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On Sep 5, 2013, at 6:16 PM, Dan McDonald <dan...@kebe.com> wrote: > Consider the Suite B set of algorithms: > > AES-GCM > AES-GMAC > IEEE Elliptic Curves (256, 384, and 521-bit) > > Traditionally, people were pretty confident in these. How are people's > confidence in them now? My opinion about GCM and GMAC has not changed. I've never been a fan. My objection to them is that they are tetchy to use -- hard to get right, easy to get wrong. It's pretty much what is in Niels's paper: <http://csrc.nist.gov/groups/ST/toolkit/BCM/documents/comments/CWC-GCM/Ferguson2.pdf> I don't think they're actively bad, though. For the purpose they were created for -- parallelizable authenticated encryption -- it serves its purpose. You can have a decent implementor implement them right in hardware and walk away. I think that any of OCB, CCM, or EAX are preferable from a security standpoint, but none of them parallelize as well. If you want to do a lot of encrypted and authenticated high-speed link encryption, well, there is likely no other answer. It's GCM or nothing. Remember that every intelligence agency has a SIGINT branch and an IA (Information Assurance) branch. Sometimes they are different agencies (at least titularly) like GCHQ/CESG, BND/BSI, etc. The NSA does not separate its SIGINT directorate and the IA directorate into different agencies. I think the IA people have shown they do a good job, but they are humans too and make mistakes. Heck, there are things that various IA people do and recommend that I disagree with from weakly to strongly. I weakly disagree with GCM -- I think it's spinach and I say to hell with it, as opposed to thinking it's crap. Would a signals intelligence organization that finds a flaw in what the IA people did tell the IA branch so people can fix it? That's the *real* question. Jon -----BEGIN PGP SIGNATURE----- Version: PGP Universal 3.2.0 (Build 1672) Charset: us-ascii wj8DBQFSKTc3sTedWZOD3gYRAhsoAKCP0xlsuWIE5CMDeBMwqQQ4hVIInwCg7LJX XHkmG7DzCxPubNay86/UL7U= =Eo6n -----END PGP SIGNATURE----- _______________________________________________ The cryptography mailing list cryptography@metzdowd.com http://www.metzdowd.com/mailman/listinfo/cryptography
