On Mar 16, 11:08 am, Chris Garbers <[email protected]> wrote: > cannot talk much about the application as such, but I have a byte- > oriented structure which is limited in size, and need to ensure that > the structure is authentic to the originator. Thus I thought EC > signature was about the only thing appropriate, however even that > seems to be too long, as I only have 20 bytes space left for the > signature. Also see http://www.cryptopp.com/wiki/Elliptic_Curve_Digital_Signature_Algorithm and http://www.cryptopp.com/wiki/Elliptic_Curve_Builder. The ECB page shows how to generate non-standard domain parameters. But the parameters will not meet modern security level recommendations.
> > The counterpart verifying it, must not have possession any secret key, > thus I thought HMAC would be out of question. > Jeff > On 16 Mrz., 13:52, Geoff Beier <[email protected]> wrote: > > > Can you talk about what you're trying to accomplish? It sounds like > > maybe you're trying to use a signature where a truncated HMAC would be > > more appropriate. > > > Geoff > > > On Wed, Mar 16, 2011 at 07:24, Chris Garbers <[email protected]> wrote: > > > My bad. I think signatures cannot be shorter than the key, thus in the > > > example the signature will always be 28 bytes regardless of the hash > > > digest. > > > > Instead, one would have to use a different curve definition with a > > > shorter key. > > > > Chris > > > > [SNIP] -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to [email protected]. More information about Crypto++ and this group is available at http://www.cryptopp.com.
