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Added PBKDF2PasswordEncoder.

 - Also moved some logic into a new class, AbstractPasswordEncoder.
Both PBKDF2PasswordEncoder and the now-simplified
StandardPasswordEncoder extend AbstractPasswordEncoder.
 - Added tests for PBKDF2PasswordEncoder

Issue gh-2158
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rworsnop authored and rwinch committed Oct 21, 2013
1 parent d3a9cc6 commit 0ab7126e645ebcc9b6ffa445f7a29d7f1907bd2c
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/*
* 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
*
* 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.springframework.security.crypto.password;

import org.springframework.security.crypto.codec.Hex;
import org.springframework.security.crypto.keygen.BytesKeyGenerator;
import org.springframework.security.crypto.keygen.KeyGenerators;

import static org.springframework.security.crypto.util.EncodingUtils.concatenate;
import static org.springframework.security.crypto.util.EncodingUtils.subArray;

/**
* 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 = 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 concatenate(salt, encode(rawPassword, salt));
}

/**
* Constant time comparison to prevent against timing attacks.
*/
protected static boolean matches(byte[] expected, byte[] actual) {
if (expected.length != actual.length) {
return false;
}

int result = 0;
for (int i = 0; i < expected.length; i++) {
result |= expected[i] ^ actual[i];
}
return result == 0;
}
}
@@ -0,0 +1,90 @@
/*
* 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
*
* 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.springframework.security.crypto.password;

import java.security.GeneralSecurityException;

import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;

import org.springframework.security.crypto.codec.Utf8;

import static org.springframework.security.crypto.util.EncodingUtils.concatenate;

/**
* A {@code PasswordEncoder} implementation that uses PBKDF2 with a configurable number of
* iterations and a random 8-byte random salt value.
* <p>
* The width of the output hash can also be configured.
* <p>
* The algorithm is invoked on the concatenated bytes of the salt, secret and password.
*
* @author Rob Worsnop
*/
public class PBKDF2PasswordEncoder extends AbstractPasswordEncoder {
private static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA1";
private static final int DEFAULT_HASH_WIDTH = 160;
private static final int DEFAULT_ITERATIONS = 1024;

private final byte[] secret;
private final int hashWidth;
private final int iterations;

/**
* Constructs a PBKDF2 password encoder with no additional secret value. There will be
* 1024 iterations and a hash width of 160.
*/
public PBKDF2PasswordEncoder() {
this("");
}

/**
* Constructs a standard password encoder with a secret value which is also included
* in the password hash. There will be 1024 iterations and a hash width of 160.
*
* @param secret the secret key used in the encoding process (should not be shared)
*/
public PBKDF2PasswordEncoder(CharSequence secret) {
this(secret, DEFAULT_ITERATIONS, DEFAULT_HASH_WIDTH);
}

/**
* Constructs a standard password encoder with a secret value as well as iterations
* and hash.
*
* @param secret
* @param iterations
* @param hashWidth
*/
public PBKDF2PasswordEncoder(CharSequence secret, int iterations, int hashWidth) {
this.secret = Utf8.encode(secret);
this.iterations = iterations;
this.hashWidth = hashWidth;
}

@Override
protected byte[] encode(CharSequence rawPassword, byte[] salt) {
try {
PBEKeySpec spec = new PBEKeySpec(rawPassword.toString().toCharArray(),
concatenate(salt, this.secret), this.iterations, this.hashWidth);
SecretKeyFactory skf = SecretKeyFactory.getInstance(PBKDF2_ALGORITHM);
return concatenate(salt, skf.generateSecret(spec).getEncoded());
}
catch (GeneralSecurityException e) {
throw new IllegalStateException("Could not create hash", e);
}
}
}
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package org.springframework.security.crypto.password;

import org.junit.Test;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;


public class PBKDF2PasswordEncoderTests {
private PBKDF2PasswordEncoder encoder = new PBKDF2PasswordEncoder("secret");

@Test
public void matches() {
String result = encoder.encode("password");
assertFalse(result.equals("password"));
assertTrue(encoder.matches("password", result));
}

@Test
public void matchesLengthChecked() {
String result = encoder.encode("password");
assertFalse(encoder.matches("password", result.substring(0,result.length()-2)));
}

@Test
public void notMatches() {
String result = encoder.encode("password");
assertFalse(encoder.matches("bogus", result));
}

}

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