Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 23 Oct 2015 17:56:31 +0300
Subject: Re: Prime example of a can of worms

On 2015-10-21 22:27:33 -0600, Kurt Seifried wrote:

 > I can't even begin to think how slow this would be on hardware
 > limited systems like $20 routers and whatnot (in theory you could
 > have systems taking tens of minutes), which would not be popular
 > with consumers (turn the unit on and wait from 0 seconds to an
 > hour or so for the web interface to come up!).

Normally, all those $20 (or even $10) routers don't need to generate
keys at the first start - they are configured via plain HTTP given
that user's PC is connected to a "LAN" port with a cable. And only
when user activates the outside access (via VPN or SSH) the keys are
to be generated - possibly in several hours, like those 17 hours the
`openssh dhparam -5 8192` command took at my notebook :-)

 > With this data in mind I think we need to generally encourage
 > everyone to go to a minimum of 2048 bit primes

For my clients, I force the use of 4096 bit for over 5 years.

 > (which should last a few more years assuming quantum computers
 > don't suddenly make factorization easy)

That wouldn't be suddenly. At least I'm not going to worry until
they would be able to factorize some number close to 2^160 - say,
266508845991748914569771929356540352347893240569. And yes, I know
one divisor: it is 4458192223320340849 :-)

 > and establish some safe methods of creating them, much like
 > generating CA encryption keys we need to ensure the systems/
 > software in use are correct, the entropy is available (and
 > not manipulated) and so on.

Here we come to trusted execution, trusted computation and so on.

 > Ideally we'd like to see people using different primes (e.g.
 > hardware manufacturers not using the same primes as everyone
 > else) and where possible people needing more security (e.g. a
 > VPN hosting provider) should generate their own keys securely.

Theory is fine. But in practice we see weakened algorithms with
(intentionally?) reduced key size.

Alexey V. Vissarionov aka Gremlin from Kremlin <gremlin ПРИ gremlin ТЧК ru>
GPG: 8832FE9FA791F7968AC96E4E909DAC45EF3B1FA8 @ hkp://

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.