Re: [Cfrg] RG Last Call - draft-irtf-cfrg-ocb-00

Ted Krovetz <> Tue, 05 February 2013 22:17 UTC

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From: Ted Krovetz <>
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Date: Tue, 5 Feb 2013 14:17:30 -0800
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Subject: Re: [Cfrg] RG Last Call - draft-irtf-cfrg-ocb-00
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Phil has issued broad licenses for OCB, allowing open-source software implementations and software implementations in non-military contexts and non-commercial non-military hardware implementations. The licenses are at

It is my understanding -- correct me if I'm wrong -- that IP disclosures do not go directly in the RFC but instead get disclosed to the IETF along with the RFC submission. This has been done and the disclosures are at

There is a study of OCB performance vs other AE schemes which includes AES-NI on Westmere hardware.

These have not been updated for Sandy Bridge or Ivy Bridge. I can tell you that under Sandy Bridge OCB takes just 0.87 cycles per byte when processing 4KB messages. The fastest GHASH implementation I know about is Andy Polyakov's OpenSSL implementation that runs at 2.0 cycles per byte (just for GCM's hashing, you'd have to add the cost of encryption to get GCM's overall speed). Sandy Bridge and Ivy Bridge did not improve PCLMULQDQ performance but did improve AESENC performance, meaning that Sandy and Ivy improved OCB's performance much more than GCM's.