
            {
                if (throwException)
                {
                    throw;
                }
                else
                {
                    return "";
                }
            }
        }
    }
}

AESEncode

using System;
using System.Collections.Generic;
using System.Text;

namespace Common
{
    /// <summary>
    /// 基于Base64的加密编码，
    /// 可以设置不同的密码表来获取不同的编码合解码
    /// </summary>
    public class Base64Util
    {
        public Base64Util()
        {
            this.InitDict();
        }

        protected static Base64Util s_b64 = new Base64Util();

        #region Base64加密解密
        /// <summary>
        /// Base64是一種使用64基的位置計數法。它使用2的最大次方來代表僅可列印的ASCII 字元。
        /// 這使它可用來作為電子郵件的傳輸編碼。在Base64中的變數使用字元A-Z、a-z和0-9 ，
        /// 這樣共有62個字元，用來作為開始的64個數字，最後兩個用來作為數字的符號在不同的
        /// 系統中而不同。
        /// Base64加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string Base64Encrypt(string str)
        {
            byte[] encbuff = System.Text.Encoding.UTF8.GetBytes(str);
            return Convert.ToBase64String(encbuff);
        }

        /// <summary>
        /// Base64解密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string Base64Decrypt(string str)
        {
            byte[] decbuff = Convert.FromBase64String(str);
            return System.Text.Encoding.UTF8.GetString(decbuff);
        }
        #endregion

        /// <summary>
        /// 使用默认的密码表加密字符串
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string Encrypt(string input)
        {
            return s_b64.Encode(input);
        }
        /// <summary>
        /// 使用默认的密码表解密字符串
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string Decrypt(string input)
        {
            return s_b64.Decode(input);
        }

        /// <summary>
        /// 获取具有标准的Base64密码表的加密类
        /// </summary>
        /// <returns></returns>
        public static Base64Util GetStandardBase64()
        {
            Base64Util b64 = new Base64Util();
            b64.Pad = "=";
            b64.CodeTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
            return b64;
        }

        protected string m_codeTable = @"ABCDEFGHIJKLMNOPQRSTUVWXYZbacdefghijklmnopqrstu_wxyz0123456789*-";
        protected string m_pad = "v";
        protected Dictionary<int, char> m_t1 = new Dictionary<int, char>();
        protected Dictionary<char, int> m_t2 = new Dictionary<char, int>();

        /// <summary>
        /// 密码表
        /// </summary>
        public string CodeTable
        {
            get { return m_codeTable; }
            set
            {
                if (value == null)
                {
                    throw new Exception("密码表不能为null");
                }
                else if (value.Length < )
                {
                    throw new Exception("密码表长度必须至少为64");
                }
                else
                {
                    this.ValidateRepeat(value);
                    this.ValidateEqualPad(value, m_pad);
                    m_codeTable = value;
                    this.InitDict();
                }
            }
        }
        /// <summary>
        /// 补码
        /// </summary>
        public string Pad
        {
            get { return m_pad; }
            set
            {
                if (value == null)
                {
                    throw new Exception("密码表的补码不能为null");
                }
                else if (value.Length != )
                {
                    throw new Exception("密码表的补码长度必须为1");
                }
                else
                {
                    this.ValidateEqualPad(m_codeTable, value);
                    m_pad = value;
                    this.InitDict();
                }
            }
        }

        /// <summary>
        /// 返回编码后的字符串
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        public string Encode(string source)
        {
            if (source == null || source == "")
            {
                return "";
            }
            else
            {
                StringBuilder sb = new StringBuilder();
                byte[] tmp = System.Text.UTF8Encoding.UTF8.GetBytes(source);
                int remain = tmp.Length % ;
                int patch =  - remain;
                if (remain != )
                {
                    Array.Resize(ref tmp, tmp.Length + patch);
                }
                int cnt = (int)Math.Ceiling(tmp.Length * 1.0 / );
                for (int i = ; i < cnt; i++)
                {
                    sb.Append(this.EncodeUnit(tmp[i * ], tmp[i *  + ], tmp[i *  + ]));
                }
                if (remain != )
                {
                    sb.Remove(sb.Length - patch, patch);
                    for (int i = ; i < patch; i++)
                    {
                        sb.Append(m_pad);
                    }
                }
                return sb.ToString();
            }

        }
        protected string EncodeUnit(params byte[] unit)
        {
            int[] obj = new int[];
            obj[] = (unit[] & 0xfc) >> ;
            obj[] = ((unit[] & 0x03) << ) + ((unit[] & 0xf0) >> );
            obj[] = ((unit[] & 0x0f) << ) + ((unit[] & 0xc0) >> );
            obj[] = unit[] & 0x3f;
            StringBuilder sb = new StringBuilder();
            for (int i = ; i < obj.Length; i++)
            {
                sb.Append(this.GetEC((int)obj[i]));
            }
            return sb.ToString();
        }
        protected char GetEC(int code)
        {
            return m_t1[code];//m_codeTable[code];
        }

        /// <summary>
        /// 获得解码字符串
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        public string Decode(string source)
        {
            if (source == null || source == "")
            {
                return "";
            }
            else
            {
                List<byte> list = new List<byte>();
                char[] tmp = source.ToCharArray();
                int remain = tmp.Length % ;
                if (remain != )
                {
                    Array.Resize(ref tmp, tmp.Length - remain);
                }
                int patch = source.IndexOf(m_pad);
                if (patch != -)
                {
                    patch = source.Length - patch;
                }
                int cnt = tmp.Length / ;
                for (int i = ; i < cnt; i++)
                {
                    this.DecodeUnit(list, tmp[i * ], tmp[i *  + ], tmp[i *  + ], tmp[i *  + ]);
                }
                for (int i = ; i < patch; i++)
                {
                    list.RemoveAt(list.Count - );
                }
                return System.Text.Encoding.UTF8.GetString(list.ToArray());
            }
        }
        protected void DecodeUnit(List<byte> byteArr, params char[] chArray)
        {
            int[] res = new int[];
            byte[] unit = new byte[chArray.Length];
            for (int i = ; i < chArray.Length; i++)
            {
                unit[i] = this.FindChar(chArray[i]);
            }
            res[] = (unit[] << ) + ((unit[] & 0x30) >> );
            res[] = ((unit[] & 0xf) << ) + ((unit[] & 0x3c) >> );
            res[] = ((unit[] & 0x3) << ) + unit[];
            for (int i = ; i < res.Length; i++)
            {
                byteArr.Add((byte)res[i]);
            }
        }
        protected byte FindChar(char ch)
        {
            int pos = m_t2[ch];//m_codeTable.IndexOf(ch);
            return (byte)pos;
        }

        /// <summary>
        /// 初始化双向哈西字典
        /// </summary>
        protected void InitDict()
        {
            m_t1.Clear();
            m_t2.Clear();
            m_t2.Add(m_pad[], -);
            for (int i = ; i < m_codeTable.Length; i++)
            {
                m_t1.Add(i, m_codeTable[i]);
                m_t2.Add(m_codeTable[i], i);
            }
        }
        /// <summary>
        /// 检查字符串中的字符是否有重复
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        protected void ValidateRepeat(string input)
        {
            for (int i = ; i < input.Length; i++)
            {
                if (input.LastIndexOf(input[i]) > i)
                {
                    throw new Exception("密码表中含有重复字符：" + input[i]);
                }
            }
        }
        /// <summary>
        /// 检查字符串是否包含补码字符
        /// </summary>
        /// <param name="input"></param>
        /// <param name="pad"></param>
        protected void ValidateEqualPad(string input, string pad)
        {
            if (input.IndexOf(pad) > -)
            {
                throw new Exception("密码表中包含了补码字符：" + pad);
            }
        }

        protected void Test()
        {

            //m_codeTable = @"STUVWXYZbacdefghivklABCDEFGHIJKLMNOPQRmnopqrstu!wxyz0123456789+/";
            //m_pad = "j";

            this.InitDict();

            string test = "abc ABC 你好！◎＃￥％……!@#$%^";
            string encode = this.Encode("false");
            string decode = this.Decode(encode);
            Console.WriteLine(encode);
            Console.WriteLine(test == decode);
        }
    }
}

Base64Util

using System;
using System.Security.Cryptography;
using System.Text;
namespace Maticsoft.Common.DEncrypt
{
    /// <summary>
    /// Encrypt 的摘要说明。
    /// LiTianPing
    /// </summary>
    public class DEncrypt
    {
        /// <summary>
        /// 构造方法
        /// </summary>
        public DEncrypt()
        {
        } 

        #region 使用 缺省密钥字符串 加密/解密string

        /// <summary>
        /// 使用缺省密钥字符串加密string
        /// </summary>
        /// <param name="original">明文</param>
        /// <returns>密文</returns>
        public static string Encrypt(string original)
        {
            return Encrypt(original,"MATICSOFT");
        }
        /// <summary>
        /// 使用缺省密钥字符串解密string
        /// </summary>
        /// <param name="original">密文</param>
        /// <returns>明文</returns>
        public static string Decrypt(string original)
        {
            return Decrypt(original,"MATICSOFT",System.Text.Encoding.Default);
        }

        #endregion

        #region 使用 给定密钥字符串 加密/解密string
        /// <summary>
        /// 使用给定密钥字符串加密string
        /// </summary>
        /// <param name="original">原始文字</param>
        /// <param name="key">密钥</param>
        /// <param name="encoding">字符编码方案</param>
        /// <returns>密文</returns>
        public static string Encrypt(string original, string key)
        {
            byte[] buff = System.Text.Encoding.Default.GetBytes(original);
            byte[] kb = System.Text.Encoding.Default.GetBytes(key);
            return Convert.ToBase64String(Encrypt(buff,kb));
        }
        /// <summary>
        /// 使用给定密钥字符串解密string
        /// </summary>
        /// <param name="original">密文</param>
        /// <param name="key">密钥</param>
        /// <returns>明文</returns>
        public static string Decrypt(string original, string key)
        {
            return Decrypt(original,key,System.Text.Encoding.Default);
        }

        /// <summary>
        /// 使用给定密钥字符串解密string,返回指定编码方式明文
        /// </summary>
        /// <param name="encrypted">密文</param>
        /// <param name="key">密钥</param>
        /// <param name="encoding">字符编码方案</param>
        /// <returns>明文</returns>
        public static string Decrypt(string encrypted, string key,Encoding encoding)
        {
            byte[] buff = Convert.FromBase64String(encrypted);
            byte[] kb = System.Text.Encoding.Default.GetBytes(key);
            return encoding.GetString(Decrypt(buff,kb));
        }
        #endregion

        #region 使用 缺省密钥字符串 加密/解密/byte[]
        /// <summary>
        /// 使用缺省密钥字符串解密byte[]
        /// </summary>
        /// <param name="encrypted">密文</param>
        /// <param name="key">密钥</param>
        /// <returns>明文</returns>
        public static byte[] Decrypt(byte[] encrypted)
        {
            byte[] key = System.Text.Encoding.Default.GetBytes("MATICSOFT");
            return Decrypt(encrypted,key);
        }
        /// <summary>
        /// 使用缺省密钥字符串加密
        /// </summary>
        /// <param name="original">原始数据</param>
        /// <param name="key">密钥</param>
        /// <returns>密文</returns>
        public static byte[] Encrypt(byte[] original)
        {
            byte[] key = System.Text.Encoding.Default.GetBytes("MATICSOFT");
            return Encrypt(original,key);
        }
        #endregion

        #region  使用 给定密钥 加密/解密/byte[]

        /// <summary>
        /// 生成MD5摘要
        /// </summary>
        /// <param name="original">数据源</param>
        /// <returns>摘要</returns>
        public static byte[] MakeMD5(byte[] original)
        {
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            byte[] keyhash = hashmd5.ComputeHash(original);
            hashmd5 = null;
            return keyhash;
        }

        /// <summary>
        /// 使用给定密钥加密
        /// </summary>
        /// <param name="original">明文</param>
        /// <param name="key">密钥</param>
        /// <returns>密文</returns>
        public static byte[] Encrypt(byte[] original, byte[] key)
        {
            TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
            des.Key =  MakeMD5(key);
            des.Mode = CipherMode.ECB;  

            return des.CreateEncryptor().TransformFinalBlock(original, , original.Length);
        }  

        /// <summary>
        /// 使用给定密钥解密数据
        /// </summary>
        /// <param name="encrypted">密文</param>
        /// <param name="key">密钥</param>
        /// <returns>明文</returns>
        public static byte[] Decrypt(byte[] encrypted, byte[] key)
        {
            TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
            des.Key =  MakeMD5(key);
            des.Mode = CipherMode.ECB;  

            return des.CreateDecryptor().TransformFinalBlock(encrypted, , encrypted.Length);
        }  

        #endregion

    }
}

DEncrypt

using System;
using System.Security.Cryptography;
using System.Text;
namespace Maticsoft.Common.DEncrypt
{
    /// <summary>
    /// DES加密/解密类。
    /// LiTianPing
    /// </summary>
    public class DESEncrypt
    {
        public DESEncrypt()
        {
        }

        #region ========加密======== 

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="Text"></param>
        /// <returns></returns>
        public static string Encrypt(string Text)
        {
            return Encrypt(Text,"MATICSOFT");
        }
        /// <summary>
        /// 加密数据
        /// </summary>
        /// <param name="Text"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        public static string Encrypt(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(, ));
            des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
            System.IO.MemoryStream ms=new System.IO.MemoryStream();
            CryptoStream cs=new CryptoStream(ms,des.CreateEncryptor(),CryptoStreamMode.Write);
            cs.Write(inputByteArray,,inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret=new StringBuilder();
            foreach( byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}",b);
            }
            return ret.ToString();
        } 

        #endregion

        #region ========解密======== 

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="Text"></param>
        /// <returns></returns>
        public static string Decrypt(string Text)
        {
            return Decrypt(Text,"MATICSOFT");
        }
        /// <summary>
        /// 解密数据
        /// </summary>
        /// <param name="Text"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        public static string Decrypt(string Text,string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            int len;
            len=Text.Length/;
            byte[] inputByteArray = new byte[len];
            int x,i;
            for(x=;x<len;x++)
            {
                i = Convert.ToInt32(Text.Substring(x * , ), );
                inputByteArray[x]=(byte)i;
            }
            des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
            des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
            System.IO.MemoryStream ms=new System.IO.MemoryStream();
            CryptoStream cs=new CryptoStream(ms,des.CreateDecryptor(),CryptoStreamMode.Write);
            cs.Write(inputByteArray,,inputByteArray.Length);
            cs.FlushFinalBlock();
            return Encoding.Default.GetString(ms.ToArray());
        } 

        #endregion 

    }
}

DESEncrypt

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

namespace Common
{
    public class Encrypt
    {
        public Encrypt()
        {
        }

        //密钥
        private static byte[] arrDESKey = new byte[] {, , , , , , , };
        private static byte[] arrDESIV = new byte[] {, , , , , , , };

        /// <summary>
        /// 加密。
        /// </summary>
        /// <param name="m_Need_Encode_String"></param>
        /// <returns></returns>
        public static string Encode(string m_Need_Encode_String)
        {
            if (m_Need_Encode_String == null)
            {
                throw new Exception("Error: \n源字符串为空！！");
            }
            DESCryptoServiceProvider objDES = new DESCryptoServiceProvider();
            MemoryStream objMemoryStream = new MemoryStream();
            CryptoStream objCryptoStream = new CryptoStream(objMemoryStream, objDES.CreateEncryptor(arrDESKey, arrDESIV),
                CryptoStreamMode.Write);
            StreamWriter objStreamWriter = new StreamWriter(objCryptoStream);
            objStreamWriter.Write(m_Need_Encode_String);
            objStreamWriter.Flush();
            objCryptoStream.FlushFinalBlock();
            objMemoryStream.Flush();
            return Convert.ToBase64String(objMemoryStream.GetBuffer(), , (int) objMemoryStream.Length);
        }

        /// <summary>
        /// 解密。
        /// </summary>
        /// <param name="m_Need_Encode_String"></param>
        /// <returns></returns>
        public static string Decode(string m_Need_Encode_String)
        {
            if (m_Need_Encode_String == null)
            {
                throw new Exception("Error: \n源字符串为空！！");
            }
            DESCryptoServiceProvider objDES = new DESCryptoServiceProvider();
            byte[] arrInput = Convert.FromBase64String(m_Need_Encode_String);
            MemoryStream objMemoryStream = new MemoryStream(arrInput);
            CryptoStream objCryptoStream = new CryptoStream(objMemoryStream, objDES.CreateDecryptor(arrDESKey, arrDESIV),
                CryptoStreamMode.Read);
            StreamReader objStreamReader = new StreamReader(objCryptoStream);
            return objStreamReader.ReadToEnd();
        }

        /// <summary>
        /// md5
        /// </summary>
        /// <param name="encypStr"></param>
        /// <returns></returns>
        public static string Md5(string encypStr)
        {
            string retStr;
            MD5CryptoServiceProvider m5 = new MD5CryptoServiceProvider();
            byte[] inputBye;
            byte[] outputBye;
            inputBye = System.Text.Encoding.ASCII.GetBytes(encypStr);
            outputBye = m5.ComputeHash(inputBye);
            retStr = Convert.ToBase64String(outputBye);
            return (retStr);
        }

        #region TripleDES加密

        /// <summary>
        /// TripleDES加密
        /// </summary>
        public static string TripleDESEncrypting(string strSource)
        {
            try
            {
                byte[] bytIn = Encoding.Default.GetBytes(strSource);
                byte[] key =
                {
                    , , , , , , , , , , , , , , , , , , , , ,
                    , ,
                }; //定义密钥
                byte[] IV = {, , , , , , , }; //定义偏移量
                TripleDESCryptoServiceProvider TripleDES = new TripleDESCryptoServiceProvider();
                TripleDES.IV = IV;
                TripleDES.Key = key;
                ICryptoTransform encrypto = TripleDES.CreateEncryptor();
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
                cs.Write(bytIn, , bytIn.Length);
                cs.FlushFinalBlock();
                byte[] bytOut = ms.ToArray();
                return System.Convert.ToBase64String(bytOut);
            }
            catch (Exception ex)
            {
                throw new Exception("加密时候出现错误!错误提示:\n" + ex.Message);
            }
        }

        #endregion

        #region TripleDES解密

        /// <summary>
        /// TripleDES解密
        /// </summary>
        public static string TripleDESDecrypting(string Source)
        {
            try
            {
                byte[] bytIn = System.Convert.FromBase64String(Source);
                byte[] key =
                {
                    , , , , , , , , , , , , , , , , , , , , ,
                    , ,
                }; //定义密钥
                byte[] IV = {, , , , , , , }; //定义偏移量
                TripleDESCryptoServiceProvider TripleDES = new TripleDESCryptoServiceProvider();
                TripleDES.IV = IV;
                TripleDES.Key = key;
                ICryptoTransform encrypto = TripleDES.CreateDecryptor();
                System.IO.MemoryStream ms = new System.IO.MemoryStream(bytIn, , bytIn.Length);
                CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
                StreamReader strd = new StreamReader(cs, Encoding.Default);
                return strd.ReadToEnd();
            }
            catch (Exception ex)
            {
                throw new Exception("解密时候出现错误!错误提示:\n" + ex.Message);
            }
        }

        #endregion
    }
}

Encrypt

using System;
using System.Text;
using System.Security.Cryptography;
namespace Maticsoft.Common.DEncrypt
{
    /// <summary>
    /// 得到随机安全码（哈希加密）。
    /// </summary>
    public class HashEncode
    {
        public HashEncode()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }
        /// <summary>
        /// 得到随机哈希加密字符串
        /// </summary>
        /// <returns></returns>
        public static string GetSecurity()
        {
            string Security = HashEncoding(GetRandomValue());
            return Security;
        }
        /// <summary>
        /// 得到一个随机数值
        /// </summary>
        /// <returns></returns>
        public static string GetRandomValue()
        {
            Random Seed = new Random();
            string RandomVaule = Seed.Next(, int.MaxValue).ToString();
            return RandomVaule;
        }
        /// <summary>
        /// 哈希加密一个字符串
        /// </summary>
        /// <param name="Security"></param>
        /// <returns></returns>
        public static string HashEncoding(string Security)
        {
            byte[] Value;
            UnicodeEncoding Code = new UnicodeEncoding();
            byte[] Message = Code.GetBytes(Security);
            SHA512Managed Arithmetic = new SHA512Managed();
            Value = Arithmetic.ComputeHash(Message);
            Security = "";
            foreach(byte o in Value)
            {
                Security += (int) o + "O";
            }
            return Security;
        }
    }
}

HashEncode

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

namespace Commons
{
    /// <summary>
    /// MD5各种长度加密字符、验证MD5等操作辅助类
    /// </summary>
    public class MD5Util
    {
        public MD5Util()
        {
        }

        /// <summary>
        /// 获得32位的MD5加密
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string GetMD5_32(string input)
        {
            System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
            byte[] data = md5.ComputeHash(System.Text.Encoding.Default.GetBytes(input));
            StringBuilder sb = new StringBuilder();
            for (int i = ; i < data.Length; i++)
            {
                sb.Append(data[i].ToString("x2"));
            }
            return sb.ToString();
        }

        /// <summary>
        /// 获得16位的MD5加密
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string GetMD5_16(string input)
        {
            return GetMD5_32(input).Substring(, );
        }

        /// <summary>
        /// 获得8位的MD5加密
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string GetMD5_8(string input)
        {
            return GetMD5_32(input).Substring(, );
        }

        /// <summary>
        /// 获得4位的MD5加密
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string GetMD5_4(string input)
        {
            return GetMD5_32(input).Substring(, );
        }

        /// <summary>
        /// 添加MD5的前缀，便于检查有无篡改
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string AddMD5Profix(string input)
        {
            return GetMD5_4(input) + input;
        }

        /// <summary>
        /// 移除MD5的前缀
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string RemoveMD5Profix(string input)
        {
            return input.Substring();
        }

        /// <summary>
        /// 验证MD5前缀处理的字符串有无被篡改
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static bool ValidateValue(string input)
        {
            bool res = false;
            if (input.Length >= )
            {
                string tmp = input.Substring();
                if (input.Substring(, ) == GetMD5_4(tmp))
                {
                    res = true;
                }
            }
            return res;
        }

        #region MD5签名验证
        /// <summary>
        /// 对给定文件路径的文件加上标签
        /// </summary>
        /// <param name="path">要加密的文件的路径</param>
        /// <returns>标签的值</returns>
        public static bool AddMD5(string path)
        {
            bool IsNeed = true;

            if (CheckMD5(path))                                  //已进行MD5处理
                IsNeed = false;

            try
            {
                FileStream fsread = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
                byte[] md5File = new byte[fsread.Length];
                fsread.Read(md5File, , (int)fsread.Length);                               // 将文件流读取到Buffer中
                fsread.Close();

                if (IsNeed)
                {
                    string result = MD5Buffer(md5File, , md5File.Length);             // 对Buffer中的字节内容算MD5
                    byte[] md5 = System.Text.Encoding.ASCII.GetBytes(result);       // 将字符串转换成字节数组以便写人到文件中
                    FileStream fsWrite = new FileStream(path, FileMode.Open, FileAccess.ReadWrite);
                    fsWrite.Write(md5File, , md5File.Length);                               // 将文件，MD5值 重新写入到文件中。
                    fsWrite.Write(md5, , md5.Length);
                    fsWrite.Close();
                }
                else
                {
                    FileStream fsWrite = new FileStream(path, FileMode.Open, FileAccess.ReadWrite);
                    fsWrite.Write(md5File, , md5File.Length);
                    fsWrite.Close();
                }
            }
            catch
            {
                return false;
            }

            return true;
        }

        /// <summary>
        /// 对给定路径的文件进行验证
        /// </summary>
        /// <param name="path"></param>
        /// <returns>是否加了标签或是否标签值与内容值一致</returns>
        public static bool CheckMD5(string path)
        {
            try
            {
                FileStream get_file = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
                byte[] md5File = new byte[get_file.Length];                                      // 读入文件
                get_file.Read(md5File, , (int)get_file.Length);
                get_file.Close();

                string result = MD5Buffer(md5File, , md5File.Length - );             // 对文件除最后32位以外的字节计算MD5，这个32是因为标签位为32位。
                string md5 = System.Text.Encoding.ASCII.GetString(md5File, md5File.Length - , );   //读取文件最后32位，其中保存的就是MD5值
                return result == md5;
            }
            catch
            {
                return false;
            }
        }

        /// <summary>
        /// 计算文件的MD5值
        /// </summary>
        /// <param name="MD5File">MD5签名文件字符数组</param>
        /// <param name="index">计算起始位置</param>
        /// <param name="count">计算终止位置</param>
        /// <returns>计算结果</returns>
        private static string MD5Buffer(byte[] MD5File, int index, int count)
        {
            System.Security.Cryptography.MD5CryptoServiceProvider get_md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] hash_byte = get_md5.ComputeHash(MD5File, index, count);
            string result = System.BitConverter.ToString(hash_byte);

            result = result.Replace("-", "");
            return result;
        }
        #endregion

        private void Test()
        {
            string o = "i love u";
            o = AddMD5Profix(o);
            //o += " ";
            Console.WriteLine(o);
            Console.WriteLine(ValidateValue(o));

            o = RemoveMD5Profix(o);
            Console.WriteLine(o);

        }
    }
}

MD5Util

using System;
using System.Text;
using System.Security.Cryptography;
using System.IO;
using System.Text.RegularExpressions;
using System.Collections;
using Core.Common;

namespace Common
{
    /// <summary>
    /// MySecurity(安全类) 的摘要说明。
    /// </summary>
    public class MySecurity
    {
        /// <summary>
        /// 初始化安全类
        /// </summary>
        public MySecurity()
        {
            ///默认密码
            key = "";
        }
        private string key; //默认密钥

        private byte[] sKey;
        private byte[] sIV;

        #region 加密字符串
        /// <summary>
        /// 加密字符串
        /// </summary>
        /// <param name="inputStr">输入字符串</param>
        /// <param name="keyStr">密码，可以为“”</param>
        /// <returns>输出加密后字符串</returns>
        public static string SEncryptString(string inputStr, string keyStr)
        {
            MySecurity ws = new MySecurity();
            return ws.EncryptString(inputStr, keyStr);
        }
        /// <summary>
        /// 加密字符串
        /// </summary>
        /// <param name="inputStr">输入字符串</param>
        /// <param name="keyStr">密码，可以为“”</param>
        /// <returns>输出加密后字符串</returns>
        public string EncryptString(string inputStr, string keyStr)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            if (keyStr == "")
                keyStr = key;
            byte[] inputByteArray = Encoding.Default.GetBytes(inputStr);
            byte[] keyByteArray = Encoding.Default.GetBytes(keyStr);
            SHA1 ha = new SHA1Managed();
            byte[] hb = ha.ComputeHash(keyByteArray);
            sKey = new byte[];
            sIV = new byte[];
            for (int i = ; i < ; i++)
                sKey[i] = hb[i];
            for (int i = ; i < ; i++)
                sIV[i - ] = hb[i];
            des.Key = sKey;
            des.IV = sIV;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, , inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            cs.Close();
            ms.Close();
            return ret.ToString();
        }
        #endregion

        #region 加密字符串 密钥为系统默认 0123456789
        /// <summary>
        /// 加密字符串 密钥为系统默认
        /// </summary>
        /// <param name="inputStr">输入字符串</param>
        /// <returns>输出加密后字符串</returns>
        static public string SEncryptString(string inputStr)
        {
            MySecurity ws = new MySecurity();
            return ws.EncryptString(inputStr, "");
        }
        #endregion

        #region 加密文件
        /// <summary>
        /// 加密文件
        /// </summary>
        /// <param name="filePath">输入文件路径</param>
        /// <param name="savePath">加密后输出文件路径</param>
        /// <param name="keyStr">密码，可以为“”</param>
        /// <returns></returns>
        public bool EncryptFile(string filePath, string savePath, string keyStr)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            if (keyStr == "")
                keyStr = key;
            FileStream fs = File.OpenRead(filePath);
            byte[] inputByteArray = new byte[fs.Length];
            fs.Read(inputByteArray, , (int)fs.Length);
            fs.Close();
            byte[] keyByteArray = Encoding.Default.GetBytes(keyStr);
            SHA1 ha = new SHA1Managed();
            byte[] hb = ha.ComputeHash(keyByteArray);
            sKey = new byte[];
            sIV = new byte[];
            for (int i = ; i < ; i++)
                sKey[i] = hb[i];
            for (int i = ; i < ; i++)
                sIV[i - ] = hb[i];
            des.Key = sKey;
            des.IV = sIV;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, , inputByteArray.Length);
            cs.FlushFinalBlock();
            fs = File.OpenWrite(savePath);
            foreach (byte b in ms.ToArray())
            {
                fs.WriteByte(b);
            }
            fs.Close();
            cs.Close();
            ms.Close();
            return true;
        }
        #endregion

        #region 解密字符串
        /// <summary>
        /// 解密字符串
        /// </summary>
        /// <param name="inputStr">要解密的字符串</param>
        /// <param name="keyStr">密钥</param>
        /// <returns>解密后的结果</returns>
        static public string SDecryptString(string inputStr, string keyStr)
        {
            MySecurity ws = new MySecurity();
            return ws.DecryptString(inputStr, keyStr);
        }
        /// <summary>
        ///  解密字符串 密钥为系统默认
        /// </summary>
        /// <param name="inputStr">要解密的字符串</param>
        /// <returns>解密后的结果</returns>
        static public string SDecryptString(string inputStr)
        {
            MySecurity ws = new MySecurity();
            return ws.DecryptString(inputStr, "");
        }
        /// <summary>
        /// 解密字符串
        /// </summary>
        /// <param name="inputStr">要解密的字符串</param>
        /// <param name="keyStr">密钥</param>
        /// <returns>解密后的结果</returns>
        public string DecryptString(string inputStr, string keyStr)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            if (keyStr == "")
                keyStr = key;
            byte[] inputByteArray = new byte[inputStr.Length / ];
            for (int x = ; x < inputStr.Length / ; x++)
            {
                int i = (Convert.ToInt32(inputStr.Substring(x * , ), ));
                inputByteArray[x] = (byte)i;
            }
            byte[] keyByteArray = Encoding.Default.GetBytes(keyStr);
            SHA1 ha = new SHA1Managed();
            byte[] hb = ha.ComputeHash(keyByteArray);
            sKey = new byte[];
            sIV = new byte[];
            for (int i = ; i < ; i++)
                sKey[i] = hb[i];
            for (int i = ; i < ; i++)
                sIV[i - ] = hb[i];
            des.Key = sKey;
            des.IV = sIV;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, , inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }
        #endregion

        #region 解密文件
        /// <summary>
        /// 解密文件
        /// </summary>
        /// <param name="filePath">输入文件路径</param>
        /// <param name="savePath">解密后输出文件路径</param>
        /// <param name="keyStr">密码，可以为“”</param>
        /// <returns></returns>
        public bool DecryptFile(string filePath, string savePath, string keyStr)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            if (keyStr == "")
                keyStr = key;
            FileStream fs = File.OpenRead(filePath);
            byte[] inputByteArray = new byte[fs.Length];
            fs.Read(inputByteArray, , (int)fs.Length);
            fs.Close();
            byte[] keyByteArray = Encoding.Default.GetBytes(keyStr);
            SHA1 ha = new SHA1Managed();
            byte[] hb = ha.ComputeHash(keyByteArray);
            sKey = new byte[];
            sIV = new byte[];
            for (int i = ; i < ; i++)
                sKey[i] = hb[i];
            for (int i = ; i < ; i++)
                sIV[i - ] = hb[i];
            des.Key = sKey;
            des.IV = sIV;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, , inputByteArray.Length);
            cs.FlushFinalBlock();
            fs = File.OpenWrite(savePath);
            foreach (byte b in ms.ToArray())
            {
                fs.WriteByte(b);
            }
            fs.Close();
            cs.Close();
            ms.Close();
            return true;
        }
        #endregion

        #region Base64加密
        /// <summary>
        /// Base64加密
        /// </summary>
        /// <param name="text">要加密的字符串</param>
        /// <returns></returns>
        public static string EncodeBase64(string text)
        {
            //如果字符串为空，则返回
            if (StringHelper.IsNullOrEmpty<string>(text))
            {
                return "";
            }

            try
            {
                char[] Base64Code = new char[]{'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T',
                                            'U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n',
                                            'o','p','q','r','s','t','u','v','w','x','y','z','','','','','','','','',
                                            '','','+','/','='};
                byte empty = (byte);
                ArrayList byteMessage = new ArrayList(Encoding.Default.GetBytes(text));
                StringBuilder outmessage;
                int messageLen = byteMessage.Count;
                int page = messageLen / ;
                int use = ;
                if ((use = messageLen % ) > )
                {
                    for (int i = ; i <  - use; i++)
                        byteMessage.Add(empty);
                    page++;
                }
                outmessage = new System.Text.StringBuilder(page * );
                for (int i = ; i < page; i++)
                {
                    byte[] instr = new byte[];
                    instr[] = (byte)byteMessage[i * ];
                    instr[] = (byte)byteMessage[i *  + ];
                    instr[] = (byte)byteMessage[i *  + ];
                    int[] outstr = new int[];
                    outstr[] = instr[] >> ;
                    outstr[] = ((instr[] & 0x03) << ) ^ (instr[] >> );
                    if (!instr[].Equals(empty))
                        outstr[] = ((instr[] & 0x0f) << ) ^ (instr[] >> );
                    else
                        outstr[] = ;
                    if (!instr[].Equals(empty))
                        outstr[] = (instr[] & 0x3f);
                    else
                        outstr[] = ;
                    outmessage.Append(Base64Code[outstr[]]);
                    outmessage.Append(Base64Code[outstr[]]);
                    outmessage.Append(Base64Code[outstr[]]);
                    outmessage.Append(Base64Code[outstr[]]);
                }
                return outmessage.ToString();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
        #endregion

        #region Base64解密
        /// <summary>
        /// Base64解密
        /// </summary>
        /// <param name="text">要解密的字符串</param>
        public static string DecodeBase64(string text)
        {
            //如果字符串为空，则返回
            if (StringHelper.IsNullOrEmpty<string>(text))
            {
                return "";
            }

            //将空格替换为加号
            text = text.Replace(" ", "+");

            try
            {
                if ((text.Length % ) != )
                {
                    return "包含不正确的BASE64编码";
                }
                if (!Regex.IsMatch(text, "^[A-Z0-9/+=]*$", RegexOptions.IgnoreCase))
                {
                    return "包含不正确的BASE64编码";
                }
                string Base64Code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
                int page = text.Length / ;
                ArrayList outMessage = new ArrayList(page * );
                char[] message = text.ToCharArray();
                for (int i = ; i < page; i++)
                {
                    byte[] instr = new byte[];
                    instr[] = (byte)Base64Code.IndexOf(message[i * ]);
                    instr[] = (byte)Base64Code.IndexOf(message[i *  + ]);
                    instr[] = (byte)Base64Code.IndexOf(message[i *  + ]);
                    instr[] = (byte)Base64Code.IndexOf(message[i *  + ]);
                    byte[] outstr = new byte[];
                    outstr[] = (byte)((instr[] << ) ^ ((instr[] & 0x30) >> ));
                    if (instr[] != )
                    {
                        outstr[] = (byte)((instr[] << ) ^ ((instr[] & 0x3c) >> ));
                    }
                    else
                    {
                        outstr[] = ;
                    }
                    if (instr[] != )
                    {
                        outstr[] = (byte)((instr[] << ) ^ instr[]);
                    }
                    else
                    {
                        outstr[] = ;
                    }
                    outMessage.Add(outstr[]);
                    if (outstr[] != )
                        outMessage.Add(outstr[]);
                    if (outstr[] != )
                        outMessage.Add(outstr[]);
                }
                byte[] outbyte = (byte[])outMessage.ToArray(Type.GetType("System.Byte"));
                return Encoding.Default.GetString(outbyte);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
        #endregion
    }
}

MySecurity

using System;
using System.Text;
using System.Security.Cryptography;
namespace Maticsoft.Common.DEncrypt
{
    /// <summary>
    /// RSA加密解密及RSA签名和验证
    /// </summary>
    public class RSACryption
    {
        public RSACryption()
        {
        } 

        #region RSA 加密解密 

        #region RSA 的密钥产生 

        /// <summary>
        /// RSA 的密钥产生 产生私钥 和公钥
        /// </summary>
        /// <param name="xmlKeys"></param>
        /// <param name="xmlPublicKey"></param>
        public void RSAKey(out string xmlKeys,out string xmlPublicKey)
        {
                System.Security.Cryptography.RSACryptoServiceProvider rsa=new RSACryptoServiceProvider();
                xmlKeys=rsa.ToXmlString(true);
                xmlPublicKey = rsa.ToXmlString(false);
        }
        #endregion 

        #region RSA的加密函数
        //##############################################################################
        //RSA 方式加密
        //说明KEY必须是XML的行式,返回的是字符串
        //在有一点需要说明！！该加密方式有 长度 限制的！！
        //############################################################################## 

        //RSA的加密函数  string
        public string RSAEncrypt(string xmlPublicKey,string m_strEncryptString )
        { 

            byte[] PlainTextBArray;
            byte[] CypherTextBArray;
            string Result;
            RSACryptoServiceProvider rsa=new RSACryptoServiceProvider();
            rsa.FromXmlString(xmlPublicKey);
            PlainTextBArray = (new UnicodeEncoding()).GetBytes(m_strEncryptString);
            CypherTextBArray = rsa.Encrypt(PlainTextBArray, false);
            Result=Convert.ToBase64String(CypherTextBArray);
            return Result; 

        }
        //RSA的加密函数 byte[]
        public string RSAEncrypt(string xmlPublicKey,byte[] EncryptString )
        { 

            byte[] CypherTextBArray;
            string Result;
            RSACryptoServiceProvider rsa=new RSACryptoServiceProvider();
            rsa.FromXmlString(xmlPublicKey);
            CypherTextBArray = rsa.Encrypt(EncryptString, false);
            Result=Convert.ToBase64String(CypherTextBArray);
            return Result; 

        }
        #endregion 

        #region RSA的解密函数
        //RSA的解密函数  string
        public string RSADecrypt(string xmlPrivateKey, string m_strDecryptString )
        {
            byte[] PlainTextBArray;
            byte[] DypherTextBArray;
            string Result;
            System.Security.Cryptography.RSACryptoServiceProvider rsa=new RSACryptoServiceProvider();
            rsa.FromXmlString(xmlPrivateKey);
            PlainTextBArray =Convert.FromBase64String(m_strDecryptString);
            DypherTextBArray=rsa.Decrypt(PlainTextBArray, false);
            Result=(new UnicodeEncoding()).GetString(DypherTextBArray);
            return Result; 

        } 

        //RSA的解密函数  byte
        public string RSADecrypt(string xmlPrivateKey, byte[] DecryptString )
        {
            byte[] DypherTextBArray;
            string Result;
            System.Security.Cryptography.RSACryptoServiceProvider rsa=new RSACryptoServiceProvider();
            rsa.FromXmlString(xmlPrivateKey);
            DypherTextBArray=rsa.Decrypt(DecryptString, false);
            Result=(new UnicodeEncoding()).GetString(DypherTextBArray);
            return Result; 

        }
        #endregion 

        #endregion 

        #region RSA数字签名 

        #region 获取Hash描述表
        //获取Hash描述表
        public bool GetHash(string m_strSource, ref byte[] HashData)
        {
            //从字符串中取得Hash描述
            byte[] Buffer;
            System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5");
            Buffer = System.Text.Encoding.GetEncoding("GB2312").GetBytes(m_strSource);
            HashData = MD5.ComputeHash(Buffer); 

            return true;
        } 

        //获取Hash描述表
        public bool GetHash(string m_strSource, ref string strHashData)
        { 

            //从字符串中取得Hash描述
            byte[] Buffer;
            byte[] HashData;
            System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5");
            Buffer = System.Text.Encoding.GetEncoding("GB2312").GetBytes(m_strSource);
            HashData = MD5.ComputeHash(Buffer); 

            strHashData = Convert.ToBase64String(HashData);
            return true; 

        } 

        //获取Hash描述表
        public bool GetHash(System.IO.FileStream objFile, ref byte[] HashData)
        { 

            //从文件中取得Hash描述
            System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5");
            HashData = MD5.ComputeHash(objFile);
            objFile.Close(); 

            return true; 

        } 

        //获取Hash描述表
        public bool GetHash(System.IO.FileStream objFile, ref string strHashData)
        { 

            //从文件中取得Hash描述
            byte[] HashData;
            System.Security.Cryptography.HashAlgorithm MD5 = System.Security.Cryptography.HashAlgorithm.Create("MD5");
            HashData = MD5.ComputeHash(objFile);
            objFile.Close(); 

            strHashData = Convert.ToBase64String(HashData); 

            return true; 

        }
        #endregion 

        #region RSA签名
        //RSA签名
        public bool SignatureFormatter(string p_strKeyPrivate, byte[] HashbyteSignature, ref byte[] EncryptedSignatureData)
        { 

                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPrivate);
                System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA);
                //设置签名的算法为MD5
                RSAFormatter.SetHashAlgorithm("MD5");
                //执行签名
                EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); 

                return true; 

        } 

        //RSA签名
        public bool SignatureFormatter(string p_strKeyPrivate, byte[] HashbyteSignature, ref string m_strEncryptedSignatureData)
        { 

                byte[] EncryptedSignatureData; 

                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPrivate);
                System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA);
                //设置签名的算法为MD5
                RSAFormatter.SetHashAlgorithm("MD5");
                //执行签名
                EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); 

                m_strEncryptedSignatureData = Convert.ToBase64String(EncryptedSignatureData); 

                return true; 

        } 

        //RSA签名
        public bool SignatureFormatter(string p_strKeyPrivate, string m_strHashbyteSignature, ref byte[] EncryptedSignatureData)
        { 

                byte[] HashbyteSignature; 

                HashbyteSignature = Convert.FromBase64String(m_strHashbyteSignature);
                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPrivate);
                System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA);
                //设置签名的算法为MD5
                RSAFormatter.SetHashAlgorithm("MD5");
                //执行签名
                EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); 

                return true; 

        } 

        //RSA签名
        public bool SignatureFormatter(string p_strKeyPrivate, string m_strHashbyteSignature, ref string m_strEncryptedSignatureData)
        { 

                byte[] HashbyteSignature;
                byte[] EncryptedSignatureData; 

                HashbyteSignature = Convert.FromBase64String(m_strHashbyteSignature);
                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPrivate);
                System.Security.Cryptography.RSAPKCS1SignatureFormatter RSAFormatter = new System.Security.Cryptography.RSAPKCS1SignatureFormatter(RSA);
                //设置签名的算法为MD5
                RSAFormatter.SetHashAlgorithm("MD5");
                //执行签名
                EncryptedSignatureData = RSAFormatter.CreateSignature(HashbyteSignature); 

                m_strEncryptedSignatureData = Convert.ToBase64String(EncryptedSignatureData); 

                return true; 

        }
        #endregion 

        #region RSA 签名验证 

        public bool SignatureDeformatter(string p_strKeyPublic, byte[] HashbyteDeformatter, byte[] DeformatterData)
        { 

                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPublic);
                System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA);
                //指定解密的时候HASH算法为MD5
                RSADeformatter.SetHashAlgorithm("MD5"); 

                if(RSADeformatter.VerifySignature(HashbyteDeformatter,DeformatterData))
                {
                    return true;
                }
                else
                {
                    return false;
                } 

        } 

        public bool SignatureDeformatter(string p_strKeyPublic, string p_strHashbyteDeformatter, byte[] DeformatterData)
        { 

                byte[] HashbyteDeformatter; 

                HashbyteDeformatter = Convert.FromBase64String(p_strHashbyteDeformatter); 

                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPublic);
                System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA);
                //指定解密的时候HASH算法为MD5
                RSADeformatter.SetHashAlgorithm("MD5"); 

                if(RSADeformatter.VerifySignature(HashbyteDeformatter,DeformatterData))
                {
                    return true;
                }
                else
                {
                    return false;
                } 

        } 

        public bool SignatureDeformatter(string p_strKeyPublic, byte[] HashbyteDeformatter, string p_strDeformatterData)
        { 

                byte[] DeformatterData; 

                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPublic);
                System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA);
                //指定解密的时候HASH算法为MD5
                RSADeformatter.SetHashAlgorithm("MD5"); 

                DeformatterData =Convert.FromBase64String(p_strDeformatterData); 

                if(RSADeformatter.VerifySignature(HashbyteDeformatter,DeformatterData))
                {
                    return true;
                }
                else
                {
                    return false;
                } 

        } 

        public bool SignatureDeformatter(string p_strKeyPublic, string p_strHashbyteDeformatter, string p_strDeformatterData)
        { 

                byte[] DeformatterData;
                byte[] HashbyteDeformatter; 

                HashbyteDeformatter = Convert.FromBase64String(p_strHashbyteDeformatter);
                System.Security.Cryptography.RSACryptoServiceProvider RSA = new System.Security.Cryptography.RSACryptoServiceProvider(); 

                RSA.FromXmlString(p_strKeyPublic);
                System.Security.Cryptography.RSAPKCS1SignatureDeformatter RSADeformatter = new System.Security.Cryptography.RSAPKCS1SignatureDeformatter(RSA);
                //指定解密的时候HASH算法为MD5
                RSADeformatter.SetHashAlgorithm("MD5"); 

                DeformatterData =Convert.FromBase64String(p_strDeformatterData); 

                if(RSADeformatter.VerifySignature(HashbyteDeformatter,DeformatterData))
                {
                    return true;
                }
                else
                {
                    return false;
                } 

        } 

        #endregion 

        #endregion 

    }
} 

RSACryption

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

namespace Core.Common
{
    /// <summary>
    /// 非对称加密验证辅助类
    /// </summary>
    public class RSASecurityHelper
    {
        /// <summary>
        /// 对注册信息数据采用非对称加密的方式加密
        /// </summary>
        /// <param name="originalString">未加密的文本，如机器码</param>
        /// <param name="encrytedString">加密后的文本，如注册序列号</param>
        /// <returns>如果验证成功返回True，否则为False</returns>
        public static bool Validate(string originalString, string encrytedString)
        {
            bool bPassed = false;
            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
            {
                try
                {
                    rsa.FromXmlString(UIConstants.PublicKey); //公钥
                    RSAPKCS1SignatureDeformatter formatter = new RSAPKCS1SignatureDeformatter(rsa);
                    formatter.SetHashAlgorithm("SHA1");

                    byte[] key = Convert.FromBase64String(encrytedString); //验证
                    SHA1Managed sha = new SHA1Managed();
                    byte[] name = sha.ComputeHash(ASCIIEncoding.ASCII.GetBytes(originalString));
                    if (formatter.VerifySignature(name, key))
                    {
                        bPassed = true;
                    }
                }
                catch
                {
                }
            }
            return bPassed;
        }
    }
}

RSASecurityHelper

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
using System.Text.RegularExpressions;

namespace hic.Common
{
   public class SecurityHelper
    {
        /// <summary>
        /// MD5字符串加密
        /// </summary>
        /// <param name="source">待加密字符串</param>
        /// <returns></returns>
        public static string MD5(string source)
        {
            return MD5(source, true);
        }

        /// <summary>
        /// MD5字符串加密
        /// </summary>
        /// <param name="source">待加密字符串</param>
        /// <param name="ishalf">加密是16位还是32位，如果为true则是16位。</param>
        /// <returns></returns>
        public static string MD5(string source, bool ishalf)
        {
            string outputStr = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(source, "MD5").ToLower();
            if (ishalf)//16位MD5加密（取32位加密的9~25字符）
                outputStr = outputStr.Substring(, );
            return outputStr;
        }

        /// <summary>
        /// 对字符串进行Base64编码
        /// </summary>
        /// <param name="source">待编码字符串</param>
        /// <returns></returns>
        public static string EncodeBase64(string source)
        {
            UnicodeEncoding code = new UnicodeEncoding();
            byte[] bytes = code.GetBytes(source);
            return Convert.ToBase64String(bytes);
        }

        /// <summary>
        /// 对字符串进行Base64解码
        /// </summary>
        /// <param name="source">待解码字符串</param>
        /// <returns></returns>
        public static string DecodeBase64(string source)
        {
            UnicodeEncoding code = new UnicodeEncoding();
            byte[] bytes = Convert.FromBase64String(source);
            return code.GetString(bytes);
        }

        /// <summary>
        /// 检查当前IP是否是受限IP
        /// </summary>
        /// <param name="LimitedIP">受限的IP，格式如:192.168.1.110|212.235.*.*|232.*.*.*</param>
        /// <returns>返回true表示IP未受到限制</returns>
        public static bool CheckIPIsLimited(string limitedIP)
        {
            string currentIP = GetUserIP();
            if (limitedIP == null || limitedIP.Trim() == string.Empty)
                return true;
            limitedIP.Replace(".", @"\.");
            limitedIP.Replace("*", @"[^\.]{1,3}");
            Regex reg = new Regex(limitedIP, RegexOptions.Compiled);
            Match match = reg.Match(currentIP);
            return !match.Success;
        }

        /// <summary>
        /// 得到用户IP
        /// </summary>
        /// <returns></returns>
        public static string GetUserIP()
        {
            return HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"].ToString();
        }
    }
}

SecurityHelper