谈谈数据加密的处理--提供各种算法处理

数据的加密重要性大家皆知,很多情况下需要对数据进行加密处理,但各种重要数据的加密要求不一样,有些需要时可逆的,有些是不要求可逆的,可逆的一般称之为对称加密算法,不可逆的一般可以成为非对称加密算法。如登录密码,一般较好的方式是采用不可逆的加密算法,如MD5、SHA256、哈希数值等,当然也有的采用可逆的强度好一些的加密方式,在选择加密键值的时候,变化一下也算是比较不错的选择。另外一些为了掩人耳目或者不让别人直接可以查看到,就采用其他的加密算法,如DES加密算法、AES的RijndaelManaged加密算法,或者也可以采用Base64加密,甚至我看到一个很变态的方式,就是用MD5加密的头,内容则采用Base64的方式加密,一般不知道内情的还真的不好处理。

在吉日《[走火入魔失眠夜]浅谈管理软件信息安全,用户名、密码的加密解密【附C#配套加密解密源码】》 的文章中也对加密做了一些介绍和分析,并贴出了MD5、DES的加密方式代码,吉日的文章图文并茂、哲理及诙谐例子并存,本文有感而发,做一些补充,希望园子同行共通过切磋,交流心得。

加密字符串的方式有很多,也都可以通过这样的加密文件内容,不过较好的方式可能是采用DES及AES两种方式来加密文件了,下面贴出的代码中包含了加解密文件的算法。下面具体贴出本人收藏的各种加密算法代码。

 

1、DES加密字符串及文件等

如果想可逆的算法,这种方式一般不错,只要结合动态密钥,就可以做出强度比较高的加密应用了。 

         #region DES对称加密解密

        public const string DEFAULT_ENCRYPT_KEY = "12345678";

        
/// <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 = { 0x120x340x560x780x900xAB0xCD0xEF };

            byKey 
= Encoding.UTF8.GetBytes(strEncrKey.Substring(08));
            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, 
0, 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 = { 0x120x340x560x780x900xAB0xCD0xEF };
            
byte[] inputByteArray = new Byte[strText.Length];

            byKey 
= Encoding.UTF8.GetBytes(sDecrKey.Substring(08));
            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, 
0, 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 = { 0x120x340x560x780x900xAB0xCD0xEF };

            byKey 
= Encoding.UTF8.GetBytes(strEncrKey.Substring(08));
            FileStream fin 
= new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
            FileStream fout 
= new FileStream(m_OutFilePath, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength(
0);
            
//Create variables to help with read and write. 
            byte[] bin = new byte[100]; //This is intermediate storage for the encryption. 
            long rdlen = 0//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, 0100);
                encStream.Write(bin, 
0, 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 = { 0x120x340x560x780x900xAB0xCD0xEF };

            byKey 
= Encoding.UTF8.GetBytes(sDecrKey.Substring(08));
            FileStream fin 
= new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
            FileStream fout 
= new FileStream(m_OutFilePath, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength(
0);
            
//Create variables to help with read and write. 
            byte[] bin = new byte[100]; //This is intermediate storage for the encryption. 
            long rdlen = 0//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, 0100);
                encStream.Write(bin, 
0, len);
                rdlen 
= rdlen + len;
            }
            encStream.Close();
            fout.Close();
            fin.Close();
        } 
        
#endregion

 

 

2、 对称加密算法AES RijndaelManaged加密解密

         #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 = { 0x410x720x650x790x6F0x750x6D0x79,
                                             
0x53,0x6E0x6F0x770x6D0x610x6E0x3F };

        
/// <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, 32"");
            encryptKey 
= encryptKey.PadRight(32' ');

            RijndaelManaged rijndaelProvider 
= new RijndaelManaged();
            rijndaelProvider.Key 
= Encoding.UTF8.GetBytes(encryptKey.Substring(032));
            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>
        
/// 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, 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 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, 0, 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 <= 0)
            {
                
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 = 0;
                
//字节大于127为双字节字符
                for (int i = startIndex; i < endIndex; i++)
                {
                    
if (bytesSource[i] > 127)
                    {
                        nFlag
++;
                        
if (nFlag == 3)
                        {
                            nFlag 
= 1;
                        }
                    }
                    
else
                    {
                        nFlag 
= 0;
                    }
                    anResultFlag[i] 
= nFlag;
                }
                
//最后一个字节为双字节字符的一半
                if ((bytesSource[endIndex - 1> 127&& (anResultFlag[length - 1== 1))
                {
                    length 
= length + 1;
                }

                
byte[] bsResult = new byte[length];
                Array.Copy(bytesSource, startIndex, bsResult, 
0, 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, 32"");
            decryptKey 
= decryptKey.PadRight(32' ');

            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, 32"");
            decryptKey 
= decryptKey.PadRight(32' ');

            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, 
0, bytearrayinput.Length);
                Enfr.Write(bytearrayinput, 
0, 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[1024];
                
int m_count = 0;

                
do
                {
                    m_count 
= Defr.Read(bytearrayoutput, 0, bytearrayoutput.Length);
                    frde.Write(bytearrayoutput, 
0, 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

 

 

3、  Base64加密解密算法

         #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

 

 

4、 MD5加密及验证

MD5的加密处理应用还是比较多,由于破解难度很大,基本上大型网站或者软件商,密码加密一般采用这种方式居多。

而MD5可以用来获得32、 16、8等全部部分内容加密内容,也可以获取其加密后的哈希值。

         /// <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 = 0; 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(816);
        }
        
/// <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(88);
        }
        
/// <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(84);
        }

        
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), 0, 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);
        }

 

 

5、 对文件添加MD5标签及验证

这种方式比较有趣,我也是最近才发现其中的奥妙,其实我们为了防止文件被修改,可以采用这种方式预先添加MD5码,然后在程序代码中进行验证,这样至少可以减少部分篡改的行为吧,因为只要文件有些少的修改,Md5码将会发生变化的,呵呵。

         #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, 
0, (int)fsread.Length);                               // 将文件流读取到Buffer中
                fsread.Close();

                
if (IsNeed)
                {
                    
string result = MD5Buffer(md5File, 0, 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, 
0, md5File.Length);                               // 将文件,MD5值 重新写入到文件中。
                    fsWrite.Write(md5, 0, md5.Length);
                    fsWrite.Close();
                }
                
else
                {
                    FileStream fsWrite 
= new FileStream(path, FileMode.Open, FileAccess.ReadWrite);
                    fsWrite.Write(md5File, 
0, 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, 0, (int)get_file.Length);
                get_file.Close();

                
string result = MD5Buffer(md5File, 0, md5File.Length - 32);             // 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 - 3232);   //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

 

 

6、 SHA256加密算法

         /// <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
        }

 

 

7、 MD5及Base64结合加密

这种结合方式也是比较不错的算法,至少是四不像,一般分析比较困难,比较有迷惑性,就是挂羊头,卖狗肉的行为,其实Base64加密方式,也可以做的比较复杂,不一定是上面的那种解决方式的,你可以添加一些较为复杂的算法在里面的。 

         /// <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 "";
                }
            }
        }

//-----------下面是MD5Util下面的函数

        
/// <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(4);
        }
        
/// <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 >= 4)
            {
                
string tmp = input.Substring(4);
                
if (input.Substring(04== GetMD5_4(tmp))
                {
                    res 
= true;
                }
            }
            
return res;
        }

 

 

 如下面代码就是上面提到的Base64Util中的内容,好像算法处理还是比较麻烦,也贴出来大家研读一下吧。

    /// <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();

        
/// <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<intchar> m_t1 = new Dictionary<intchar>();
        
protected Dictionary<charint> m_t2 = new Dictionary<charint>();

        
/// <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 < 64)
                {
                    
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 != 1)
                {
                    
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 % 3;
                
int patch = 3 - remain;
                
if (remain != 0)
                {
                    Array.Resize(
ref tmp, tmp.Length + patch);
                }
                
int cnt = (int)Math.Ceiling(tmp.Length * 1.0 / 3);
                
for (int i = 0; i < cnt; i++)
                {
                    sb.Append(
this.EncodeUnit(tmp[i * 3], tmp[i * 3 + 1], tmp[i * 3 + 2]));
                }
                
if (remain != 0)
                {
                    sb.Remove(sb.Length 
- patch, patch);
                    
for (int i = 0; i < patch; i++)
                    {
                        sb.Append(m_pad);
                    }
                }
                
return sb.ToString();
            }

        }
        
protected string EncodeUnit(params byte[] unit)
        {
            
int[] obj = new int[4];
            obj[
0= (unit[0& 0xfc>> 2;
            obj[
1= ((unit[0& 0x03<< 4+ ((unit[1& 0xf0>> 4);
            obj[
2= ((unit[1& 0x0f<< 2+ ((unit[2& 0xc0>> 6);
            obj[
3= unit[2& 0x3f;
            StringBuilder sb 
= new StringBuilder();
            
for (int i = 0; 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 % 4;
                
if (remain != 0)
                {
                    Array.Resize(
ref tmp, tmp.Length - remain);
                }
                
int patch = source.IndexOf(m_pad);
                
if (patch != -1)
                {
                    patch 
= source.Length - patch;
                }
                
int cnt = tmp.Length / 4;
                
for (int i = 0; i < cnt; i++)
                {
                    
this.DecodeUnit(list, tmp[i * 4], tmp[i * 4 + 1], tmp[i * 4 + 2], tmp[i * 4 + 3]);
                }
                
for (int i = 0; i < patch; i++)
                {
                    list.RemoveAt(list.Count 
- 1);
                }
                
return System.Text.Encoding.UTF8.GetString(list.ToArray());
            }
        }
        
protected void DecodeUnit(List<byte> byteArr, params char[] chArray)
        {
            
int[] res = new int[3];
            
byte[] unit = new byte[chArray.Length];
            
for (int i = 0; i < chArray.Length; i++)
            {
                unit[i] 
= this.FindChar(chArray[i]);
            }
            res[
0= (unit[0<< 2+ ((unit[1& 0x30>> 4);
            res[
1= ((unit[1& 0xf<< 4+ ((unit[2& 0x3c>> 2);
            res[
2= ((unit[2& 0x3<< 6+ unit[3];
            
for (int i = 0; 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[
0], -1);
            
for (int i = 0; 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 = 0; 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) > -1)
            {
                
throw new Exception("密码表中包含了补码字符:" + pad);
            }
        }

    }

 

 

 

 

 

 

 

 

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posted on 2010-09-30 11:38  伍华聪  阅读(8851)  评论(9编辑  收藏  举报

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