AES Encryption and Decryption in android

public class MainActivity extends Activity {

       String seedValue = "Ohmlok";

      

       @Override

       protected void onCreate(Bundle savedInstanceState) {

              super.onCreate(savedInstanceState);

                 String normalText = "VIJAY";

              String normalTextEnc;

                     try {

                               normalTextEnc = AESHelper.encrypt(seedValue, normalText);

                               String normalTextDec = AESHelper.decrypt(seedValue, normalTextEnc);

                             TextView txe = new TextView(this);

                             txe.setTextSize(14);

                             txe.setText("Normal Text ::"+normalText +" \n Encrypted Value :: "+normalTextEnc +" \n Decrypted value :: "+normalTextDec);

                             setContentView(txe);

                     } catch (Exception e) {

                           // TODO Auto-generated catch block

                           e.printStackTrace();

                     }

           

           

       }

AESHelper class

package com.example.encription;

import java.security.SecureRandom;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

public class AESHelper {

        public static String encrypt(String seed, String cleartext) throws Exception {

                byte[] rawKey = getRawKey(seed.getBytes());

                byte[] result = encrypt(rawKey, cleartext.getBytes());

                return toHex(result);

        }

       

        public static String decrypt(String seed, String encrypted) throws Exception {

                byte[] rawKey = getRawKey(seed.getBytes());

                byte[] enc = toByte(encrypted);

                byte[] result = decrypt(rawKey, enc);

                return new String(result);

        }

        private static byte[] getRawKey(byte[] seed) throws Exception {

                KeyGenerator kgen = KeyGenerator.getInstance("AES");

                SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");

                sr.setSeed(seed);

            kgen.init(128, sr); // 192 and 256 bits may not be available

            SecretKey skey = kgen.generateKey();

            byte[] raw = skey.getEncoded();

            return raw;

        }

       

        private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {

            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

                Cipher cipher = Cipher.getInstance("AES");

            cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

            byte[] encrypted = cipher.doFinal(clear);

                return encrypted;

        }

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

            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

                Cipher cipher = Cipher.getInstance("AES");

            cipher.init(Cipher.DECRYPT_MODE, skeySpec);

            byte[] decrypted = cipher.doFinal(encrypted);

                return decrypted;

        }

        public static String toHex(String txt) {

                return toHex(txt.getBytes());

        }

        public static String fromHex(String hex) {

                return new String(toByte(hex));

        }

       

        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;

        }

        public static String toHex(byte[] buf) {

                if (buf == null)

                        return "";

                StringBuffer result = new StringBuffer(2*buf.length);

                for (int i = 0; i < buf.length; i++) {

                        appendHex(result, buf[i]);

                }

                return result.toString();

        }

        private final static String HEX = "0123456789ABCDEF";

        private static void appendHex(StringBuffer sb, byte b) {

                sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));

        }

       

}