| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.sshd.common.util.security.bouncycastle; |
| |
| import java.security.SecureRandom; |
| |
| import org.apache.sshd.common.random.AbstractRandom; |
| import org.apache.sshd.common.util.ValidateUtils; |
| import org.apache.sshd.common.util.security.SecurityUtils; |
| import org.bouncycastle.crypto.prng.RandomGenerator; |
| import org.bouncycastle.crypto.prng.VMPCRandomGenerator; |
| |
| /** |
| * BouncyCastle <code>Random</code>. This pseudo random number generator uses the a very fast PRNG from BouncyCastle. |
| * The JRE random will be used when creating a new generator to add some random data to the seed. |
| * |
| * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a> |
| */ |
| public final class BouncyCastleRandom extends AbstractRandom { |
| public static final String NAME = SecurityUtils.BOUNCY_CASTLE; |
| private final RandomGenerator random; |
| |
| public BouncyCastleRandom() { |
| ValidateUtils.checkTrue(SecurityUtils.isBouncyCastleRegistered(), "BouncyCastle not registered"); |
| this.random = new VMPCRandomGenerator(); |
| byte[] seed = new SecureRandom().generateSeed(8); |
| this.random.addSeedMaterial(seed); |
| } |
| |
| @Override |
| public String getName() { |
| return NAME; |
| } |
| |
| @Override |
| public void fill(byte[] bytes, int start, int len) { |
| this.random.nextBytes(bytes, start, len); |
| } |
| |
| /** |
| * Returns a pseudo-random uniformly distributed {@code int} in the half-open range [0, n). |
| */ |
| @Override |
| public int random(int n) { |
| ValidateUtils.checkTrue(n > 0, "Limit must be positive: %d", n); |
| if ((n & -n) == n) { |
| return (int) ((n * (long) next(31)) >> 31); |
| } |
| |
| int bits; |
| int val; |
| do { |
| bits = next(31); |
| val = bits % n; |
| } while (bits - val + (n - 1) < 0); |
| return val; |
| } |
| |
| private int next(int numBits) { |
| int bytes = (numBits + 7) / 8; |
| byte[] next = new byte[bytes]; |
| int ret = 0; |
| random.nextBytes(next); |
| for (int i = 0; i < bytes; i++) { |
| ret = (next[i] & 0xFF) | (ret << 8); |
| } |
| return ret >>> (bytes * 8 - numBits); |
| } |
| } |