C# 加密类工具实例分析

//sha1加密    
public static String getSha1(String str){        
if(str==null||str.length()==0){            
return null;
        }        
        char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};        
        try {
            MessageDigest mdTemp = MessageDigest.getInstance("SHA1");
            mdTemp.update(str.getBytes("UTF-8"));            
            byte[] md = mdTemp.digest();            
            int j = md.length;            
            char buf[] = new char[j*2];            
            int k = 0;            
            for (int i = 0; i < j; i++) {                
            byte byte0 = md[i];
                buf[k++] = hexDigits[byte0 >>> 4 & 0xf];
                buf[k++] = hexDigits[byte0 & 0xf];
            }            return new String(buf);
        } catch (Exception e) {            
        return null;
        }
    }

package com.huihui.util;
import java.security.MessageDigest;
/**
 * MD5加密工具类
 * @author Administrator
 *
 */public class Md5Util {    
 public final static String MD5(String s){        
 char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'}; 
        try {            byte[] strTemp = s.getBytes();
            MessageDigest mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(strTemp);            
            byte[] md = mdTemp.digest();            
            int j = md.length;            
            char str[] = new char[j*2];            
            int k = 0;            
            for (int i = 0; i < j; i++) {                
            byte byte0 = md[i];
                str[k++] = hexDigits[byte0>>>4&0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }            return new String(str);

        } catch (Exception e) {            
        return null;
        }
    }    public static void main(String[] args) {
        System.out.println(Md5Util.MD5("b"));
    }
}