# Class Md5Crypt

java.lang.Object
org.apache.commons.codec.digest.Md5Crypt

public class Md5Crypt extends Object
The libc crypt() "$1$" and Apache "$apr1$" MD5-based hash algorithm.

Based on the public domain ("beer-ware") C implementation from Poul-Henning Kamp which was found at: crypt-md5.c @ freebsd.org

Source:

    $FreeBSD: src/lib/libcrypt/crypt-md5.c,v 1.1 1999/01/21 13:50:09 brandon Exp $

Conversion to Kotlin and from there to Java in 2012.

The C style comments are from the original C code, the ones with "//" from the port.

This class is immutable and thread-safe.

Since:
  1.7

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Md5Crypt()`
  Deprecated.
  TODO Make private in 2.0.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static String`
  `apr1Crypt(byte[] keyBytes)`
  See `apr1Crypt(byte[], String)` for details.
  `static String`
  `apr1Crypt(byte[] keyBytes, String salt)`
  See `apr1Crypt(String, String)` for details.
  `static String`
  `apr1Crypt(byte[] keyBytes, Random random)`
  See `apr1Crypt(byte[], String)` for details.
  `static String`
  `apr1Crypt(String keyBytes)`
  See `apr1Crypt(String, String)` for details.
  `static String`
  `apr1Crypt(String keyBytes, String salt)`
  Generates an Apache htpasswd compatible "$apr1$" MD5 based hash value.
  `static String`
  `md5Crypt(byte[] keyBytes)`
  Generates a libc6 crypt() compatible "$1$" hash value.
  `static String`
  `md5Crypt(byte[] keyBytes, String salt)`
  Generates a libc crypt() compatible "$1$" MD5 based hash value.
  `static String`
  `md5Crypt(byte[] keyBytes, String salt, String prefix)`
  Generates a libc6 crypt() "$1$" or Apache htpasswd "$apr1$" hash value.
  `static String`
  `md5Crypt(byte[] keyBytes, String salt, String prefix, Random random)`
  Generates a libc6 crypt() "$1$" or Apache htpasswd "$apr1$" hash value.
  `static String`
  `md5Crypt(byte[] keyBytes, Random random)`
  Generates a libc6 crypt() compatible "$1$" hash value.

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### Md5Crypt

    @Deprecated public Md5Crypt()
    Deprecated.
    TODO Make private in 2.0.
    TODO Make private in 2.0.

- ## Method Details

  - ### apr1Crypt

    public static String apr1Crypt(byte[] keyBytes)
    See `apr1Crypt(byte[], String)` for details.

    A salt is generated for you using `SecureRandom`; your own `Random` in `apr1Crypt(byte[], Random)`.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.
    See Also:
      - `apr1Crypt(byte[], String)`

  - ### apr1Crypt

    public static String apr1Crypt(byte[] keyBytes, Random random)
    See `apr1Crypt(byte[], String)` for details.

    A salt is generated for you using the user provided `Random`.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
      `random` - the instance of `Random` to use for generating the salt. Consider using `SecureRandom` for more secure salts.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.
    Since:
      1.12
    See Also:
      - `apr1Crypt(byte[], String)`

  - ### apr1Crypt

    public static String apr1Crypt(byte[] keyBytes, String salt)
    See `apr1Crypt(String, String)` for details.

    A salt is generated for you using `SecureRandom`

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
      `salt` - An APR1 salt. The salt may be null, in which case a salt is generated for you using `SecureRandom`.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - if the salt does not match the allowed pattern.
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.

  - ### apr1Crypt

    public static String apr1Crypt(String keyBytes)
    See `apr1Crypt(String, String)` for details.

    A salt is generated for you using `SecureRandom`.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.
    See Also:
      - `apr1Crypt(byte[], String)`

  - ### apr1Crypt

    public static String apr1Crypt(String keyBytes, String salt)
    Generates an Apache htpasswd compatible "$apr1$" MD5 based hash value.

    The algorithm is identical to the crypt(3) "$1$" one but produces different outputs due to the different salt prefix.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
      `salt` - salt string including the prefix and optionally garbage at the end. The salt may be null, in which case a salt is generated for you using `SecureRandom`.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - if the salt does not match the allowed pattern.
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.

  - ### md5Crypt

    public static String md5Crypt(byte[] keyBytes)
    Generates a libc6 crypt() compatible "$1$" hash value.

    See `md5Crypt(byte[], String)` for details.

    A salt is generated for you using `SecureRandom`.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.
    See Also:
      - `md5Crypt(byte[], String)`

  - ### md5Crypt

    public static String md5Crypt(byte[] keyBytes, Random random)
    Generates a libc6 crypt() compatible "$1$" hash value.

    See `md5Crypt(byte[], String)` for details.

    A salt is generated for you using the instance of `Random` you supply.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
      `random` - the instance of `Random` to use for generating the salt. Consider using `SecureRandom` for more secure salts.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.
    Since:
      1.12
    See Also:
      - `md5Crypt(byte[], String)`

  - ### md5Crypt

    public static String md5Crypt(byte[] keyBytes, String salt)
    Generates a libc crypt() compatible "$1$" MD5 based hash value.

    See `Crypt.crypt(String, String)` for details. We use `SecureRandom` for seed generation by default.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
      `salt` - salt string including the prefix and optionally garbage at the end. The salt may be null, in which case a salt is generated for you using `SecureRandom`.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - if the salt does not match the allowed pattern.
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.

  - ### md5Crypt

    public static String md5Crypt(byte[] keyBytes, String salt, String prefix)
    Generates a libc6 crypt() "$1$" or Apache htpasswd "$apr1$" hash value.

    See `Crypt.crypt(String, String)` or `apr1Crypt(String, String)` for details. We use `by default`.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
      `salt` - real salt value without prefix or "rounds=". The salt may be null, in which case a salt is generated for you using `SecureRandom`.
      `prefix` - The salt prefix "$apr1$", "$1$".
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - if the salt does not match the allowed pattern.
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.

  - ### md5Crypt

    public static String md5Crypt(byte[] keyBytes, String salt, String prefix, Random random)
    Generates a libc6 crypt() "$1$" or Apache htpasswd "$apr1$" hash value.

    See `Crypt.crypt(String, String)` or `apr1Crypt(String, String)` for details.

    Parameters:
      `keyBytes` - plaintext string to hash. Each array element is set to `0` before returning.
      `salt` - real salt value without prefix or "rounds=". The salt may be null, in which case a salt is generated for you using `SecureRandom`.
      `prefix` - The salt prefix "$apr1$", "$1$".
      `random` - the instance of `Random` to use for generating the salt. Consider using `SecureRandom` for more secure salts.
    Returns:
      the hash value.
    Throws:
      `IllegalArgumentException` - if the salt or prefix does not match the allowed pattern.
      `IllegalArgumentException` - when a `NoSuchAlgorithmException` is caught.
    Since:
      1.12