//Java Encryption Using Key

//Java Encryption Using Key
//Kalo mau paspornya lebih panjang
/*
SecretKey = getSecretKey();
		byte[] md5Key = null;
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(SecretKey.getBytes("UTF-8"),0,SecretKey.length());
			md5Key = md.digest();
//			Log.d("md5Key",md.toString());
		} catch (Exception e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}

*/



import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class TestActivity extends Activity {
	private String iv = "fedcba9876543210";// Dummy iv (CHANGE IT!)
	private IvParameterSpec ivspec;
	private SecretKeySpec keyspec;
	private Cipher cipher;

//	private String SecretKey = "0123456789abcdef";// Dummy secretKey (CHANGE
//													// IT!)


	private String SecretKey = "0123456789abcdef";// Dummy secretKey (CHANGE
	// IT!)

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);





		ivspec = new IvParameterSpec(iv.getBytes());
		keyspec = new SecretKeySpec(SecretKey.getBytes(), "AES");

		try {
			cipher = Cipher.getInstance("AES/CBC/NoPadding");
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		Log.d("cipher.toString()", cipher.toString());
		Log.d("keyspec.toString()", keyspec.toString());
		Log.d("ivspec.toString()", ivspec.toString());
		Log.d("SecretKey", SecretKey);
		Log.d("iv", iv);
		String eiv = "";
		try {
			 eiv = new String(encrypt(iv), "UTF-8");
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		Log.d("eiv", eiv);
		try {
			 eiv = new String(decrypt(eiv), "UTF-8");
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		Log.d("eiv", eiv);




			/* Encrypt */
			String encrypted = "";
			try {
				encrypted = bytesToHex( encrypt("Mine Fujiko") );
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			Log.d("encrypted", encrypted);
			/* Decrypt */
			String decrypted  =  "";
			try {
				 decrypted = new String( decrypt( encrypted ) );
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			Log.d("decrypted", decrypted);
	}

	public byte[] encrypt(String text) throws Exception {
		if (text == null || text.length() == 0)
			throw new Exception("Empty string");

		byte[] encrypted = null;

		try {
			cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);

			encrypted = cipher.doFinal(padString(text).getBytes());
		} catch (Exception e) {
			throw new Exception("[encrypt] " + e.getMessage());
		}

		return encrypted;
	}

	public byte[] decrypt(String code) throws Exception {
		if (code == null || code.length() == 0)
			throw new Exception("Empty string");

		byte[] decrypted = null;

		try {
			cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

			decrypted = cipher.doFinal(hexToBytes(code));
		} catch (Exception e) {
			throw new Exception("[decrypt] " + e.getMessage());
		}
		return decrypted;
	}

	public static String bytesToHex(byte[] data) {
		if (data == null) {
			return null;
		}

		int len = data.length;
		String str = "";
		for (int i = 0; i < len; i++) {
			if ((data[i] & 0xFF) < 16)
				str = str + "0" + java.lang.Integer.toHexString(data[i] & 0xFF);
			else
				str = str + java.lang.Integer.toHexString(data[i] & 0xFF);
		}
		return str;
	}

	public static byte[] hexToBytes(String str) {
		if (str == null) {
			return null;
		} else if (str.length() < 2) {
			return null;
		} else {
			int len = str.length() / 2;
			byte[] buffer = new byte[len];
			for (int i = 0; i < len; i++) {
				buffer[i] = (byte) Integer.parseInt(
						str.substring(i * 2, i * 2 + 2), 16);
			}
			return buffer;
		}
	}

	private static String padString(String source) {
		char paddingChar = ' ';
		int size = 16;
		int x = source.length() % size;
		int padLength = size - x;

		for (int i = 0; i < padLength; i++) {
			source += paddingChar;
		}

		return source;
	}

}