> ---------- Forwarded message ---------- > From: "Robert J. Hansen" <r...@sixdemonbag.org> > To: Jerome Baum <jerome+per...@jeromebaum.com>, gnupg-users@gnupg.org > Date: Tue, 11 Oct 2011 08:27:47 -0400 > Subject: Re: Why revoke a key? > On 10/10/2011 5:44 PM, Jerome Baum wrote: >> But remember Murphy's(?) law! -- (I mean the one about doubling computer >> power every 18 months -- are there two Murphy's laws? Confused now...) > > Moore's Law. > > For reference, a 40-bit key is breakable today by just about anyone, a > 64-bit key is breakable today by people with access to significant > computational resources (hundreds of machines), and it's plausible to > believe fantastically wealthy adversaries can break 80-bit keys. > > In 1998, EFF's DEEP CRACK exhausted a 56-bit keyspace in roughly 24 > hours at a cost of $250,000. Assuming Moore's Law holds true, that > means it could be built today with equivalent performance for about $1,000. > > A 64-bit keyspace is only a factor of 250 harder: a DEEP CRACK/64 could > theoretically be made at a cost of $250,000. An 80-bit keyspace is a > factor of 50,000 harder, more or less, putting the price of that at $12 > billion, somewhere in there. > > This is really rough back-of-the-envelope calculation, but it passes my > sniff test.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Somewhat outdated, but here is a webpage that makes some comparisons. They don't give the bitsize of the keys, just the number of combinations, but it is still representative. <http://www.lockdown.co.uk/?pg=combi> Some other interesting, but likely outdated, discussions: <http://news.electricalchemy.net/2009/10/password-cracking-in- cloud-part-5.html> <http://news.electricalchemy.net/2009/10/cracking-passwords-in- cloud.html> <-- discusses PGP Avi -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) - GPGshell v3.77 Comment: Most recent key: Click show in box @ http://is.gd/4xJrs iJgEAREKAEAFAk6UWfc5GGh0dHA6Ly9wZ3AubmljLmFkLmpwL3Brcy9sb29rdXA/ b3A9Z2V0JnNlYXJjaD0weEY4MEUyOUY5AAoJEA1isBn4Din5gXcBAJhFPQdzW6Xm +yGodASC7eBNvkyE67/eHZZK+xLWe+faAP4ghpRCy6ryU8F0Yz65JmzEmmpyFGKw vuJ2Oxoq7UTO+g== =Fdds -----END PGP SIGNATURE----- ---- User:Avraham pub 3072D/F80E29F9 1/30/2009 Avi (Wikimedia-related key) <avi.w...@gmail.com> Primary key fingerprint: 167C 063F 7981 A1F6 71EC ABAA 0D62 B019 F80E 29F9 _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users
