Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class Main {
    public static byte[] getDecCode(byte[] byteD, String seed) {
        byte[] byteFina = null;
        Cipher cipher = null;

        try {
            SecretKeySpec skeySpec = new SecretKeySpec(getRawKey(seed.getBytes()), "AES");
            cipher = Cipher.getInstance("AES/CFB/NoPadding");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(new byte[cipher.getBlockSize()]));
            byteFina = cipher.doFinal(byteD);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            cipher = null;
        }

        return byteFina;
    }

    private static byte[] getRawKey(byte[] seed) throws NoSuchAlgorithmException, NoSuchProviderException {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        SecureRandom sr = null;
        if (android.os.Build.VERSION.SDK_INT >= 17) {
            sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
        } else {
            sr = SecureRandom.getInstance("SHA1PRNG");
        }
        sr.setSeed(seed);
        kgen.init(128, sr); //256 bits or 128 bits,192bits  
        SecretKey skey = kgen.generateKey();
        byte[] raw = skey.getEncoded();
        return raw;
    }
}