Re: [openpgp] OpenPGP encryption block modes

[Bruce Walzer <[e-mail]>]

On Fri, Aug 05, 2022 at 09:41:56AM +0200, Werner Koch wrote:
> On Thu,  4 Aug 2022 10:26, Bruce Walzer said:
> 
> > I thought you guys were mostly doing messaging. Why would performance
> > be important in that environment? Speaking of messaging, wouldn't you
> 
> A major use case is to encrypt bulk data in the range for hundreds of
> GiByte and often up to several TiByte.  And that is not only for
> backups.  It matters whether it takes 6 hours or 45 minutes.

That raises a question for me as I hold the position that OpenPGP does
not need any more block cipher modes. I had the impression that
SEIP-MDC (OCFB-MDC) would be relatively fast as the slow part is
SHA1. SHA1 is one of the faster cryptographic hashes and is hardware
accelerated on common platforms. I assumed that the slowness was
because no one had ever bothered to optimize things. Is this true?

> 
> Actually this is also the reason why we came up with the chunked OCB
> mode - to detect those rare transmission errors more early.

I would really like to comment on this, but I keep getting stuck on
the image of encrypted data running through netcat. Would you be so
kind as to provide a definite use case?

Bruce