1 /* 2 * Copyright (C) 2019 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.internal.net.eap.crypto; 18 19 import com.android.internal.net.crypto.KeyGenerationUtils; 20 import com.android.internal.net.crypto.KeyGenerationUtils.ByteSigner; 21 22 import java.security.InvalidKeyException; 23 import java.security.NoSuchAlgorithmException; 24 25 import javax.crypto.Mac; 26 import javax.crypto.spec.SecretKeySpec; 27 28 /** 29 * HmacSha256ByteSigner is a {@link ByteSigner} to be used for computing HMAC-SHA-256 values for 30 * specific keys and data. 31 */ 32 public class HmacSha256ByteSigner implements KeyGenerationUtils.ByteSigner { 33 private static final String TAG = HmacSha256ByteSigner.class.getSimpleName(); 34 private static final String MAC_ALGORITHM_STRING = "HmacSHA256"; 35 private static final HmacSha256ByteSigner sInstance = new HmacSha256ByteSigner(); 36 37 /** 38 * Gets instance of HmacSha256ByteSigner. 39 * 40 * @return HmacSha256ByteSigner instance. 41 */ getInstance()42 public static HmacSha256ByteSigner getInstance() { 43 return sInstance; 44 } 45 46 @Override signBytes(byte[] keyBytes, byte[] dataToSign)47 public byte[] signBytes(byte[] keyBytes, byte[] dataToSign) { 48 try { 49 Mac mac = Mac.getInstance(MAC_ALGORITHM_STRING); 50 mac.init(new SecretKeySpec(keyBytes, MAC_ALGORITHM_STRING)); 51 return mac.doFinal(dataToSign); 52 } catch (NoSuchAlgorithmException | InvalidKeyException ex) { 53 throw new IllegalArgumentException(ex); 54 } 55 } 56 } 57