phc-discussions - Re: [PHC] scripting memory (not so) high

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Message-ID: <20140110122848.GA31197@openwall.com>
Date: Fri, 10 Jan 2014 16:28:48 +0400
From: Solar Designer <solar@...nwall.com>
To: discussions@...sword-hashing.net
Subject: Re: [PHC] scripting memory (not so) high

On Fri, Jan 10, 2014 at 06:19:21AM -0600, Steve Thomas wrote:
> Store every "size^(1/2)"-th state starting with the first and have size^(1/2) of
> temp
> storage.
> 
> Repeat $t_cost+4 times
> {
>     Start at last stored value fill temp storage. Use temp storage and discard.
>     Start at second to last stored value fill temp storage. Use temp storage and
> discard.
>     ...
> }

Oh, indeed.  Thanks.

> I was aiming for least amount of calls to hash functions while keeping it
> memory-hard. I guess I forgot make sure about the last part :).

Yes, these two were my goals too.

Alexander