HmacSHA256.java

package io.netty.protocol.wamp.cra;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

public class HmacSHA256 {
	public static final String HMAC_SHA256 = "HmacSHA256";

	public static String generate(final String key, final String data) throws NoSuchAlgorithmException, InvalidKeyException {
		if (key == null || data == null) throw new NullPointerException();
		final Mac hMacSHA256 = Mac.getInstance(HMAC_SHA256);
		byte[] hmacKeyBytes = key.getBytes(StandardCharsets.UTF_8);
		final SecretKeySpec secretKey = new SecretKeySpec(hmacKeyBytes, HMAC_SHA256);
		hMacSHA256.init(secretKey);
		byte[] dataBytes = data.getBytes(StandardCharsets.UTF_8);
		byte[] res = hMacSHA256.doFinal(dataBytes);
		return Base64.encodeBase64String(res);
	}
}