Mailinglist Archive: opensuse-security (757 mails)

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Re: [suse-security] which cipher for ssh2
  • From: "Kurt Seifried" <listuser@xxxxxxxxxxxx>
  • Date: Thu, 24 Jan 2002 23:10:02 -0700
  • Message-id: <00a601c1a566$ed37f840$6400030a@xxxxxxxxxxxx>
Just to put the numbers into useful terms:

Assume you have one bad-ass computer. Assume it will do a trillion
(1,000,000,000,000) keys/second (nice).
Assume you have to search 50% of the keyspace on average
80 bit key = on average 38,308 YEARS to break.

So you upgrade your computer, let's say it now does a trillion trillion
keys/second (24 zeros).
Assume you have to search 50% of the keyspace on average
80 bit key = on average 1.2 second. EXCELLENT
90 bit key = on average 20.6 minutes. not bad. so people upgade to 90 bit
keys.
112 bit key = 164 years.
160 bit key = 46,343,912,903,694,283 years.
1024 =
5700447535712569468953910422339626882350256782541560669502475937269554661513
8560100427599353883668195433826065408229755726404670476413185721983584043465
9197037569423594829671728507799344387665269701556798848952843855120124119935
5703764368040995282761394929943067804992387977103 years

As you can unless NP=P, or barring some breakthrough in quantum computing
key lengths should stay well ahead of brute force key factoring for some
time.

Nurt Seifried, kurt@xxxxxxxxxxxx
A15B BEE5 B391 B9AD B0EF
AEB0 AD63 0B4E AD56 E574
http://www.seifried.org/security/





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