ecc: Add an API for X25519 function as gcry_ecc_mul_point.
* configure.ac: Add ecc-ecdh.lo. * cipher/Makefile.am: Add ecc-ecdh.c. * cipher/ecc-common.h (reverse_buffer): Expose. * cipher/ecc-eddsa.c (reverse_buffer): Expose. * cipher/ecc-curves.c (domain_parms): Fix as the errata of RFC. * cipher/ecc-ecdh.c: New. * cipher/ecc-misc.c (_gcry_ecc_mont_decodepoint): Fix for other curves than Curve25519. * src/gcrypt-int.h (_gcry_ecc_mul_point): New. * src/gcrypt.h.in (enum gcry_ecc_curves): New. (gcry_ecc_mul_point): new. * src/libgcrypt.def (gcry_ecc_mul_point): New. * src/libgcrypt.vers (gcry_ecc_mul_point): New. * src/visibility.h (gcry_ecc_mul_point): New. * src/visibility.c (gcry_ecc_mul_point): New. * tests/t-cv25519.c (test_cv_hl): Rename from test_cv. (test_cv_x25519): New. (test_cv): Call both of test_cv_hl and test_cv_x25519.
Add new API gcry_ecc_mul_point for direct use of X25519 function.
"Direct use" means, its inputs and output are binary octet in native
format, while no lengths check inside. It's a responsibility of
caller.
We can use gcry_pk_encrypt for implementing X25519, but the API of
gcry_pk_encrypt uses SEXP format, which is a bit cumbersome.
- GnuPG-bug-id: T4293
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>