/*
* Copyright (c) 2008 Bradley W. Kimmel
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package ca.eandb.util.auth;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.util.Arrays;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import ca.eandb.util.UnexpectedException;
/**
* Implements one-way hashes for passwords. Based on
* <a href="http://www.javacodegeeks.com/2012/05/secure-password-storage-donts-dos-and.html">Secure
* Password Storage Donts, dos and a Java example</a>.
* @author Brad Kimmel
*/
public final class PasswordEncryptionService {
public boolean authenticate(String attemptedPassword,
byte[] encryptedPassword, byte[] salt) {
// Encrypt the clear-text password using the same salt that was used to
// encrypt the original password
byte[] encryptedAttemptedPassword = getEncryptedPassword(
attemptedPassword, salt);
// Authentication succeeds if encrypted password that the user entered
// is equal to the stored hash
return Arrays.equals(encryptedPassword, encryptedAttemptedPassword);
}
public byte[] getEncryptedPassword(String password, byte[] salt) {
// PBKDF2 with SHA-1 as the hashing algorithm. Note that the NIST
// specifically names SHA-1 as an acceptable hashing algorithm for
// PBKDF2
String algorithm = "PBKDF2WithHmacSHA1";
// SHA-1 generates 160 bit hashes, so that's what makes sense here
int derivedKeyLength = 160;
// Pick an iteration count that works for you. The NIST recommends at
// least 1,000 iterations:
// http://csrc.nist.gov/publications/nistpubs/800-132/nist-sp800-132.pdf
// iOS 4.x reportedly uses 10,000:
// http://blog.crackpassword.com/2010/09/smartphone-forensics-cracking-blackberry-backup-passwords/
int iterations = 20000;
KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, iterations,
derivedKeyLength);
try {
SecretKeyFactory f = SecretKeyFactory.getInstance(algorithm);
return f.generateSecret(spec).getEncoded();
} catch (InvalidKeySpecException e) {
throw new UnexpectedException(e);
} catch (NoSuchAlgorithmException e) {
throw new UnexpectedException(e);
}
}
public byte[] generateSalt() {
try {
// VERY important to use SecureRandom instead of just Random
SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
// Generate a 8 byte (64 bit) salt as recommended by RSA PKCS5
byte[] salt = new byte[8];
random.nextBytes(salt);
return salt;
} catch (NoSuchAlgorithmException e) {
throw new UnexpectedException(e);
}
}
}