DES加密

最近项目有这样一个需求，要求把数据加密放入数据库，用到的时候还要解密，MD5加密可以，但不能解密，现提供DES算法，没必要研究它怎么实现的，拿过去直接用就是了

import java.security.*;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class DESPlus{
	private static final String PASSWORD_CRYPT_KEY = "__jDlog_";

	private final static String DES = "DES";

	public static byte[] encrypt(byte[] src, byte[] key) throws Exception {
		SecureRandom sr = new SecureRandom();
		DESKeySpec dks = new DESKeySpec(key);
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);
		Cipher cipher = Cipher.getInstance(DES);
		cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
		return cipher.doFinal(src);
	}

	public static byte[] decrypt(byte[] src, byte[] key) throws Exception {
		SecureRandom sr = new SecureRandom();
		DESKeySpec dks = new DESKeySpec(key);
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);
		Cipher cipher = Cipher.getInstance(DES);
		cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
		return cipher.doFinal(src);
	}

	/**
	 * 密码解密
	 * 
	 */
	public final static String decrypt(String data) {
		try {
			return new String(decrypt(hex2byte(data.getBytes()),
					PASSWORD_CRYPT_KEY.getBytes()));
		} catch (Exception e) {
		}
		return null;
	}

	/**
	 * 密码加密
	 * 
	 */
	public final static String encrypt(String password) {
		try {
			return byte2hex(encrypt(password.getBytes(), PASSWORD_CRYPT_KEY
					.getBytes()));
		} catch (Exception e) {
		}
		return null;
	}

	public 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;
		}
		return hs.toUpperCase();
	}

	public static byte[] hex2byte(byte[] b) {
		if ((b.length % 2) != 0)
			throw new IllegalArgumentException("长度不是偶数");
		byte[] b2 = new byte[b.length / 2];
		for (int n = 0; n < b.length; n += 2) {
			String item = new String(b, n, 2);
			b2[n / 2] = (byte) Integer.parseInt(item, 16);
		}
		return b2;
	}
	
	public static void main(String[] args) {
		try {
			String test = "测试一把";
			System.out.println("加密前的字符：" + test + "\t" + test.length());
			System.out.println("加密后的字符：" + StringUtil.encrypt(test) + "\t" + StringUtil.encrypt(test).length());
			System.out.println("解密后的字符：" + StringUtil.decrypt(StringUtil.encrypt(test)) + "\t" + StringUtil.decrypt(StringUtil.encrypt(test)).length());
		} catch (Exception e) { 
			e.printStackTrace();
		}
	}
}

运行结果如下

加密前的字符：测试一把	4
加密后的字符：877F9350EA8125F58311435A70E2DE90	32
解密后的字符：测试一把	4