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Re: [Cfrg] Analysis of ipcrypt?

Daniel Kahn Gillmor <dkg@fifthhorseman.net> Fri, 23 February 2018 00:07 UTC

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From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
To: Greg Rose <ggr@seer-grog.net>, "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Samuel Neves <sneves@dei.uc.pt>, Paul Hoffman <paul.hoffman@icann.org>, "cfrg@irtf.org" <cfrg@irtf.org>
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Date: Thu, 22 Feb 2018 16:06:22 -0800
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Subject: Re: [Cfrg] Analysis of ipcrypt?
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On Thu 2018-02-22 06:11:38 -0800, Greg Rose wrote:
> I cooked up "skip32" for a similar purpose a decade or two ago. It's
> based on Skipjack. Googling for it just now, it appears to be the most
> widely-deployed cipher I worked on... lots of implementations.

yeah, skip32 is available all over the place, but...

> void
> skip32(BYTE key[10], BYTE buf[4], int encrypt)

80-bit keys don't seem appropriate for modern use, even for a 32-bit
format-preserving encryption (FPE) cipher.

NIST SP.800-38G identifies FF1 and FF3 as FPE options, both based on AES
with 128-bit or larger keys.

     --dkg

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