| // Copyright 2017 Google Inc. |
| // |
| // 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.google.crypto.tink.subtle; |
| |
| import java.security.SecureRandom; |
| |
| /** |
| * A simple wrapper of {@link SecureRandom}. |
| * |
| * @since 1.0.0 |
| */ |
| public final class Random { |
| private static final ThreadLocal<SecureRandom> localRandom = new ThreadLocal<SecureRandom>() { |
| @Override |
| protected SecureRandom initialValue() { |
| return newDefaultSecureRandom(); |
| } |
| }; |
| |
| private static SecureRandom newDefaultSecureRandom() { |
| SecureRandom retval = new SecureRandom(); |
| retval.nextLong(); // force seeding |
| return retval; |
| } |
| |
| /** @return a random byte array of size {@code size}. */ |
| public static byte[] randBytes(int size) { |
| byte[] rand = new byte[size]; |
| localRandom.get().nextBytes(rand); |
| return rand; |
| } |
| |
| public static final int randInt(int max) { |
| return localRandom.get().nextInt(max); |
| } |
| |
| public static final int randInt() { |
| return localRandom.get().nextInt(); |
| } |
| } |