Access the raw PBKDF2 output

[LoonyPandora]

The module Crypt::PBKDF2 Provides methods to get at the hash in binary, base64, and hex encoded versions of the hash. Is it possible to provide methods to access these from within Digest::PBKDF2 ?

This would make it consistent with other modules in the Digest:: namespace, such as Digest::SHA which provides the following methods.

$digest = $sha->digest; 
$digest = $sha->hexdigest;
$digest = $sha->b64digest;

[amiri]

Seems like it could be done. Would you like to make a patch?

[LoonyPandora]

Not a problem, I can write up a patch over the weekend.

However, to be properly consistent with the other modules in the Digest:: namespace, I think the output of digest() should be changed to contain just the hash, and not the ldap / crypt representation.

I'd then like to add two new methods to access the ldpap / crypt representation (as_ldap() and as_crypt() perhaps?)

Obviously this would break backwards compatibility, but it would make this module function the same as every other Digest:: module - which I think is important.

Does this sound reasonable to you?

[amiri]

I don't like breaking back-compat. You can switch formats if you like right now:

my $digester = Digest::PBKDF2->new(encoding => 'ldap');

I like consistency, too, but is that the only reason to change the API?

[amiri]

I'm not rejecting the idea, but I would like to know whether there are other reasons.

[LoonyPandora]

It's not about changing the default format from crypt -> ldap. It's
that neither format is what is output by other Digest modules.

Consider if you use this module indirectly, like my $digest = Digest->new('PBKDF2'); if you call digest on that object, you
don't get the digest, you get the digest / salt / bunch of other stuff
too, in either a crypt or ldap representation. Every other digest
module returns just the digest on that method call. If I create a
b64digest method for this module to base 64 encode the raw digest,
one would expect base 64 encoding the output of digest would
produce the same output - but since digest has all the extra stuff
in it, it wouldn't work.

There is a benchmarking script in the Task::Digest module, if you
examine that you can see how all the modules output just the digest
when the digest method is called.

The reason I ask this is because I maintain a module that gives
developers the option to pick their hashing method for passwords, and
it relies on all digest modules following the same spec. If this
module outputs something other than the raw digest, then I can't use
it, sadly.

I understand breaking backwards compatibility is a big deal, that's
why I wanted to discuss it. However i think consistency with all the
other modules is worth it.

In the end it's your module, you have the final say, thanks for your time :)

Please excuse my brevity,
Sent from my iPhone

On 1 Apr 2012, at 06:16, Amiri Barksdale
reply@reply.github.com
wrote:

I don't like breaking back-compat. You can switch formats if you like right now:

my $digester = Digest::PBKDF2->new(encoding => 'ldap');

I like consistency, too, but is that the only reason to change the API?

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[amiri]

That wasn't brief at all. Thank you for the explanation! OK, let's do it.