grails.plugin.springsecurity.authentication.encoding.PBKDF2PasswordEncoder.java Source code

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Here is the source code for grails.plugin.springsecurity.authentication.encoding.PBKDF2PasswordEncoder.java

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/* Copyright 2013-2015 SpringSource.
 *
 * 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 grails.plugin.springsecurity.authentication.encoding;

import java.math.BigInteger;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;

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

/**
 * PBKDF2 salted password hashing, from https://crackstation.net/hashing-security.htm
 *
 * @author havoc AT defuse.ca
 * @author <a href='mailto:burt@burtbeckwith.com'>Burt Beckwith</a>
 */
@SuppressWarnings("deprecation")
public class PBKDF2PasswordEncoder implements org.springframework.security.authentication.encoding.PasswordEncoder {

    public static final String PBKDF2_ALGORITHM = "PBKDF2WithHmacSHA1";

    // The following constants may be changed without breaking existing hashes.
    public static final int SALT_BYTE_SIZE = 24;
    public static final int HASH_BYTE_SIZE = 24;
    public static final int PBKDF2_ITERATIONS = 1000;

    public static final int ITERATION_INDEX = 0;
    public static final int SALT_INDEX = 1;
    public static final int PBKDF2_INDEX = 2;

    public String encodePassword(String rawPass, Object saltIgnored) {
        char[] password = rawPass.toCharArray();

        // Generate a random salt
        byte[] salt = new byte[SALT_BYTE_SIZE];
        new SecureRandom().nextBytes(salt);

        // Hash the password
        byte[] hash = pbkdf2(password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE);

        // format iterations:salt:hash
        return PBKDF2_ITERATIONS + ":" + toHex(salt) + ":" + toHex(hash);
    }

    public boolean isPasswordValid(String encPass, String rawPass, Object saltIgnored) {
        char[] password = rawPass.toCharArray();

        // Decode the hash into its parameters
        String[] params = encPass.split(":");
        int iterations = Integer.parseInt(params[ITERATION_INDEX]);
        byte[] salt = fromHex(params[SALT_INDEX]);
        byte[] hash = fromHex(params[PBKDF2_INDEX]);
        // Compute the hash of the provided password, using the same salt, iteration count, and hash length
        byte[] testHash = pbkdf2(password, salt, iterations, hash.length);
        // Compare the hashes in constant time. The password is correct if both hashes match.
        return slowEquals(hash, testHash);
    }

    /**
     * Compares two byte arrays in length-constant time. This comparison method
     * is used so that password hashes cannot be extracted from an on-line
     * system using a timing attack and then attacked off-line.
     *
     * @param   a       the first byte array
     * @param   b       the second byte array
     * @return          true if both byte arrays are the same, false if not
     */
    protected boolean slowEquals(byte[] a, byte[] b) {
        int diff = a.length ^ b.length;
        for (int i = 0; i < a.length && i < b.length; i++) {
            diff |= a[i] ^ b[i];
        }
        return diff == 0;
    }

    /**
     * Computes the PBKDF2 hash of a password.
     *
     * @param   password    the password to hash.
     * @param   salt        the salt
     * @param   iterations  the iteration count (slowness factor)
     * @param   bytes       the length of the hash to compute in bytes
     * @return              the PBDKF2 hash of the password
     */
    protected byte[] pbkdf2(char[] password, byte[] salt, int iterations, int bytes) {
        PBEKeySpec spec = new PBEKeySpec(password, salt, iterations, bytes * 8);
        try {
            return SecretKeyFactory.getInstance(PBKDF2_ALGORITHM).generateSecret(spec).getEncoded();
        } catch (InvalidKeySpecException e) {
            throw new RuntimeException(e);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Converts a string of hexadecimal characters into a byte array.
     *
     * @param   hex         the hex string
     * @return              the hex string decoded into a byte array
     */
    protected byte[] fromHex(String hex) {
        byte[] binary = new byte[hex.length() / 2];
        for (int i = 0; i < binary.length; i++) {
            binary[i] = (byte) Integer.parseInt(hex.substring(2 * i, 2 * i + 2), 16);
        }
        return binary;
    }

    /**
     * Converts a byte array into a hexadecimal string.
     *
     * @param   array       the byte array to convert
     * @return              a length*2 character string encoding the byte array
     */
    protected String toHex(byte[] array) {
        BigInteger bi = new BigInteger(1, array);
        String hex = bi.toString(16);
        int paddingLength = (array.length * 2) - hex.length();
        if (paddingLength > 0) {
            return String.format("%0" + paddingLength + "d", 0) + hex;
        }

        return hex;
    }
}