File::KDBX::KDF(3p)

NAME
File::KDBX::KDF - A key derivation function

VERSION
version 0.906

DESCRIPTION
A KDF (key derivation function) is used in the transformation of a master key (i.e. one or more component keys) to produce the final encryption key protecting a KDBX database. The File::KDBX distribution comes with several pre-registered KDFs ready to go:

•   "C9D9F39A-628A-4460-BF74-0D08C18A4FEA" - AES

•   "7C02BB82-79A7-4AC0-927D-114A00648238" - AES (challenge-response variant)

•   "EF636DDF-8C29-444B-91F7-A9A403E30A0C" - Argon2d

•   "9E298B19-56DB-4773-B23D-FC3EC6F0A1E6" - Argon2id

NOTE: If you want your KDBX file to be readable by other KeePass implementations, you must use a UUID and algorithm that they support. From the list above, all are well-supported except the AES challenge-response variant which is kind of a pseudo KDF and isn't usually written into files. All of these are good. AES has a longer track record, but Argon2 has better ASIC resistance.

You can also "register" your own KDF. Here is a skeleton:

    package File::KDBX::KDF::MyKDF;

    use parent 'File::KDBX::KDF';

    File::KDBX::KDF->register(
        # $uuid, $package, %args
        "\x12\x34\x56\x78\x9a\xbc\xde\xfg\x12\x34\x56\x78\x9a\xbc\xde\xfg" => __PACKAGE__,
    );

    sub init { ... } # optional

    sub _transform { my ($key) = @_; ... }

ATTRIBUTES

  uuid
    $uuid => $kdf->uuid;

Get the UUID used to determine which function to use.

  seed
    $seed = $kdf->seed;

Get the seed (or salt, depending on the function).

METHODS

  new
    $kdf = File::KDBX::KDF->new(parameters => \%params);

Construct a new KDF.

  init
    $kdf = $kdf->init(%attributes);

Called by "new" to set attributes. You normally shouldn't call this. Returns itself to allow method chaining.

  transform
    $transformed_key = $kdf->transform($key);
    $transformed_key = $kdf->transform($key, $challenge);

Transform a key. The input key can be either a File::KDBX::Key or a raw binary key, and the transformed key will be a raw key.

This can take awhile, depending on the KDF parameters.

If a challenge is provided (and the KDF is AES except for the KeePassXC variant), it will be passed to the key so challenge-response keys can produce raw keys. See "raw_key" in File::KDBX::Key.

  randomize_seed
    $kdf->randomize_seed;

Generate and set a new random seed/salt.

  register
    File::KDBX::KDF->register($uuid => $package, %args);

Register a KDF. Registered KDFs can be used to encrypt and decrypt KDBX databases. A KDF's UUID must be unique and musn't change. A KDF UUID is written into each KDBX file and the associated KDF must be registered with the same UUID in order to decrypt the KDBX file.

$package should be a Perl package relative to "File::KDBX::KDF::" or prefixed with a "+" if it is a fully-qualified package. %args are passed as-is to the KDF's "init" method.

  unregister
    File::KDBX::KDF->unregister($uuid);

Unregister a KDF. Unregistered KDFs can no longer be used to encrypt and decrypt KDBX databases, until reregistered (see "register").

BUGS
Please report any bugs or feature requests on the bugtracker website <https://github.com/chazmcgarvey/File-KDBX/issues>

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

AUTHOR
Charles McGarvey <ccm@cpan.org>

COPYRIGHT AND LICENSE
This software is copyright (c) 2022 by Charles McGarvey.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.