Android AES Decrypt decrypt(byte[] key, byte[] encrypted)

Description

decrypt

Declaration

private static byte[] decrypt(byte[] key, byte[] encrypted)
            throws Exception 

Method Source Code

//package com.java2s;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;
import android.os.Build;

public class Main {
    public static String decrypt(String key, String encrypted)
            throws Exception {
        byte[] rawKey = getRawKey(key.getBytes());
        byte[] enc = toByte(encrypted);
        byte[] result = decrypt(rawKey, enc);
        return new String(result);
    }/* w w w.j  a  va2  s.c  om*/

    private static byte[] decrypt(byte[] key, byte[] encrypted)
            throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        byte[] decrypted = cipher.doFinal(encrypted);
        return decrypted;
    }

    private static byte[] getRawKey(byte[] seed) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        SecureRandom sr = null;
        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
        } else if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
        } else {
            sr = SecureRandom.getInstance("SHA1PRNG");
        }
        sr.setSeed(seed);
        kgen.init(256, sr); //256 bits or 128 bits,192bits  
        SecretKey skey = kgen.generateKey();
        byte[] raw = skey.getEncoded();
        return raw;
    }

    public static byte[] toByte(String hexString) {
        int len = hexString.length() / 2;
        byte[] result = new byte[len];
        for (int i = 0; i < len; i++)
            result[i] = Integer.valueOf(
                    hexString.substring(2 * i, 2 * i + 2), 16).byteValue();
        return result;
    }
}

Related

1. decrypt(byte[] data, Key key)
2. decrypt(byte[] data, Key key, String cipherAlgorithm)
3. decrypt(byte[] data, byte[] key)
4. decrypt(byte[] data, byte[] key, String cipherAlgorithm)
5. decrypt(byte[] encryptSource)
6. decrypt(byte[] key, byte[] src)
7. decrypt(byte[] raw, byte[] encrypted)
8. decrypt(byte[] raw, byte[] encrypted)
9. decrypt(byte[] raw, byte[] encrypted)