NAME
    PBKDF2::Tiny - Minimalist PBKDF2 (RFC 2898) with HMAC-SHA1 or HMAC-SHA2

VERSION
    version 0.002

SYNOPSIS
        use PBKDF2::Tiny qw/derive verify/;

        my $dk = derive( 'SHA-1', $pass, $salt, $iters );

        if ( verify( $dk, 'SHA-1', $pass, $salt, $iters ) ) {
            # password is correct
        }

DESCRIPTION
    This module provides an RFC 2898 <https://tools.ietf.org/html/rfc2898>
    compliant PBKDF2 implementation using HMAC-SHA1 or HMAC-SHA2 in under
    100 lines of code. If you are using Perl 5.10 or later, it uses only
    core Perl modules. If you are on an earlier version of Perl, you need
    Digest::SHA or Digest::SHA::PurePerl.

FUNCTIONS
  derive
        $dk = derive( $type, $password, $salt, $iterations, $dk_length )

    The "derive" function outputs a binary string with the derived key. The
    first argument indicates the digest function to use. It must be one of:
    SHA-1, SHA-224, SHA-256, SHA-384, or SHA-512.

    If a password or salt are not provided, they default to the empty
    string, so don't do that! RFC 2898 recommends
    <https://tools.ietf.org/html/rfc2898#section-4.1> a random salt of at
    least 8 octets. If you need a cryptographically strong salt, consider
    Crypt::URandom.

    The number of iterations defaults to 1000 if not provided. If the
    derived key length is not provided, it defaults to the output size of
    the digest function.

  derive_hex
    Works just like "derive" but outputs a hex string.

  verify
        $bool = verify( $dk, $type, $password, $salt, $iterations, $dk_length );

    The "verify" function checks that a given derived key (in binary form)
    matches the password and other parameters provided using a constant-time
    comparison function.

    The first parameter is the derived key to check. The remaining
    parameters are the same as for "derive".

  verify_hex
    Works just like "verify" but the derived key must be a hex string
    (without a leading "0x").

  digest_fcn
        ($fcn, $block_size, $digest_length) = digest_fcn('SHA-1');
        $digest = $fcn->($data);

    This function is used internally by PBKDF2::Tiny, but made available in
    case it's useful to someone.

    Given one of the valid digest types, it returns a function reference
    that digests a string of data. It also returns block size and digest
    length for that digest type.

  hmac
        $key = $digest_fcn->($key) if length($key) > $block_sizes;
        $hmac = hmac( $data, $key, $digest_fcn, $block_size );

    This function is used internally by PBKDF2::Tiny, but made available in
    case it's useful to someone.

    The first two arguments are the data and key inputs to the HMAC
    function. Note: if the key is longer than the digest block size, it must
    be preprocessed using the digesting function.

    The third and fourth arguments must be a digesting code reference (from
    "digest_fcn") and block size.

SEE ALSO
    *   Crypt::PBKDF2

    *   Digest::PBDKF2

SUPPORT
  Bugs / Feature Requests
    Please report any bugs or feature requests through the issue tracker at
    <https://github.com/dagolden/PBKDF2-Tiny/issues>. You will be notified
    automatically of any progress on your issue.

  Source Code
    This is open source software. The code repository is available for
    public review and contribution under the terms of the license.

    <https://github.com/dagolden/PBKDF2-Tiny>

      git clone https://github.com/dagolden/PBKDF2-Tiny.git

AUTHOR
    David Golden <dagolden@cpan.org>

COPYRIGHT AND LICENSE
    This software is Copyright (c) 2014 by David Golden.

    This is free software, licensed under:

      The Apache License, Version 2.0, January 2004

