package pt.ven.decryptAbsolut;

import java.security.GeneralSecurityException;
import java.security.InvalidKeyException;
import java.security.KeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.util.zip.CRC32;
import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;

import java.io.*;
import java.security.SecureRandom;
import java.util.Hashtable;
import java.util.UUID;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;




public class main {

    static Hashtable c;

    /**
     * @param args
     */
    public static void main(String[] args) {
        try {
            decryptFile("settings"); // file to decode
        } catch (KeyException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }


    }

    public static Cipher getCipher(byte abyte0[], int i, String s, String s1) throws InvalidKeyException, GeneralSecurityException, NoSuchAlgorithmException
    {
        String s2 = "DESede";
        int j = s.indexOf("/");
        if(j != -1)
            s2 = s.substring(0, j);
        DESedeKeySpec desedekeyspec = new DESedeKeySpec(abyte0);
        javax.crypto.SecretKey secretkey = SecretKeyFactory.getInstance(s2).generateSecret(desedekeyspec);
        IvParameterSpec ivparameterspec = new IvParameterSpec(a(s1));
        Cipher cipher = Cipher.getInstance(s);
        cipher.init(i, secretkey, ivparameterspec);
        return cipher;
    }

    public static byte[] a(String s)
    {
        byte abyte0[] = new byte[s.length()];
        int i = 0;
        do
        {
            if(i >= s.length())
            {
                CRC32 crc32 = new CRC32();
                crc32.update(abyte0, 0, abyte0.length);
                long l = 0xffffffffL & crc32.getValue();
                byte abyte1[] = new byte[8];
                abyte1[0] = 0;
                abyte1[1] = 0;
                abyte1[2] = 0;
                abyte1[3] = 0;
                abyte1[4] = (byte)(int)((0xffffffffff000000L & l) >> 24);
                abyte1[5] = (byte)(int)((0xff0000L & l) >> 16);
                abyte1[6] = (byte)(int)((65280L & l) >> 8);
                abyte1[7] = (byte)(int)(l & 255L);
                return abyte1;
            }
            abyte0[i] = (byte)s.charAt(i);
            i++;
        } while(true);
    }

    public static void decryptFile(String filename) throws IOException, KeyException, Exception, GeneralSecurityException
    {
        FileInputStream fileinputstream;
        ObjectInputStream objectinputstream;
        CipherInputStream cipherinputstream1;
        byte first_36_bytes[];
        Hashtable hashtable;
        byte first_24_bytes[];
        fileinputstream = new FileInputStream(filename);
        first_36_bytes = new byte[36];
        fileinputstream.read(first_36_bytes, 0, 36);
        first_24_bytes = new byte[24];
        fileinputstream.read(first_24_bytes, 0, 24);
        cipherinputstream1 = new CipherInputStream(fileinputstream, getCipher(first_24_bytes, 2, "DESede/CBC/PKCS5Padding", new String(first_36_bytes)));
        objectinputstream = new ObjectInputStream(cipherinputstream1);
        hashtable = (Hashtable) objectinputstream.readObject();
        c = hashtable;
        System.out.println(hashtable); // prints file to system.out
        objectinputstream.close();

    }
}