import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;
import java.util.Random;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
 
public class TestDecodePass {
 
    public static void main(String[] args) throws Exception {
        // 如果没有提供参数，显示使用方法
 
//        if (args.length == 0) {
//            System.out.println("使用方法:");
//            System.out.println("1.从Finalshell导出配置文件");
//            System.out.println("2.在配置文件中搜索password字段，复制编码后的字符串");
//            System.out.println("3.运行: java TestDecodePass [编码后的密码字符串]");
//            System.out.println("\n示例:");
//            System.out.println("java TestDecodePass \"示例密码字符串\"");
//            return;
//        }
//        String encodedPass = args[0];//被外部调用这样写，并取消以上的注释
 
        String encodedPass = "替换加密的密码";// 密码是1
        String decodedPass = decodePass(encodedPass);
        System.out.println("解密后的密码:" + decodedPass);
    }
 
    public static byte[] desDecode(byte[] data, byte[] head) throws Exception {
        SecureRandom sr = new SecureRandom();
        DESKeySpec dks = new DESKeySpec(head);
        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(data);
    }
 
    public static String decodePass(String data) throws Exception {
        if (data == null) {
            return null;
        } else {
            String rs = "";
            byte[] buf = Base64.getDecoder().decode(data);
            byte[] head = new byte[8];
            System.arraycopy(buf, 0, head, 0, head.length);
            byte[] d = new byte[buf.length - head.length];
            System.arraycopy(buf, head.length, d, 0, d.length);
            byte[] bt = desDecode(d, ranDomKey(head));
            rs = new String(bt);
            return rs;
        }
    }
 
    static byte[] ranDomKey(byte[] head) {
        long ks = 3680984568597093857L / (long) (new Random((long) head[5])).nextInt(127);
        Random random = new Random(ks);
        int t = head[0];
        for (int i = 0; i < t; ++i) {
            random.nextLong();
        }
        long n = random.nextLong();
        Random r2 = new Random(n);
        long[] ld = new long[]{
                (long) head[4],
                r2.nextLong(),
                (long) head[7],
                (long) head[3],
                r2.nextLong(),
                (long) head[1],
                random.nextLong(),
                (long) head[2]
        };
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(bos);
        for (long l : ld) {
            try {
                dos.writeLong(l);
            } catch (IOException var18) {
                var18.printStackTrace();
            }
        }
        try {
            dos.close();
        } catch (IOException var17) {
            var17.printStackTrace();
        }
        byte[] keyData = bos.toByteArray();
        keyData = md5(keyData);
        return keyData;
    }
 
    public static byte[] md5(byte[] data) {
        byte[] res = null;
        try {
            MessageDigest m = MessageDigest.getInstance("MD5");
            m.update(data, 0, data.length);
            res = m.digest();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return res;
    }
}