phc-discussions - Re: [PHC] Another PHC candidates "mechanical" tests (ROUND2)

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Date: Thu, 26 Mar 2015 12:29:47 +0300
From: Solar Designer <solar@...nwall.com>
To: discussions@...sword-hashing.net
Subject: Re: [PHC] Another PHC candidates "mechanical" tests (ROUND2)

On Thu, Mar 26, 2015 at 08:11:52AM +0100, Milan Broz wrote:
> I would ask another way - there is already some clone of LUKS support
> in Grub2 bootloader (but take is just an example).
> 
> Are the algorithms easily portable without major changes to such environment
> including parallel attributes (no problem if it is run sequentially there)?

Yes, you should be able to build without multi-threading support yet be
able to compute parallelism-enabled derived keys (sequentially).

> It is not major user case (most of Linux distributions uses non-encrypted
> inittramdisk and unlock system device from fully running OS environment.
> But I do not want to close this way for the future.

Makes sense.

> Or more generic question: what about embedded world?
> 
> PHC seems to be mainly about online services, where you have some big
> Intel server hosting behind it but I would like to not forget about embedded
> systems.

You simply scale down the cost settings accordingly.  yescrypt is
designed to achieve decent attack resistance even at low settings (of
course, I mean decent for those settings), including below 1 MB.

Alternatively, there are PHC finalists that are well-suited specifically
for such uses - that's Pufferfish and maybe POMELO - but yescrypt has
the advantage of being a single scheme that is well-suited across the
range from KBs to TBs (and beyond, when relevant).

Lyra2 is less suitable for low sizes like this.

> If not embedded, even low-cost Raspberry PI2 have 4 cores
> (and Neon engine capable accelerate e.g. AES).
> (Actually I should run tests there as well perhaps :-)
> 
> And yes, people are often using FDE on these platforms.
> 
> Moreover Android: it uses dmcrypt but do not utilize LUKS but has similar
> key storage which uses PBKDF2 replaced by scrypt (since 4.4) AFAIK.

yescrypt should work well on those platforms, and adding NEON intrinsics
is planned.  The specific SIMD operations have been chosen such that
they're available on NEON too (not only on SSE*/AVX*).

Alexander