| /* |
| * Copyright 2021 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.server.nearby.common.bluetooth.fastpair; |
| |
| import static com.android.server.nearby.common.bluetooth.fastpair.AesEcbSingleBlockEncryption.generateKey; |
| |
| import com.android.server.nearby.common.bluetooth.fastpair.Constants.FastPairService.AccountKeyCharacteristic; |
| |
| import java.security.NoSuchAlgorithmException; |
| |
| /** |
| * This is to generate account key with fast-pair style. |
| */ |
| public final class AccountKeyGenerator { |
| |
| // Generate a key where the first byte is always defined as the type, 0x04. This maintains 15 |
| // bytes of entropy in the key while also allowing providers to verify that they have received |
| // a properly formatted key and decrypted it correctly, minimizing the risk of replay attacks. |
| |
| /** |
| * Creates account key. |
| */ |
| public static byte[] createAccountKey() throws NoSuchAlgorithmException { |
| byte[] accountKey = generateKey(); |
| accountKey[0] = AccountKeyCharacteristic.TYPE; |
| return accountKey; |
| } |
| |
| private AccountKeyGenerator() { |
| } |
| } |