Re: [COSE] Comments on draft-ietf-cose-rfc8152bis-struct-07 and draft-ietf-cose-rfc8152bis-algs-06

[John Mattsson <[e-mail]>]

“third party verifiability” would be good. In the current text, I do not understand what the four "data origination"/"weak data origination" sentences want to say except “third party verifiability” "and data authentication". 

   "Message Authentication Codes (MACs) provide data authentication and
   integrity protection.  They provide either no or very limited data
   origination.  A MAC, for example, cannot be used to prove the
   identity of the sender to a third party."

    "They provide
     integrity on the data that was encrypted; however, they provide
     either no or very limited data origination.  (One cannot, for
     example, be used to prove the identity of the sender to a third
     party.)  The ability to provide data origination is linked to how the
     CEK is obtained."

   "The use of key wrap loses the
     weak data origination that is provided by the direct encryption
     algorithms."

   "The use of static keys allows for the
     recipient to get a weak version of data origination for the
     message."

/John

-----Original Message-----
From: Jim Schaad <[e-mail]>
Date: Friday, 22 November 2019 at 02:29
To: 'Carsten Bormann' <[e-mail]>, John Mattsson <[e-mail]>
Cc: "[e-mail]" <[e-mail]>
Subject: RE: [COSE] Comments on draft-ietf-cose-rfc8152bis-struct-07 and draft-ietf-cose-rfc8152bis-algs-06

    
    
    -----Original Message-----
    From: COSE <[e-mail]> On Behalf Of Carsten Bormann
    Sent: Friday, November 22, 2019 6:40 AM
    To: John Mattsson <john.mattsson=[e-mail]>
    Cc: [e-mail]
    Subject: Re: [COSE] Comments on draft-ietf-cose-rfc8152bis-struct-07 and draft-ietf-cose-rfc8152bis-algs-06
    
    On Nov 22, 2019, at 06:27, John Mattsson <john.mattsson=[e-mail]> wrote:
    > 
    > Could we replace "data origination" with "non-repudiation"?
    
    Preferably not.
    [JLS]  No really, really not.
    
    If you want the thing that often is identified incorrectly by the latter, please use a more precise term such as “third party verifiability”.  Non-repudation is a legal term.
    [JLS] Non-repudiation is not a legal term.  Repudiation is a legal term.  There is no such thing as non-repudiation, just a legal argument that you can or cannot repudiate something.   I repudiate this signature because Carsten was holding a gun to my head when I made it.  That is a repudiate argument and not the reverse.  Non-repudiation originally had some really weird ideas around having a technological way of proving things like:  It was proven that the key was in my possession. It was proven that only I could have made the signature.  I knew what I was signing a the time.   That is things that cannot be shown.
    
    Jim
    
    
    Provenance is often a term used for the former.
    
    BTW, the text might be easier to read when constructs such as “bistro”, oops, “bstr”, are replaced by “byte string” outside of the CDDL (where byte strings are indeed called “buster”, oops, “bstr”, or also simply “bytes”).  In the previous sentence, for demonstration, I left in the autocorrects as they actually happened :-)
    
    Grüße, Carsten
    
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