Thanks Guys, At the moment I'm trying to distinguish if n > p, as the x co-ordinate does not wrap around n (so x = r in all cases) - to verify if this is always the case
Sent from my iPad > On 20 Dec 2013, at 04:16, Billy Brumley <bbrum...@gmail.com> wrote: > > ... yet it seems you are free to use it as you please (like the rest > of the library does) internally, so it depends on what you are doing. > (Modifying the library or creating an application -- since you posted > code snippets I assumed the former, Matt points out the proper way > externally.) > > BBB > >> On Fri, Dec 20, 2013 at 12:44 AM, Matt Caswell <fr...@baggins.org> wrote: >>> On 19 December 2013 18:52, Billy Brumley <bbrum...@gmail.com> wrote: >>> It's in the EC_GROUP structure: group->field. Check crypto/ec/ec_lcl.h. BBB >> >> Anything in the *lcl.h header files does not form part of the public >> API and you shouldn't really rely on it as it may change. >> >> Better is to use: >> int EC_GROUP_get_curve_GFp(const EC_GROUP *group, BIGNUM *p, BIGNUM >> *a, BIGNUM *b, BN_CTX *ctx); >> >> or >> >> int EC_GROUP_get_curve_GF2m(const EC_GROUP *group, BIGNUM *p, BIGNUM >> *a, BIGNUM *b, BN_CTX *ctx); >> >> as appropriate dependent on the type of curve that you have. >> >> >>> On Thu, Dec 19, 2013 at 9:54 AM, Patrick McCorry <stonecold...@gmail.com> >>> wrote: >>>>>>> From what I can see in the implementation (ecs_ossl.c) when using >>>>>> ecdsa_sign_setup - the 'q' field size is never used! >>>>>> >>>>>> /* >>>>>> * Does the multiplciation of G (generator) * k to produce curve point >>>>>> (x,y) >>>>>> */ >>>>>> EC_POINT_mul(group, temp_point, k, NULL, NULL, ctx) >> >> What you call 'q' (called 'p' within openssl) is used in this >> operation. It is a parameter of the group and is required to do the >> point multiplication. >> >> >> Matt >> ______________________________________________________________________ >> OpenSSL Project http://www.openssl.org >> User Support Mailing List openssl-users@openssl.org >> Automated List Manager majord...@openssl.org > ______________________________________________________________________ > OpenSSL Project http://www.openssl.org > User Support Mailing List openssl-users@openssl.org > Automated List Manager majord...@openssl.org ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
