oss-sec mailing list archives
Re: Prime example of a can of worms
From: Florent Daigniere <florent.daigniere () trustmatta com>
Date: Thu, 22 Oct 2015 10:01:33 +0200
On Wed, 2015-10-21 at 23:09 -0600, Kurt Seifried wrote:
On Wed, Oct 21, 2015 at 10:45 PM, Joshua Rogers <oss () internot info> wrote:On 22/10/15 15:27, Kurt Seifried wrote:Ideally we'd like to see people using different primes (e.g. hardware manufacturers notusingthe same primes as everyone else) and where possible people needing more security (e.g. a VPN hosting provider) should generate their own keys securely.Could it be possible to generate a new prime in the background, and when it has been generated, on the next reboot use that one instead? And if there is not enough time for the new prime to be generated, it falls back to the old one? I agree that manufacturers should be using a different prime per, at least, batch of products.My fear would be device makers getting it horribly wrong on the devices in question. E.g.: http://www.theregister.co.uk/2015/10/21/german_govt_mulls_security_te sts_of_sohopeless_routers/ Having a large pool of known good primes would be easier for them to use I suspect. Sadly we can't let perfect be the enemy of the good, or in this case the "not completely terrible".
I still don't get why people are pushing for "non-standard" groups. What you need is a good security margin... No one should be using 1024bit DH groups anymore and 2048 bit groups should have disappeared *before* ~2020 http://www.keylength.com/en/3/ If we want PFS to work in practice we need "auditable" deployments... and that won't be possible with custom DH groups (verifying the security/suitability of a group is non-straightforward as the rest of the thread has pointed out). Really, what are we after here? - Preventing pre-computation? Pick a larger group. - Avoiding "massive" problems in case the standardized groups do turn out to be unsuitable (sub-groups, ...)? - Something else? Florent
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Current thread:
- Re: Prime example of a can of worms, (continued)
- Re: Prime example of a can of worms Daniel Kahn Gillmor (Oct 19)
- Re: Prime example of a can of worms Kurt Seifried (Oct 19)
- Re: Prime example of a can of worms Daniel Kahn Gillmor (Oct 19)
- Re: Prime example of a can of worms Brad Knowles (Oct 20)
- Re: Prime example of a can of worms Kurt Seifried (Oct 20)
- Re: Prime example of a can of worms gremlin (Oct 20)
- Re: Prime example of a can of worms Matthias Weckbecker (Oct 21)
- Re: Prime example of a can of worms Kurt Seifried (Oct 21)
- Re: Prime example of a can of worms Joshua Rogers (Oct 21)
- Re: Prime example of a can of worms Kurt Seifried (Oct 21)
- Re: Prime example of a can of worms Florent Daigniere (Oct 22)
- Re: Prime example of a can of worms Daniel Kahn Gillmor (Oct 22)
- Re: Prime example of a can of worms Kurt Seifried (Oct 22)
- Re: Prime example of a can of worms Daniel Kahn Gillmor (Oct 22)
- Re: Prime example of a can of worms gremlin (Oct 23)