《Java实现MD5加密》.pdf

Java 实现MD5 加密以及解密类，附带测试类，具体见代码。 MD5 加密解密类——MyMD5Util,代码如下： view plaincopy to clipboardprint? package com.zyg.security.md5; import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import java.util.Arrays; public class MyMD5Util { private static final String HEX_NUMS_STR=0123456789ABCDEF; private static final Integer SALT_LENGTH = 12; /** * 将16 进制字符串转换成字节数组 * @param hex * @return */ public static byte[] hexStringToByte(String hex) { int len = (hex.length() / 2); byte[] result = new byte[len]; char[] hexChars = hex.toCharArray(); for (int i = 0; i len; i++) { int pos = i * 2; result[i] = (byte) (HEX_NUMS_STR.indexOf(hexChars[pos]) 4 | HEX_NUMS_STR.indexOf(hexChars[pos + 1])); } return result; } /** * 将指定byte 数组转换成16 进制字符串 * @param b * @return */ public static String byteToHexString(byte[] b) { StringBuffer hexString = new StringBuffer(); for (int i = 0; i b.length; i++) { String hex = Integer.toHexString(b[i] 0xFF); if (hex.length() == 1) { hex = 0 + hex; } hexString.append(hex.toUpperCase()); } return hexString.toString(); } /** * 验证口令是否合法 * @param password * @param passwordInDb * @return * @throws NoSuchAlgorithmException * @throws UnsupportedEncodingException */ public static boolean validPassword(String password, String passwordInDb) throws NoSuchAlgorithmException, UnsupportedEncodingException { //将16 进制字符串格式口令转换成字节数组 byte[] pwdInDb = hexStringToByte(passwordInDb); //声明盐变量 byte[] salt = new byte[SALT_LENGTH]; //将盐从数据库中保存的口令字节数组中提取出来 System.arraycopy(pwdInDb, 0, salt, 0, SALT_LENGTH); //创建消息摘要对象 MessageDigest md = MessageDigest.getInstance(MD5); //将盐数据传入消息摘要对象 md.update(salt); //将