C#中常用加密算法

【转载：http://www.cnblogs.com/Continue/archive/2009/11/20/1606862.html】

在日常的项目开发中，很多时候都会用到加密/解密的功能，以下是我整理出来的一些常见加密/解密的算法：包括MD5加密、SHA256加密、移位加密/解密、DES加密/解密、AES加密/解密，给大家分享一下。

 

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

public class Encrypt
{
    MD5加密#region MD5加密
    /**//// <summary>
    /// MD5加密算法
    /// </summary>
    /// <param name="PassWord">待加密的字符串</param>
    /// <returns>加密后的字符串</returns>
    public static string MD5Encrypt(string Input)
    {
        byte[] b = Encoding.Default.GetBytes(Input);
        b = new MD5CryptoServiceProvider().ComputeHash(b);
        string ret = "";
        for (int i = 0; i < b.Length; i++)
            ret += b[i].ToString("x").PadLeft(2, '0');

        return ret;
    }

    /**//// <summary>
    /// MD5加密
    /// </summary>
    /// <param name="Half">加密是16位还是32位；如果为true为16位</param>
    /// <param name="Input">待加密码字符串</param>
    /// <returns>加密后的字符串</returns>
    public static string MD5Encrypt(string Input, bool Half)
    {
        string output = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(Input, "MD5").ToLower();
        if (Half)//16位MD5加密（取32位加密的9~25字符）
            output = output.Substring(8, 16);
        return output;
    }
    #endregion

    SHA256加密#region SHA256加密
    /**//// <summary>
    /// SHA256加密
    /// </summary>
    /// /// <param name="str">待加密的字符串</param>
    /// <returns>加密后的字符串</returns>
    public static string SHAEncrypt(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
    }
    #endregion

    移位加密/解密#region 移位加密/解密
    /**//// <summary>
    /// 字符串移位加密  
    /// </summary>
    /// <param name="str">待加密数据</param>
    /// <returns>加密后的数据</returns>
    public static string ShiftEncrypt(string Input)
    {
        try
        {
            string _temp = "";
            int _inttemp;
            char[] _chartemp = Input.ToCharArray();
            for (int i = 0; i < _chartemp.Length; i++)
            {
                _inttemp = _chartemp[i] + 1;
                _chartemp[i] = (char)_inttemp;
                _temp += _chartemp[i];
            }
            return _temp;
        }
        catch
        {
            return Input.ToString();
        }
    }

    /**//// <summary>
    /// 字符串移位解密
    /// </summary>
    /// <param name="str">待解密数据</param>
    /// <returns>解密成功后的数据</returns>
    public static string ShiftDecrypt(string Input)
    {
        try
        {
            string _temp = "";
            int _inttemp;
            char[] _chartemp = Input.ToCharArray();
            for (int i = 0; i < _chartemp.Length; i++)
            {
                _inttemp = _chartemp[i] - 1;
                _chartemp[i] = (char)_inttemp;
                _temp += _chartemp[i];
            }
            return _temp;
        }
        catch
        {
            return Input.ToString();
        }
    }
    #endregion

    DES加密/解密#region DES加密/解密

    /**//// <summary>
    /// DES加密
    /// </summary>
    /// <param name="Text">待加密的字符串</param>
    /// <returns>加密后的字符串</returns>
    public static string DESEncrypt(string Text)
    {
        return DESEncrypt(Text, "Continue");
    }

    /**//// <summary> 
    /// DES加密 
    /// </summary> 
    /// <param name="Text">待加密的字符串</param> 
    /// <param name="sKey">加密密钥</param> 
    /// <returns>加密后的字符串</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);
        }
        return ret.ToString();
    }

    /**//// <summary>
    /// DES解密
    /// </summary>
    /// <param name="Text">待解密的字符串</param>
    /// <returns>解密后的字符串</returns>
    public static string DESDecrypt(string Text)
    {
        return DESDecrypt(Text, "Continue");
    }

    /**//// <summary> 
    /// DES解密 
    /// </summary> 
    /// <param name="Text">待解密的字符串</param> 
    /// <param name="sKey">解密密钥</param> 
    /// <returns>解密后的字符串</returns> 
    public static string DESDecrypt(string Text, string sKey)
    {
        try
        {
            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;
            }
            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();
            return Encoding.Default.GetString(ms.ToArray());

        }
        catch
        {
            return "";
        }
    }

    #endregion

    AES加密/解密#region AES加密/解密
    //默认密钥向量
    private static byte[] Keys = { 0x41, 0x72, 0x65, 0x79, 0x6F, 0x75, 0x6D, 0x79, 0x53, 0x6E, 0x6F, 0x77, 0x6D, 0x61, 0x6E, 0x3F };

    /**//// <summary>
    /// AES加密
    /// </summary>
    /// <param name="encryptString">待加密的字符串</param>
    /// <param name="encryptKey">加密密钥</param>
    /// <returns>加密后的字符串</returns>
    public static string AESEncrypt(string encryptString, string encryptKey)
    {
        encryptKey = GetSubString(encryptKey, 0, 32, "");
        encryptKey = encryptKey.PadRight(32, ' ');

        RijndaelManaged rijndaelProvider = new RijndaelManaged();
        rijndaelProvider.Key = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 32));
        rijndaelProvider.IV = Keys;
        ICryptoTransform rijndaelEncrypt = rijndaelProvider.CreateEncryptor();

        byte[] inputData = Encoding.UTF8.GetBytes(encryptString);
        byte[] encryptedData = rijndaelEncrypt.TransformFinalBlock(inputData, 0, inputData.Length);

        return Convert.ToBase64String(encryptedData);
    }

    /**//// <summary>
    /// AES加密
    /// </summary>
    /// <param name="encryptString">待加密的字符串</param>
    /// <returns>加密后的字符串</returns>
    public static string AESEncrypt(string encryptString)
    {
        return AESEncrypt(encryptString, "Continue");
    }

    /**//// <summary>
    /// AES解密
    /// </summary>
    /// <param name="decryptString">待解密的字符串</param>
    /// <param name="decryptKey">解密密钥</param>
    /// <returns>解密后的字符串</returns>
    public static string AESDecrypt(string decryptString, string decryptKey)
    {
        try
        {
            decryptKey = GetSubString(decryptKey, 0, 32, "");
            decryptKey = decryptKey.PadRight(32, ' ');

            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, 0, inputData.Length);

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

    }

    /**//// <summary>
    /// AES解密
    /// </summary>
    /// <param name="decryptString">待解密的字符串</param>
    /// <returns>解密后的字符串</returns>
    public static string AESDecrypt(string decryptString)
    {
        return AESDecrypt(decryptString, "Continue");
    }

    /**//// <summary>
    /// 取指定长度的字符串
    /// </summary>
    /// <param name="p_SrcString">要检查的字符串</param>
    /// <param name="p_StartIndex">起始位置</param>
    /// <param name="p_Length">指定长度</param>
    /// <param name="p_TailString">用于替换的字符串</param>
    /// <returns>截取后的字符串</returns>
    private static string GetSubString(string p_SrcString, int p_StartIndex, int p_Length, string p_TailString)
    {
        string myResult = p_SrcString;

        Byte[] bComments = Encoding.UTF8.GetBytes(p_SrcString);
        foreach (char c in Encoding.UTF8.GetChars(bComments))
        {    //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 ((c > '\u0800' && c < '\u4e00') || (c > '\xAC00' && c < '\xD7A3'))
            {
                //if (System.Text.RegularExpressions.Regex.IsMatch(p_SrcString, "[\u0800-\u4e00]+") || System.Text.RegularExpressions.Regex.IsMatch(p_SrcString, "[\xAC00-\xD7A3]+"))
                //当截取的起始位置超出字段串长度时
                if (p_StartIndex >= p_SrcString.Length)
                    return "";
                else
                    return p_SrcString.Substring(p_StartIndex,
                                                   ((p_Length + p_StartIndex) > p_SrcString.Length) ? (p_SrcString.Length - p_StartIndex) : p_Length);
            }
        }

        if (p_Length >= 0)
        {
            byte[] bsSrcString = Encoding.Default.GetBytes(p_SrcString);

            //当字符串长度大于起始位置
            if (bsSrcString.Length > p_StartIndex)
            {
                int p_EndIndex = bsSrcString.Length;

                //当要截取的长度在字符串的有效长度范围内
                if (bsSrcString.Length > (p_StartIndex + p_Length))
                {
                    p_EndIndex = p_Length + p_StartIndex;
                }
                else
                {   //当不在有效范围内时,只取到字符串的结尾

                    p_Length = bsSrcString.Length - p_StartIndex;
                    p_TailString = "";
                }

                int nRealLength = p_Length;
                int[] anResultFlag = new int[p_Length];
                byte[] bsResult = null;

                int nFlag = 0;
                for (int i = p_StartIndex; i < p_EndIndex; i++)
                {
                    if (bsSrcString[i] > 127)
                    {
                        nFlag++;
                        if (nFlag == 3)
                            nFlag = 1;
                    }
                    else
                        nFlag = 0;

                    anResultFlag[i] = nFlag;
                }

                if ((bsSrcString[p_EndIndex - 1] > 127) && (anResultFlag[p_Length - 1] == 1))
                    nRealLength = p_Length + 1;

                bsResult = new byte[nRealLength];

                Array.Copy(bsSrcString, p_StartIndex, bsResult, 0, nRealLength);

                myResult = Encoding.Default.GetString(bsResult);
                myResult = myResult + p_TailString;
            }
        }

        return myResult;
    }

    #endregion
}

　　

这里是上面的源代码：点击这里下载

注：

“b[i].ToString("x").PadLeft(2, '0');”

byte转十六进制直接ToString("X2")就可以了。