org.cryptomator.cryptolib.common.MacSupplier Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of cryptolib Show documentation

This library contains all cryptographic functions that are used by Cryptomator.

There is a newer version: 2.2.0

/*******************************************************************************
 * Copyright (c) 2016 Sebastian Stenzel and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the accompanying LICENSE.txt.
 *
 * Contributors:
 *     Sebastian Stenzel - initial API and implementation
 *******************************************************************************/
package org.cryptomator.cryptolib.common;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Mac;
import javax.crypto.SecretKey;

public final class MacSupplier {

	public static final MacSupplier HMAC_SHA256 = new MacSupplier("HmacSHA256");

	private final String macAlgorithm;
	private final ThreadLocal threadLocal;

	public MacSupplier(String macAlgorithm) {
		this.macAlgorithm = macAlgorithm;
		this.threadLocal = new Provider();
	}

	private class Provider extends ThreadLocal {
		@Override
		protected Mac initialValue() {
			try {
				return Mac.getInstance(macAlgorithm);
			} catch (NoSuchAlgorithmException e) {
				throw new IllegalArgumentException("Invalid MAC algorithm.", e);
			}
		}
	}

	public Mac withKey(SecretKey key) {
		try {
			final Mac mac = threadLocal.get();
			mac.init(key);
			return mac;
		} catch (InvalidKeyException e) {
			throw new IllegalArgumentException("Invalid key.", e);
		}
	}

}