Full Disclosure mailing list archives
Re: Does this exist ?
From: Andrew Farmer <andfarm () gmail com>
Date: Thu, 5 Jul 2007 15:05:05 -0700
On 05 Jul 07, at 06:20, Dan Becker wrote:
I have an idea that won't leave me alone and this list seems to have the most potential for knowing if the idea exists. My apologies for a somewhat offtopic post. Would there be a way to create a rainbow table of tcp packets to be used to generate one packet for every 1000 or so normal packets simply by matching hashes with databases on both ends ?
No; for a 128-bit hash (for example) there are only 2^128 packets which can be uniquely represented. This is far below the 2^12144 1518- byte packets which are possible, so - by the pigeonhole principle, there will be collisions. Increasing the hash size won't help unless you make it at least as large as the packet, at which point you aren't gaining anything. Computing such a rainbow table is computationally impossible, anyway. The largest keyspace which I know of that's been brute-forced was somewhere around 64 bits, and that takes either dedicated hardware or a distributed-computing network. 128 bits is believed to be physically impossible, and even that is just barely enough to fit a TCP header into, without any data. If the data being transmitted over the link is reasonably redundant, then you might get lucky and be able to just hash the relevant packets ahead of time. However, you could probably do even better with a purpose-built compression scheme anyway. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- Does this exist ? Dan Becker (Jul 05)
- Re: Does this exist ? J.A. Terranson (Jul 05)
- Re: Does this exist ? Andrew Farmer (Jul 05)
- Re: Does this exist ? Dan Becker (Jul 06)
- Re: Does this exist ? Fionnbharr (Jul 06)
- Re: Does this exist ? Matjaz Debelak (Jul 06)
- Re: Does this exist ? frode (Jul 06)
- Message not available
- Re: Does this exist ? Rob McCauley (Jul 06)
- Re: Does this exist ? Dan Becker (Jul 06)
- Re: Does this exist ? Dan Becker (Jul 06)
- Re: Does this exist ? Dan Becker (Jul 12)
- Re: Does this exist ? Valdis . Kletnieks (Jul 12)
- Re: Does this exist ? Dan Becker (Jul 12)