org.fisco.bcos.sdk.v3.utils.LinuxSecureRandom Maven / Gradle / Ivy
/*
* Copyright 2013 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 org.fisco.bcos.sdk.v3.utils;
import java.io.*;
import java.security.Provider;
import java.security.SecureRandomSpi;
import java.security.Security;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Implementation from BitcoinJ
* implementation
*
* A SecureRandom implementation that is able to override the standard JVM provided
* implementation, and which simply serves random numbers by reading /dev/urandom. That is, it
* delegates to the kernel on UNIX systems and is unusable on other platforms. Attempts to manually
* set the seed are ignored. There is no difference between seed bytes and non-seed bytes, they are
* all from the same source.
*/
public class LinuxSecureRandom extends SecureRandomSpi {
private static final FileInputStream urandom;
private static class LinuxSecureRandomProvider extends Provider {
public LinuxSecureRandomProvider() {
super(
"LinuxSecureRandom",
1.0,
"A Linux specific random number provider that uses /dev/urandom");
put("SecureRandom.LinuxSecureRandom", LinuxSecureRandom.class.getName());
}
}
private static final Logger log = LoggerFactory.getLogger(LinuxSecureRandom.class);
static {
try {
File file = new File("/dev/urandom");
// This stream is deliberately leaked.
urandom = new FileInputStream(file);
if (urandom.read() == -1) {
throw new RuntimeException("/dev/urandom not readable?");
}
// Now override the default SecureRandom implementation with this one.
int position = Security.insertProviderAt(new LinuxSecureRandomProvider(), 1);
if (position != -1) {
log.info("Secure randomness will be read from {} only.", file);
} else {
log.info("Randomness is already secure.");
}
} catch (FileNotFoundException e) {
// Should never happen.
log.error("/dev/urandom does not appear to exist or is not openable");
throw new RuntimeException(e);
} catch (IOException e) {
log.error("/dev/urandom does not appear to be readable");
throw new RuntimeException(e);
}
}
private final DataInputStream dis;
public LinuxSecureRandom() {
// DataInputStream is not thread safe, so each random object has its own.
dis = new DataInputStream(urandom);
}
@Override
protected void engineSetSeed(byte[] bytes) {
// Ignore.
}
@Override
protected void engineNextBytes(byte[] bytes) {
try {
dis.readFully(bytes); // This will block until all the bytes can be read.
} catch (IOException e) {
throw new RuntimeException(e); // Fatal error. Do not attempt to recover from this.
}
}
@Override
protected byte[] engineGenerateSeed(int i) {
byte[] bits = new byte[i];
engineNextBytes(bits);
return bits;
}
}