http://commons.apache.org/proper/commons-codec/: The Apache Commons Codec package contains simple encoder and decoders for various formats such as Base64 and Hexadecimal. In addition to these widely used encoders and decoders, the codec package also maintains a collection of phonetic encoding utilities. (The Apache Software Foundation)
  • Christopher O'Brien
  • Martin Redington
  • Jeffery Dever
  • Steve Zimmermann
  • Benjamin Walstrum
  • Oleg Kalnichevski
  • Dave Dribin
  • Alex Karasulu
  • Matthew Inger
  • Jochen Wiedmann
  • Sebastian Bazley
  • Matthew Pocock
  • Colm Rice 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.commons.codec.digest;

import java.security.SecureRandom;
import java.util.concurrent.ThreadLocalRandom;

import org.apache.commons.codec.Charsets;


GNU libc crypt(3) compatible hash method.

 See crypt(String, String) for further details. 

This class is immutable and thread-safe.

Version:$Id$
Since:1.7
/**
 * GNU libc crypt(3) compatible hash method.
 * <p>
 * See {@link #crypt(String, String)} for further details.
 * <p>
 * This class is immutable and thread-safe.
 *
 * @version $Id$
 * @since 1.7
 */
public class Crypt {

    
Encrypts a password in a crypt(3) compatible way.

 A random salt and the default algorithm (currently SHA-512) are used. See crypt(String, String) for details. 


 A salt is generated for you using ThreadLocalRandom; for more secure salts consider using SecureRandom to generate your own salts and calling crypt(byte[], String). 


Params:
  • keyBytes – 
           plaintext password
Throws:
Returns:hash value
/**
     * Encrypts a password in a crypt(3) compatible way.
     * <p>
     * A random salt and the default algorithm (currently SHA-512) are used. See {@link #crypt(String, String)} for
     * details.
     * </p>
     * <p>
     * A salt is generated for you using {@link ThreadLocalRandom}; for more secure salts consider using
     * {@link SecureRandom} to generate your own salts and calling {@link #crypt(byte[], String)}.
     * </p>
     *
     * @param keyBytes
     *            plaintext password
     * @return hash value
     * @throws IllegalArgumentException
     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
     */
    public static String crypt(final byte[] keyBytes) {
        return crypt(keyBytes, null);
    }

    
Encrypts a password in a crypt(3) compatible way.

 If no salt is provided, a random salt and the default algorithm (currently SHA-512) will be used. See crypt(String, String) for details. 
Params:
  • keyBytes – 
           plaintext password
  • salt –  real salt value without prefix or "rounds=". The salt may be null, in which case a salt is generated for you using ThreadLocalRandom; for more secure salts consider using SecureRandom to generate your own salts.
Throws:
Returns:hash value
/**
     * Encrypts a password in a crypt(3) compatible way.
     * <p>
     * If no salt is provided, a random salt and the default algorithm (currently SHA-512) will be used. See
     * {@link #crypt(String, String)} for details.
     *
     * @param keyBytes
     *            plaintext password
     * @param salt
     *            real salt value without prefix or "rounds=". The salt may be null, in which case a salt is generated for
     *            you using {@link ThreadLocalRandom}; for more secure salts consider using {@link SecureRandom} to
     *            generate your own salts.
     * @return hash value
     * @throws IllegalArgumentException
     *             if the salt does not match the allowed pattern
     * @throws IllegalArgumentException
     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
     */
    public static String crypt(final byte[] keyBytes, final String salt) {
        if (salt == null) {
            return Sha2Crypt.sha512Crypt(keyBytes);
        } else if (salt.startsWith(Sha2Crypt.SHA512_PREFIX)) {
            return Sha2Crypt.sha512Crypt(keyBytes, salt);
        } else if (salt.startsWith(Sha2Crypt.SHA256_PREFIX)) {
            return Sha2Crypt.sha256Crypt(keyBytes, salt);
        } else if (salt.startsWith(Md5Crypt.MD5_PREFIX)) {
            return Md5Crypt.md5Crypt(keyBytes, salt);
        } else {
            return UnixCrypt.crypt(keyBytes, salt);
        }
    }

    
Calculates the digest using the strongest crypt(3) algorithm.


A random salt and the default algorithm (currently SHA-512) are used.



 A salt is generated for you using ThreadLocalRandom; for more secure salts consider using SecureRandom to generate your own salts and calling crypt(String, String). 


Params:
  • key – 
           plaintext password
Throws:
See Also:
Returns:hash value
/**
     * Calculates the digest using the strongest crypt(3) algorithm.
     * <p>
     * A random salt and the default algorithm (currently SHA-512) are used.
     * </p>
     * <p>
     * A salt is generated for you using {@link ThreadLocalRandom}; for more secure salts consider using
     * {@link SecureRandom} to generate your own salts and calling {@link #crypt(String, String)}.
     * </p>
     *
     * @see #crypt(String, String)
     * @param key
     *            plaintext password
     * @return hash value
     * @throws IllegalArgumentException
     *             when a {@link java.security.NoSuchAlgorithmException} is caught.
     */
    public static String crypt(final String key) {
        return crypt(key, null);
    }

    
Encrypts a password in a crypt(3) compatible way.


The exact algorithm depends on the format of the salt string:

    

  • SHA-512 salts start with $6$ and are up to 16 chars long. 
  • SHA-256 salts start with $5$ and are up to 16 chars long 
  • MD5 salts start with $1$ and are up to 8 chars long 
  • DES, the traditional UnixCrypt algorithm is used with only 2 chars

  • Only the first 8 chars of the passwords are used in the DES algorithm!

 The magic strings "$apr1$" and "$2a$" are not recognized by this method as its output should be identical with that of the libc implementation. 
 The rest of the salt string is drawn from the set [a-zA-Z0-9./] and is cut at the maximum length of if a "$" sign is encountered. It is therefore valid to enter a complete hash value as salt to e.g. verify a password with: 
storedPwd.equals(crypt(enteredPwd, storedPwd))



 The resulting string starts with the marker string ($n$), where n is the same as the input salt. The salt is then appended, followed by a "$" sign. This is followed by the actual hash value. For DES the string only contains the salt and actual hash. The total length is dependent on the algorithm used: 
    

  • SHA-512: 106 chars

  • SHA-256: 63 chars

  • MD5: 34 chars

  • DES: 13 chars




Example:

     crypt("secret", "$1$xxxx") => "$1$xxxx$aMkevjfEIpa35Bh3G4bAc."
     crypt("secret", "xx") => "xxWAum7tHdIUw"




This method comes in a variation that accepts a byte[] array to support input strings that are not encoded in
UTF-8 but e.g. in ISO-8859-1 where equal characters result in different byte values.

Params:
  • key – 
           plaintext password as entered by the used
  • salt –  real salt value without prefix or "rounds=". The salt may be null, in which case a salt is generated for you using ThreadLocalRandom; for more secure salts consider using SecureRandom to generate your own salts.
Throws:
See Also:
  • The man page of the libc crypt (3) function.
Returns:hash value, i.e. encrypted password including the salt string
/**
     * Encrypts a password in a crypt(3) compatible way.
     * <p>
     * The exact algorithm depends on the format of the salt string:
     * <ul>
     * <li>SHA-512 salts start with {@code $6$} and are up to 16 chars long.
     * <li>SHA-256 salts start with {@code $5$} and are up to 16 chars long
     * <li>MD5 salts start with {@code $1$} and are up to 8 chars long
     * <li>DES, the traditional UnixCrypt algorithm is used with only 2 chars
     * <li>Only the first 8 chars of the passwords are used in the DES algorithm!
     * </ul>
     * The magic strings {@code "$apr1$"} and {@code "$2a$"} are not recognized by this method as its output should be
     * identical with that of the libc implementation.
     * <p>
     * The rest of the salt string is drawn from the set {@code [a-zA-Z0-9./]} and is cut at the maximum length of if a
     * {@code "$"} sign is encountered. It is therefore valid to enter a complete hash value as salt to e.g. verify a
     * password with:
     *
     * <pre>
     * storedPwd.equals(crypt(enteredPwd, storedPwd))
     * </pre>
     * <p>
     * The resulting string starts with the marker string ({@code $n$}), where n is the same as the input salt.
     * The salt is then appended, followed by a {@code "$"} sign.
     * This is followed by the actual hash value.
     * For DES the string only contains the salt and actual hash.
     * The total length is dependent on the algorithm used:
     * <ul>
     * <li>SHA-512: 106 chars
     * <li>SHA-256: 63 chars
     * <li>MD5: 34 chars
     * <li>DES: 13 chars
     * </ul>
     * <p>
     * Example:
     *
     * <pre>
     *      crypt("secret", "$1$xxxx") =&gt; "$1$xxxx$aMkevjfEIpa35Bh3G4bAc."
     *      crypt("secret", "xx") =&gt; "xxWAum7tHdIUw"
     * </pre>
     * <p>
     * This method comes in a variation that accepts a byte[] array to support input strings that are not encoded in
     * UTF-8 but e.g. in ISO-8859-1 where equal characters result in different byte values.
     *
     * @see "The man page of the libc crypt (3) function."
     * @param key
     *            plaintext password as entered by the used
     * @param salt
     *            real salt value without prefix or "rounds=". The salt may be null, in which case a salt is generated for
     *            you using {@link ThreadLocalRandom}; for more secure salts consider using {@link SecureRandom} to
     *            generate your own salts.
     * @return hash value, i.e. encrypted password including the salt string
     * @throws IllegalArgumentException
     *             if the salt does not match the allowed pattern
     * @throws IllegalArgumentException
     *             when a {@link java.security.NoSuchAlgorithmException} is caught. *
     */
    public static String crypt(final String key, final String salt) {
        return crypt(key.getBytes(Charsets.UTF_8), salt);
    }
}