org.springframework.security.crypto.password.AbstractPasswordEncoder Maven / Gradle / Ivy
/*
* Copyright 2002-2016 the original author or authors.
*
* 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
*
* https://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.springframework.security.crypto.password;
import java.security.MessageDigest;
import org.springframework.security.crypto.codec.Hex;
import org.springframework.security.crypto.keygen.BytesKeyGenerator;
import org.springframework.security.crypto.keygen.KeyGenerators;
import org.springframework.security.crypto.util.EncodingUtils;
/**
* Abstract base class for password encoders
*
* @author Rob Worsnop
*/
public abstract class AbstractPasswordEncoder implements PasswordEncoder {
private final BytesKeyGenerator saltGenerator;
protected AbstractPasswordEncoder() {
this.saltGenerator = KeyGenerators.secureRandom();
}
@Override
public String encode(CharSequence rawPassword) {
byte[] salt = this.saltGenerator.generateKey();
byte[] encoded = encodeAndConcatenate(rawPassword, salt);
return String.valueOf(Hex.encode(encoded));
}
@Override
public boolean matches(CharSequence rawPassword, String encodedPassword) {
byte[] digested = Hex.decode(encodedPassword);
byte[] salt = EncodingUtils.subArray(digested, 0, this.saltGenerator.getKeyLength());
return matches(digested, encodeAndConcatenate(rawPassword, salt));
}
protected abstract byte[] encode(CharSequence rawPassword, byte[] salt);
protected byte[] encodeAndConcatenate(CharSequence rawPassword, byte[] salt) {
return EncodingUtils.concatenate(salt, encode(rawPassword, salt));
}
/**
* Constant time comparison to prevent against timing attacks.
*/
protected static boolean matches(byte[] expected, byte[] actual) {
return MessageDigest.isEqual(expected, actual);
}
}