Java加密算法

import java.security.*;

public class MessageCheck {

 public static void main(String[] args) {
  
  String info1 = "admin";
  //String info1 = "Hello World!";
  String info2 = "Hello World!";
  
  try {
   // 生成 MessageDigest 实例，确定计算方法
   //MessageDigest md1 = MessageDigest.getInstance("SHA-1");
   MessageDigest md1 = MessageDigest.getInstance("MD5");

   // 添加要计算的摘要信息
   md1.update(info1.getBytes());  // transform parameter to byte[]

   // 完成哈希计算,返回计算得到的摘要(对于MD5是16位,SHA是20位)
   byte[] digA = md1.digest();

   // 
   MessageDigest md2 = MessageDigest.getInstance("SHA-1");
   md2.update(info2.getBytes());
   byte[] digB = md2.digest();
   
   // 比较两信息是否相等
   if (md2.isEqual(digA, digB)) {
    System.out.println("两信息相等，检查正常！");
    System.out.println(hasString(digA) + "\n" + hasString(digB));
   }
   else {
    System.out.println("两信息不相等，摘要不相同！");
    System.out.println(hasString(digA) + "\n" + hasString(digB));
   }
  } catch (NoSuchAlgorithmException e) {
   System.out.println("非法摘要算法！");
   e.printStackTrace();
  }
 }
 
 public static String hasString(byte[] b) {
  String has = "", tmp = "";

  for (int i = 0; i < b.length; i++) {
   // 以十六进制的无符号整数形式返回一个整数参数的字符串表示形式
   tmp=(java.lang.Integer.toHexString(b[i] & 0XFF));
   if (tmp.length() == 1)
    has = has + "0" + tmp;
   else
    has = has + tmp;
   if (i < b.length - 1)  has = has + ":";
  }
  return has.toUpperCase();
 }

}

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