[19617] in cryptography@c2.net mail archive
Re: long-term GPG signing key
daemon@ATHENA.MIT.EDU (Ian G)
Fri Jan 13 11:04:30 2006
X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Fri, 13 Jan 2006 15:32:52 +0000
From: Ian G <iang@systemics.com>
To: Alexander Klimov <alserkli@inbox.ru>
Cc: cryptography@metzdowd.com
In-Reply-To: <TheMailAgent.1956643487522fa@3b19ff06887fa65e6f347>
Alexander Klimov wrote:
> On Wed, 11 Jan 2006, Ian G wrote:
>
>
>>Even though triple-DES is still considered to have avoided that
>>trap, its relatively small block size means you can now put the
>>entire decrypt table on a dvd (or somesuch, I forget the maths).
>
>
> This would need 8 x 2^{64} bytes of storage which is approximately
> 2,000,000,000 DVD's (~ 4 x 2^{32} bytes on each).
>
> Probably, you are referring to the fact that during encryption of a
> whole DVD, say, in CBC mode two blocks are likely to be the same
> since there are an order of 2^{32} x 2^{32} pairs.
Thanks for the correction, yes, so obviously I
muffed that one. I saw it mentioned on this list
about a year ago, but didn't pay enough attention
to recall the precise difficulty that the small
block size of 8 bytes now has.
A few calculations here - even blueray disks won't
help me out.
iang
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