常用加密字符串的class,轉自OSLeague啊，作者：bigeagle

2024-07-21 02:24:31

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using system;
using system.security ;
using system.security.cryptography ;
using system.diagnostics ;
using system.web ;
using system.text ;

namespace bigeagle.util
{
 /// <summary>
 /// 一個加密類
 /// author: [email protected]
 /// date: 2001/09/25
 /// history: 2001/10/25 finished
 /// </summary>
 /// <remarks>
 /// 封裝常用的加密算法
 /// </remarks>
 public class cryptography
 {

 /// <summary>
 /// md5加密指定字符串
 /// </summary>
 /// <param name="a_strvalue">要加密的字符串</param>
 /// <returns>加密后的字符串</returns>
 public static string encryptmd5string(string a_strvalue)
 {
#if debug
 debug.assert(a_strvalue.trim() != "" , "空字符串" , "空字符串不需要加密") ;
#endif//debug

 //轉換成bytearray
 byte[] hba = ((hashalgorithm) cryptoconfig.createfromname("md5")).
 computehash(stringtobytearray(a_strvalue));

 return bytearraytostring(hba) ;
 }

 /// <summary>
 /// 判斷兩個加密字符串是否相同
 /// </summary>
 /// <param name="a_str1"></param>
 /// <param name="a_str2"></param>
 /// <returns>如果相同返回真</returns>
 public static bool issame(string a_str1 , string a_str2)
 {
 byte[] b1 = stringtobytearray(a_str1) ;
 byte[] b2 = stringtobytearray(a_str2) ;
 if(b1.length != b2.length)
 {
 return false ;
 }

 for(int i = 0 ; i < b1.length ; i ++)
 {
 if(b1[i] != b2[i])
 {
 return false ;
 }
 }

 return true ;
 }

 /// <summary>
 /// 轉換string到byte樹組
 /// </summary>
 /// <param name="s">要轉換的字符串</param>
 /// <returns>轉換的byte數組</returns>
 public static byte[] stringtobytearray(string s)
 {
 /*
 char[] ca = s.tochararray();
 byte[] ba = new byte[ca.length];
 for(int i=0; i<ba.length; i++) ba[i] = (byte)ca[i];
 return ba;*/

 return encoding.utf8.getbytes(s) ;
 }

 /// <summary>
 /// 轉換byte數組到字符串
 /// </summary>
 /// <param name="a_arrbyte">byte數組</param>
 /// <returns>字符串</returns>
 public static string bytearraytostring(byte[] a_arrbyte)
 {
 /*
 //char[] ca = new char[a_arrbyte.length] ;
 for(int i = 0 ; i < a_arrbyte.length ; i ++)
 {
 result += (char)a_arrbyte[i] ;
 }*/

 return encoding.utf8.getstring(a_arrbyte) ;
 }

 /// <summary>
 /// 3des加密字符串
 /// </summary>
 /// <param name="a_strstring">要加密的字符串</param>
 /// <param name="a_strkey">密鑰</param>
 /// <returns>加密后并經base64編碼的字符串</returns>
 /// <remarks>靜態方法，采用默認ascii編碼</remarks>
 public static string encrypt3des(string a_strstring, string a_strkey)
 {
 tripledescryptoserviceprovider des = new
 tripledescryptoserviceprovider();
 md5cryptoserviceprovider hashmd5 = new md5cryptoserviceprovider();

 des.key = hashmd5.computehash(asciiencoding.ascii.getbytes(a_strkey));
 des.mode = ciphermode.ecb;

 icryptotransform desencrypt = des.createencryptor();

 byte[] buffer = asciiencoding.ascii.getbytes(a_strstring);
 return convert.tobase64string(desencrypt.transformfinalblock
 (buffer, 0, buffer.length));
 }//end method

 /// <summary>
 /// 3des加密字符串
 /// </summary>
 /// <param name="a_strstring">要加密的字符串</param>
 /// <param name="a_strkey">密鑰</param>
 /// <param name="encoding">編碼方式</param>
 /// <returns>加密后并經base63編碼的字符串</returns>
 /// <remarks>重載，指定編碼方式</remarks>
 public static string encrypt3des(string a_strstring, string a_strkey , encoding encoding)
 {
 tripledescryptoserviceprovider des = new
 tripledescryptoserviceprovider();
 md5cryptoserviceprovider hashmd5 = new md5cryptoserviceprovider();

 des.key = hashmd5.computehash(encoding.getbytes(a_strkey));
 des.mode = ciphermode.ecb;

 icryptotransform desencrypt = des.createencryptor();

 byte[] buffer = encoding.getbytes(a_strstring);
 return convert.tobase64string(desencrypt.transformfinalblock
 (buffer, 0, buffer.length));
 }

 /// <summary>
 /// 3des解密字符串
 /// </summary>
 /// <param name="a_strstring">要解密的字符串</param>
 /// <param name="a_strkey">密鑰</param>
 /// <returns>解密后的字符串</returns>
 /// <exception cref="">密鑰錯誤</exception>
 /// <remarks>靜態方法，采用默認ascii編碼</remarks>
 public static string decrypt3des(string a_strstring, string a_strkey)
 {
 tripledescryptoserviceprovider des = new
 tripledescryptoserviceprovider();
 md5cryptoserviceprovider hashmd5 = new md5cryptoserviceprovider();

 des.key = hashmd5.computehash(asciiencoding.ascii.getbytes(a_strkey));
 des.mode = ciphermode.ecb;

 icryptotransform desdecrypt = des.createdecryptor();

 string result = "";
 try
 {
 byte[] buffer = convert.frombase64string(a_strstring);
 result = asciiencoding.ascii.getstring(desdecrypt.transformfinalblock
 (buffer, 0, buffer.length));
 }
 catch(exception e)
 {
#if debug
 console.writeline("錯誤：{0}" , e) ;
#endif//debug
 throw(new exception("invalid key or input string is not a valid base64 string" , e)) ;
 }

 return result ;
 }//end method

 /// <summary>
 /// 3des解密字符串
 /// </summary>
 /// <param name="a_strstring">要解密的字符串</param>
 /// <param name="a_strkey">密鑰</param>
 /// <param name="encoding">編碼方式</param>
 /// <returns>解密后的字符串</returns>
 /// <exception cref="">密鑰錯誤</exception>
 /// <remarks>靜態方法，指定編碼方式</remarks>
 public static string decrypt3des(string a_strstring, string a_strkey , encoding encoding)
 {
 tripledescryptoserviceprovider des = new
 tripledescryptoserviceprovider();
 md5cryptoserviceprovider hashmd5 = new md5cryptoserviceprovider();

 des.key = hashmd5.computehash(encoding.getbytes(a_strkey));
 des.mode = ciphermode.ecb;

 icryptotransform desdecrypt = des.createdecryptor();

 string result = "";
 try
 {
 byte[] buffer = convert.frombase64string(a_strstring);
 result = encoding.getstring(desdecrypt.transformfinalblock
 (buffer, 0, buffer.length));
 }
 catch(exception e)
 {
#if debug
 console.writeline("錯誤：{0}" , e) ;
#endif//debug
 throw(new exception("invalid key or input string is not a valid base64 string" , e)) ;
 }

 return result ;
 }//end method

 }
}

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