Re: scrypt Internet Draft

[Simon Josefsson <simon@josefsson.org>]

Nick Galbreath <nickg@client9.com> writes:

> Hi team-scrypt!
>
> I'll read  the spec more carefully once I'm back home, but quickly...
>
> Is there a spec for the crypt function/command line format?  Oddly the
> best spec I've seen is the PHP function by the same name.
>
> http://php.net/manual/en/function.crypt.php
>
> FreeBSD has some details as well
> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/crypt.html
>
> and Ulrich Drepper's crypt sha-256/sha-512 impl:
> http://www.akkadia.org/drepper/SHA-crypt.txt
>
> Ideally I'd like a crypt-like format e.g. such as $7$... that
> represents scrypt with related parameters.  Given that Ulrich Drepper
> just wrote a txt file, and didn't appear to submit to an official
> standards body, I suspect that there is no standard.

That is right, I don't think there is any standard, just well
established practice.

> Any tips here, or possibility of adding an appendix to this spec
> documenting a crypt-style format?  Or is this done, and I'm just not
> seeing it?

I agree it should be done, but I'm not convinced it should be done in
this document -- a scrypt-based crypt is not implemented today and would
be experimental, and that will set back the review process of the draft.
Granted, the ASN.1 parts or not implemented either, but I suspect that
more easily will fly under the radar.

We could start it as a parallel effort though.  Would you like to help
work on this?  I started a document here:

https://www.gitorious.org/scrypt/scrypt/blobs/master/unix-scrypt.txt

I think we need implementation experience to move forward, I don't see
much more that is needed in a crypt spec for scrypt.  Maybe some default
parameter suggestions.

/Simon

> thanks
>
> Nick Galbreath
> nickg
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> On Mon, Sep 17, 2012 at 8:18 PM, Colin Percival <cperciva@tarsnap.com> wrote:
>> Hi all,
>>
>> In case anyone here is interested in standards processes, you should be
>> aware that Simon Josefsson has written up scrypt as an Internet Draft
>> which will hopefully end up turning into an RFC:
>>   http://tools.ietf.org/html/draft-josefsson-scrypt-kdf-00
>>
>> --
>> Colin Percival
>> Security Officer Emeritus, FreeBSD | The power to serve
>> Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid