I've pushed a few more changes to that repository; decompression now works for P-192 and P-224 as well.
I think this is done --- Niels, can you consider this a pull/review request, or would you rather I send a patch (or git-bundle) to the list? The tests have almost but not quite 100% branch coverage. The few uncovered branches are either cases which I think are allowed by other functions' specification but not by their current implementation, or things that I think are mathematically impossible but can't trivially prove. On Wed, May 29, 2019 at 01:25:08AM -0700, Wim Lewis wrote: > I've pushed some work-in-progress to a git repository here: > https://git.lysator.liu.se/wiml/nettle > > There's more to be done, but I would appreciate any comments or feedback > people might have. This is all the time I have available to put into it > right now, but I hope to return to it before too long. > > The changes add two new public functions: > - ecc_point_set_compact() which is like ecc_point_set but accepts a point > in compact form (X and Y's parity/sign rather than X and Y) > - ecc_point_set_from_octets() which interprets a point converted to an > octet string by the rules set out in X9.62 and SEC.1, including compressed, > uncompressed, and hybrid points > > I'm not terribly happy with the name ecc_point_set_compact(); does anyone > have a suggestion for a better name? > > Internals: > > Decompression works for P-256, P-384, and P-521, but it still needs sqrt > implementations for P-192 and P-224. P-224 will be much more complex than > the others (the c^((p-3)/4) shortcut doesn't apply), but there's a paper by > djb on computing square roots in it. > > I added a second slot to the `ecc_modulo` struct to contain a sqrt(u) > implementation (as opposed to the existing sqrt(u/v) implementation). The > slot, and the typedef that describes functions in that slot, need better > names. _______________________________________________ nettle-bugs mailing list nettle-bugs@lists.lysator.liu.se http://lists.lysator.liu.se/mailman/listinfo/nettle-bugs
