Java密码加密与解密

Posted 2020-07-15

Java密码加密与解密

Java中对代码进行加密与解密，其中用MD5方式的是不可逆的。

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

@SuppressWarnings("unused")
public class PasswordUtils {
    //加密
    @SuppressWarnings({})
    public static String encrypt(String plainText) {
        String result = "";
        try {
            DESKeySpec keySpec = new DESKeySpec("CampusHelper".getBytes("UTF8"));
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey key = keyFactory.generateSecret(keySpec);
            sun.misc.BASE64Encoder base64encoder = new sun.misc.BASE64Encoder();
            sun.misc.BASE64Decoder base64decoder = new sun.misc.BASE64Decoder();

            // ENCODE plainTextPassword String
            byte[] cleartext = plainText.getBytes("UTF8");

            Cipher cipher = Cipher.getInstance("DES"); // cipher is not thread
                                                        // safe
            cipher.init(Cipher.ENCRYPT_MODE, key);
            result = base64encoder.encode(cipher.doFinal(cleartext));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
      //解密
    @SuppressWarnings({})
    public static String decrypt(String encryptedPwd)
            throws InvalidKeyException, UnsupportedEncodingException {
        String result = "";
        try {
            DESKeySpec keySpec = new DESKeySpec("CampusHelper".getBytes("UTF8"));
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey key = keyFactory.generateSecret(keySpec);
            sun.misc.BASE64Encoder base64encoder = new sun.misc.BASE64Encoder();
            sun.misc.BASE64Decoder base64decoder = new sun.misc.BASE64Decoder();

            // DECODE encryptedPwd String
            byte[] encrypedPwdBytes = base64decoder.decodeBuffer(encryptedPwd);

            Cipher cipher = Cipher.getInstance("DES");// cipher is not thread
                                                        // safe
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] plainTextPwdBytes = (cipher.doFinal(encrypedPwdBytes));
            result = new String(plainTextPwdBytes);
        } catch (Exception e) {

            System.out.println("解密失败:"+encryptedPwd);
            result=againDecrypt(encryptedPwd);
        }
        return result;
    }

    public static String againDecrypt(String encryptedPwd)
            throws InvalidKeyException, UnsupportedEncodingException {
        String result = "";
        try {
            encryptedPwd=URLDecoder.decode(encryptedPwd,"utf-8");
            DESKeySpec keySpec = new DESKeySpec("CampusHelper".getBytes("UTF8"));
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey key = keyFactory.generateSecret(keySpec);
            sun.misc.BASE64Encoder base64encoder = new sun.misc.BASE64Encoder();
            sun.misc.BASE64Decoder base64decoder = new sun.misc.BASE64Decoder();

            // DECODE encryptedPwd String
            byte[] encrypedPwdBytes = base64decoder.decodeBuffer(encryptedPwd);

            Cipher cipher = Cipher.getInstance("DES");// cipher is not thread
                                                        // safe
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] file=cipher.doFinal(encrypedPwdBytes);
            byte[] plainTextPwdBytes = (file);
            result = new String(plainTextPwdBytes);
        } catch (Exception e) {
            //e.printStackTrace();
            System.out.println("重新解密失败:"+encryptedPwd);

        }
        return result;
    }


    public static String generateMD5(String plainText) {
        String result = "";
        try {

            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(plainText.getBytes());
            byte[] digest = md.digest();
            StringBuffer sb = new StringBuffer();
            for (byte b : digest) {
                sb.append(Integer.toHexString(b & 0xff));
            }

            result = sb.toString();

        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return result;
    }

    public static void main(String[] args) {
        try {
            //System.out.println(decrypt(URLDecoder.decode("BrhT6ggt4%252BI%253D","utf-8")));
            //System.out.println(decrypt(URLDecoder.decode(URLDecoder.decode("BrhT6ggt4%252BI%253D","utf-8"))));
        //System.out.println(URLEncoder.encode(encrypt("41"), "utf-8"));
        //System.out.println(encrypt("41"));
//          long now = System.currentTimeMillis();
//          System.out.println(now);
//          now = now - now / 10000000000L * 10000000000L;
//          System.out.println(now);
                    System.out.println(decrypt("DAD0dZU0S/w/pJcrfPW4Fw=="));
            //System.out.println(encrypt("321088199511214887"));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}