很多时候要对秘要进行持久化加密，此时的加密采用md5。采用对称加密的时候就采用DES方法了
import java.io.IOException; import java.security.MessageDigest; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.SecretKey; import javax.crypto.SecretKeyFactory; import javax.crypto.spec.DESKeySpec; import sun.misc.BASEDecoder; import sun.misc.BASEEncoder; /** * 密匙工具类(包含des加密与md加密) * @author mingge * */ public class KeysUtil { private final static String DES = "DES"; private final static String MD = "MD"; private final static String KEY="opeddsaeaddadbcabf"; /** * MD加密算法 * @param data * @return */ public static String mdEncrypt(String data) { String resultString = null; try { resultString = new String(data); MessageDigest md = MessageDigest.getInstance(MD); resultString =bytehexString(md.digest(resultString.getBytes())); } catch (Exception ex) { } return resultString; } private static String bytehexString(byte[] bytes) { StringBuffer bf = new StringBuffer(bytes.length * ); for (int i = ; i < bytes.length; i++) { if ((bytes[i] & xff) < x) { bf.append("T"); } bf.append(Long.toString(bytes[i] & xff, )); } return bf.toString(); } /** * Description 根据键值进行加密 * @param data * @param key 加密键byte数组 * @return * @throws Exception */ public static String desEncrypt(String data, String key) throws Exception { if (key==null) { key=KEY; } byte[] bt = encrypt(data.getBytes(), key.getBytes()); String strs = new BASEEncoder().encode(bt); return strs; } /** * Description 根据键值进行解密 * @param data * @param key 加密键byte数组 * @return * @throws IOException * @throws Exception */ public static String desDecrypt(String data, String key) throws IOException, Exception { if (data == null){ return null; } if (key==null) { key=KEY; } BASEDecoder decoder = new BASEDecoder(); byte[] buf = decoder.decodeBuffer(data); byte[] bt = decrypt(buf,key.getBytes()); return new String(bt); } /** * Description 根据键值进行加密 * @param data * @param key 加密键byte数组 * @return * @throws Exception */ private static byte[] encrypt(byte[] data, byte[] key) throws Exception { // 生成一个可信任的随机数源 SecureRandom sr = new SecureRandom(); // 从原始密钥数据创建DESKeySpec对象 DESKeySpec dks = new DESKeySpec(key); // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES); SecretKey securekey = keyFactory.generateSecret(dks); // Cipher对象实际完成加密操作 Cipher cipher = Cipher.getInstance(DES); // 用密钥初始化Cipher对象 cipher.init(Cipher.ENCRYPT_MODE, securekey, sr); return cipher.doFinal(data); } /** * Description 根据键值进行解密 * @param data * @param key 加密键byte数组 * @return * @throws Exception */ private static byte[] decrypt(byte[] data, byte[] key) throws Exception { // 生成一个可信任的随机数源 SecureRandom sr = new SecureRandom(); // 从原始密钥数据创建DESKeySpec对象 DESKeySpec dks = new DESKeySpec(key); // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES); SecretKey securekey = keyFactory.generateSecret(dks); // Cipher对象实际完成解密操作 Cipher cipher = Cipher.getInstance(DES); // 用密钥初始化Cipher对象 cipher.init(Cipher.DECRYPT_MODE, securekey, sr); return cipher.doFinal(data); } }
下面在给大家介绍一段代码关于Java实现MD5加密解密类
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：
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); //将口令的数据传给消息摘要对象 md.update(password.getBytes("UTF-8")); //生成输入口令的消息摘要 byte[] digest = md.digest(); //声明一个保存数据库中口令消息摘要的变量 byte[] digestInDb = new byte[pwdInDb.length - SALT_LENGTH]; //取得数据库中口令的消息摘要 System.arraycopy(pwdInDb, SALT_LENGTH, digestInDb, 0, digestInDb.length); //比较根据输入口令生成的消息摘要和数据库中消息摘要是否相同 if (Arrays.equals(digest, digestInDb)) { //口令正确返回口令匹配消息 return true; } else { //口令不正确返回口令不匹配消息 return false; } } /** * 获得加密后的16进制形式口令 * @param password * @return * @throws NoSuchAlgorithmException * @throws UnsupportedEncodingException */ public static String getEncryptedPwd(String password) throws NoSuchAlgorithmException, UnsupportedEncodingException { //声明加密后的口令数组变量 byte[] pwd = null; //随机数生成器 SecureRandom random = new SecureRandom(); //声明盐数组变量 byte[] salt = new byte[SALT_LENGTH]; //将随机数放入盐变量中 random.nextBytes(salt); //声明消息摘要对象 MessageDigest md = null; //创建消息摘要 md = MessageDigest.getInstance("MD5"); //将盐数据传入消息摘要对象 md.update(salt); //将口令的数据传给消息摘要对象 md.update(password.getBytes("UTF-8")); //获得消息摘要的字节数组 byte[] digest = md.digest(); //因为要在口令的字节数组中存放盐，所以加上盐的字节长度 pwd = new byte[digest.length + SALT_LENGTH]; //将盐的字节拷贝到生成的加密口令字节数组的前12个字节，以便在验证口令时取出盐 System.arraycopy(salt, 0, pwd, 0, SALT_LENGTH); //将消息摘要拷贝到加密口令字节数组从第13个字节开始的字节 System.arraycopy(digest, 0, pwd, SALT_LENGTH, digest.length); //将字节数组格式加密后的口令转化为16进制字符串格式的口令 return byteToHexString(pwd); } }
测试类——Client,代码如下：
package com.zyg.security.md5; import java.io.UnsupportedEncodingException; import java.security.NoSuchAlgorithmException; import java.util.HashMap; import java.util.Map; public class Client { private static Map users = new HashMap(); public static void main(String[] args){ String userName = "zyg"; String password = "123"; registerUser(userName,password); userName = "changong"; password = "456"; registerUser(userName,password); String loginUserId = "zyg"; String pwd = "1232"; try { if(loginValid(loginUserId,pwd)){ System.out.println("欢迎登陆！！！"); }else{ System.out.println("口令错误，请重新输入！！！"); } } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 注册用户 * * @param userName * @param password */ public static void registerUser(String userName,String password){ String encryptedPwd = null; try { encryptedPwd = MyMD5Util.getEncryptedPwd(password); users.put(userName, encryptedPwd); } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 验证登陆 * * @param userName * @param password * @return * @throws UnsupportedEncodingException * @throws NoSuchAlgorithmException */ public static boolean loginValid(String userName,String password) throws NoSuchAlgorithmException, UnsupportedEncodingException{ String pwdInDb = (String)users.get(userName); if(null!=pwdInDb){ // 该用户存在 return MyMD5Util.validPassword(password, pwdInDb); }else{ System.out.println("不存在该用户！！！"); return false; } } }
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