Re: [Cfrg] Elliptic Curves - signature scheme: friendliness to low memory implementations (ends on June 3rd)

[Ilari Liusvaara <[e-mail]>]

On Mon, Jun 01, 2015 at 10:37:22PM -0700, Andrey Jivsov wrote:
> 
> On 5/29/2015 12:49 PM, Simon Josefsson wrote:
> >Andrey Jivsov <[e-mail]> writes:
> >
> >>Major OpenPGP implementations use streaming mode to sign (e.g. in 'cat
> >>InFile | gpg --clearsign'), just as with encryption, without writing
> >>sensitive data to a temporary file. They depend on IUF. I haven't seen
> >>this with SMIME/CMS -- this is harder, but possible.
> >It is no problem to support streaming of inputs and at the same time
> >support for example EdDSA which does not follow the IUF paradigm.  Don't
> >confuse Unix stdin/stdout streaming with streaming of input to a digital
> >signature algorithm.
> 
> To fix this new demand of low-level crypto there needs to be an engineering
> fix at a higher level. In the case of OpenPGP applications this means the
> buffering of the entire input must happen, somehow.

All signature algorithms in OpenPGP sign message hash, not the message
itself. So streaming input works fine (assuming the hash function is
CR).


-Ilari