Android How to - Get AES Key from byte array

Question

We would like to know how to get AES Key from byte array.
Answer

//from w  ww  .j a va  2 s . c o m
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

 class AESUtility {
    public static byte[] getKey(byte[] input) throws NoSuchAlgorithmException {
        KeyGenerator generator = KeyGenerator.getInstance("AES");
        SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
        random.setSeed(input);
        generator.init(128, random);
        SecretKey key = generator.generateKey();
        byte[] raw = key.getEncoded();
        return raw;
    }

    public static byte[] encrypt(byte[] key, byte[] input) throws Exception {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "AES"));
        byte[] encrypted = cipher.doFinal(input);
        return encrypted;
    }

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

}