digest.java

SSH示范

package com.iplan.portal.framework.utils;

import java.security.MessageDigest;

/**
 * 常用的MD5和SHA-1
 * MD5是麻省理工大学推出的，而SHA－1是美国技术协会标准
 * 
 * 简单的单项散列函数消息处理。
 * <p>
 * http://www.hao-se.cn
 * </p>
 * 
 * @author ws
 */
public class Digest {
	/**
	 * 信息显示
	 * 
	 * 二行制转字符串
	 * 
	 * param b return
	 * 
	 */
	private static String byte2hex(byte[] b) {
		String hs = "";
		String stmp = "";
		for (int n = 0; n < b.length; n++) {
			stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));

			if (stmp.length() == 1)
				hs = hs + "0" + stmp;
			else
				hs = hs + stmp;
			if (n < b.length - 1)
				hs = hs + ":";
		}
		return hs.toUpperCase();
	}

	/**
	 * 
	 * 用MD5校验信息是否更改.
	 * 
	 * @param myInfo
	 * @param digestInfo
	 * @return
	 */
	public static boolean checkMD5Digest(String myInfo, String digestInfo) {

		if (myInfo == null || digestInfo == null)
			return false;

		try {
			MessageDigest alga = MessageDigest.getInstance("MD5");

			alga.update(myInfo.getBytes());

			byte[] digesta = alga.digest();

			return digestInfo.equals(byte2hex(digesta));

		} catch (java.security.NoSuchAlgorithmException ex) {
			System.out.println("非法摘要算法");
			throw new RuntimeException();
		}
	}

//	/**
//	 * 
//	 * 用SHA-1校验信息是否更改.
//	 * 
//	 * @param myInfo
//	 * @param digestInfo
//	 * @return
//	 */
//	public static boolean checkSHA1Digest(String myInfo, String digestInfo) {
//
//		if (myInfo == null || digestInfo == null)
//			return false;
//
//		try {
//			MessageDigest alga = MessageDigest.getInstance("SHA-1");
//
//			alga.update(myInfo.getBytes());
//
//			byte[] digesta = alga.digest();
//
//			return digestInfo.equals(byte2hex(digesta));
//
//		} catch (java.security.NoSuchAlgorithmException ex) {
//			System.out.println("非法摘要算法");
//			throw new RuntimeException();
//		}
//	}

	/**
	 * 
	 * 根据字符信息用MD5加密,返回
	 * 
	 * @param myInfo
	 * @return
	 * @throws Exception
	 */
	public static String getMD5Digest(String myInfo) throws Exception {

		if (myInfo == null)
			return "";

		try {

			MessageDigest alg = MessageDigest.getInstance("MD5");

			alg.update(myInfo.getBytes());

			byte[] digesta = alg.digest();

			return byte2hex(digesta);

		} catch (java.security.NoSuchAlgorithmException ex) {
			System.out.println("非法摘要算法");
			throw new RuntimeException();
		}
	}

//	/**
//	 * 
//	 * 根据字符信息用SHA-1加密,返回
//	 * 
//	 * @param myInfo
//	 * @return
//	 */
//	public static String getSHA1Digest(String myInfo) throws Exception {
//
//		if (myInfo == null)
//			return "";
//
//		try {
//			MessageDigest alg = MessageDigest.getInstance("SHA-1");
//
//			alg.update(myInfo.getBytes());
//
//			byte[] digesta = alg.digest();
//
//			return byte2hex(digesta);
//
//		} catch (java.security.NoSuchAlgorithmException ex) {
//			System.out.println("非法摘要算法");
//			throw new RuntimeException();
//		}
//	}

	public static void main(String args[]) throws Exception {
		String a = Digest.getMD5Digest("xy419");
		System.out.println(a);
		System.out.println(a.length());
		System.out.println(Digest.checkMD5Digest("aaaa", a));
	}

}