Re: [Cfrg] draft-fluhrer-lms-more-parm-sets-01

"Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu> Thu, 23 April 2020 19:42 UTC

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From: "Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu>
To: Russ Housley <housley@vigilsec.com>, Scott Fluhrer <sfluhrer@cisco.com>
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Thread-Topic: [Cfrg] draft-fluhrer-lms-more-parm-sets-01
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Date: Thu, 23 Apr 2020 19:42:07 +0000
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Subject: Re: [Cfrg] draft-fluhrer-lms-more-parm-sets-01
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On 4/23/20, 15:03, "Cfrg on behalf of Russ Housley" <cfrg-bounces@irtf.org on behalf of housley@vigilsec.com> wrote:

    
> 2) SHAKE256-256 and SHAKE256-192:  Why use an Extendable-Output
> Function (XOF)? 

Because it's pseudorandom by provable design rather than conjecture (like in case of SHA-1 and SHA-2)?

> Since the output in the application is always 256 bits or 192 bits, the normal reason
> for picking an XOF does not seem relevant.

There are no reasons NOT to, either.