package random;
/**
 * Get random number from JavaCard.
 *
 * @copyright   Copyright 2013-2015 深圳市三艾斯科技有限公司
 * @license     LGPL
 * @author      Feineng Xiang<sal@3scard.com>
 * @version     1.0
 * @link        http://www.3scard.com/
 */

import javacard.framework.*;
import javacard.security.*;

public class RandomNumberApplet extends Applet {

	private RandomData randomData;
	
	public RandomNumberApplet() {
		randomData = RandomData.getInstance(RandomData.ALG_SECURE_RANDOM);
	}
	
	public static void install(byte[] bArray, short bOffset, byte bLength) {
		// GP-compliant JavaCard applet registration
		new RandomNumberApplet().register(bArray, (short) (bOffset + 1),
				bArray[bOffset]);
	}

	public void process(APDU apdu) {
		// Good practice: Return 9000 on SELECT
		if (selectingApplet()) {
			return;
		}

		byte[] buf = apdu.getBuffer();
		switch (buf[ISO7816.OFFSET_INS]) {
		case (byte) 0x84:
			short randomLen = buf[4];
			randomData.generateData(buf, (short)0, randomLen);
			apdu.setOutgoingAndSend((short)0, randomLen);
			break;
		default:
			// good practice: If you don't know the INStruction, say so:
			ISOException.throwIt(ISO7816.SW_INS_NOT_SUPPORTED);
		}
	}

}