[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: A little social engineering
At 10:24 AM 6/21/97 -0400, Rodney Thayer wrote:
>Some more data points to consider:
>
>- there's no RC5 hardware or CAST-128 hardware, as far as I know [ok, chip
>makers, crawl out of the woodwork now and correct me, then send me samples
>:-)]
[Me too!] However, at least for me, 16 round RC5 (independent of
keysize) is about twice as fast than CAST-128 in software. (FWIW: I
get 30.5 megabits/second with RC5-R16-B128 and 16.9 megabits/second with
CAST5-128 with both implementations written in C, compiled with GNU C
2.7.2.2 under NetBSD/i386 1.2G on a Pentium-133. An Alpha EV5-266 will
do RC5 @ ~100 megabits per second).
>- there is "running code" for 3DES, CAST-128 and ARCFOUR, that I know of.
And RC5 (Why does isakmp-oakley-03 use RC5-R12-B64 instead of
RC5-R16-B128.)?
>- there's no ESP docs for IDEA, present or on the radar.
I've thought of writing one but it hasn't been high on my list
of things I might do. Given the availability of CAST5-128 and/or
Blowfish, I don't see a pressing need for IDEA given that it's
restrictions. [Of course, one could say the same of RC5.]
>- there seems to be debate on whether or not 3DES is "slow".
3DES is slow compared to ciphers of equivalent length (CAST, RC5).
(6.22 megabits/sec (as stated by Phil Karn) .vs. the numbers I quoted
above).
>- what's wrong with "recommending you implement at least two ciphers" for
>the moment?
I would make that DES and at least one other cipher.
>In some sense we were using DES because "it had been thoroughly analyzed".
"Better the devil you know..."
>Subjectively I think 3DES and CAST-128 are the ones to look at since (a)
>there's code, (b) there's hardware and (c) there's a low volume of negative
>cryptographic opinion on them.
At least in my brief search, I didn't find a CAST-128 implementation
but it didn't take that long to write one using RFC 2144. CAST-128 may
be too new to have much analysis done yet. I like it but it may be
premature.
--
Matt Thomas Internet: matt.thomas@altavista-software.com
Internet Locksmith WWW URL: <coming eventually>
AltaVista Internet Software Disclaimer: This message reflects my own
Littleton, MA warped views, etc.
Follow-Ups:
References: