[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20241020210151.GA4176@openwall.com>
Date: Sun, 20 Oct 2024 23:01:51 +0200
From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com
Subject: Re: older Intel Quick Assist (QAT) performance boost?
On Sun, Oct 20, 2024 at 12:17:46PM -0500, David Sutherland wrote:
> Any thoughts on using now relatively inexpensive ($50 - $120) Intel Quick
> Assist cards like the 8950, 8970 to accelerate some hashing functions?
Yes. They look pretty useless for this purpose.
> Could that improve JTR performance?
The short answer is no.
Longer answer is any extra compute device could help a little bit if
used along with what you already had, but this is not worth it.
For hashes and symmetric ciphers, there's no point because apparently no
relevant higher-level algorithm (such as PBKDF2) is implemented on
device (maybe can be done with a firmware hack?) and without that we'd
just bump into bandwidth to/from the card.
As I could find, these cards can do 100K 2048-bit RSA key decrypts per
second. This is pretty good, but not that impressive. ECC algorithms
are mentioned as supported, but no speed info given - I guess it's
"similar". When these algorithms are needed in password cracking, they
are typically part of the final verification step, after slow key
derivation, so their performance has only moderate overall effect.
The 8970 card can apparently do up to 160 Gbps deflate. We could
theoretically use that in the few cases where we have to decompress data
before we're able to reject a candidate password.
Overall, performance is good enough for the intended purpose - to
off-load cryptographic processing and (de)compression from CPU to
device, potentially saturating a 100 Gbps NIC. However, if your task is
local cryptographic processing not involving network, the point is moot.
You wouldn't achieve more than a 2x speedup (over CPUs) in this way (not
with one card at least), so you're better off using those slots for
GPUs. Not to mention that we have no support for these cards at all,
and aren't planning to add any.
Alexander
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
