Subject: Re: [81attendees] What is it at the bottom of restaurant receipts?
From: Richard Barnes <[email-masked]>
To: "Worley, Dale R (Dale)" <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Date: Tue, 9 Aug 2011 15:53:49 -0400
List-Id: IETF 81 Attendee List <81attendees.ietf.org>

Anyone got one of these machines that we could take apart to try to
get at the key?  Just to verify our findings, of course. <evil grin>

On Tue, Aug 9, 2011 at 3:47 PM, Worley, Dale R (Dale) <[email-masked]> wrote:
> ________________________________________
> From: [email-masked] [[email-masked]] On Behalf Of Richard Barnes [[email-masked]]
>
> But then again, you wouldn't expect that if the hash
> were an HMAC instead of just a digest; it would make a lot of sense
> for the machine to compute the HMAC with a secret key that the tax
> department knows.
> _______________________________________________
>
> I believe I read on some explanatory page that the SRM-generated
> data was "digitally signed", which would suggest an HMAC generated
> with a secret key.
>
> Dale
>