Subject: Re: [saag] [Technical Errata Reported] RFC5116 (6415)

From: Benjamin Kaduk <[email-masked]>
Date: Sun, 31 Jan 2021 13:46:07 -0800

On Thu, Jan 28, 2021 at 07:30:26PM -0800, RFC Errata System wrote:
> The following errata report has been submitted for RFC5116,
> "An Interface and Algorithms for Authenticated Encryption".
> 
> --------------------------------------
> You may review the report below and at:
> https://www.rfc-editor.org/errata/eid6415
> 
> --------------------------------------
> Type: Technical
> Reported by: Jordan Smith <[email-masked]>
> 
> Section: 3.2
> 
> Original Text
> -------------
>   Implementations
>    SHOULD support 12-octet nonces in which the Counter field is four
>    octets long.
> 
> Corrected Text
> --------------
>   Implementations
>    SHOULD support 12-octet nonces in which the Fixed field is four
>    octets long.

I think it's pretty hard to make an argument that the statement is not what
was intended at the time based solely on the relative lengths of fields in
the figure.  There are different considerations for when one wants a larger
fixed of counter portion, and a change that is in effect retroactively
attempting to change the stated preference seems hard to argue for via the
errata system.

Accordingly, I propose to mark this as rejected since there does not seem
to be clear evidence that the original text is not what was intended.

-Ben

> Notes
> -----
> The ascii diagram given shows the Fixed portion being smaller and the examples given in https://tools.ietf.org/id/draft-mcgrew-iv-gen-01.html also show that the Fixed portion is 4 bytes. 
> 
> Also an 8 byte counter gives 2^64, where a 4 byte counter would only give 2^32
> 
> Instructions:
> -------------
> This erratum is currently posted as "Reported". If necessary, please
> use "Reply All" to discuss whether it should be verified or
> rejected. When a decision is reached, the verifying party  
> can log in to change the status and edit the report, if necessary. 
> 
> --------------------------------------
> RFC5116 (draft-mcgrew-auth-enc-05)
> --------------------------------------
> Title               : An Interface and Algorithms for Authenticated Encryption
> Publication Date    : January 2008
> Author(s)           : D. McGrew
> Category            : PROPOSED STANDARD
> Source              : IETF - NON WORKING GROUP
> Area                : N/A
> Stream              : IETF
> Verifying Party     : IESG
>