openbsd/src/lib/libcrypto/ec/ecp_hp_methods.c, branch OPENBSD_7_9_BASEA mirror of https://github.com/libressl/openbsd.git
https://git.lua4.win/openbsd/atom?h=OPENBSD_7_9_BASE2025-08-03T15:44:00+00:00Implement constant time EC scalar multiplication.2025-08-03T15:44:00+00:00jsing2025-08-03T15:44:00+00:00urn:sha1:7037d4c7b0d5603ef79bf7e7f1b33c2cbbce89f2
Replace simplistic non-constant time scalar multiplication with a constant
time version. This is actually faster since we compute multiples of the
point, then double four times and add once. The multiple to add is selected
conditionally, ensuring that the access patterns remain the same regardless
of value.
Inspired by Go's scalar multiplication code.
ok tb@
Remove duplicate computation for b3.2025-08-03T15:08:28+00:00jsing2025-08-03T15:08:28+00:00urn:sha1:862ba5f367a460df8a40dceac15e0369f39cdddfFix resource leaks in ec_points_make_affine()2025-06-01T03:23:33+00:00tb2025-06-01T03:23:33+00:00urn:sha1:5df8087a42612332d095e39b6e5aa10e6a909eed
Add missing BN_CTX_end() and free prod_Z.
CID 552848 (for prod_Z)
Remove bogus alias.2025-05-25T05:43:33+00:00jsing2025-05-25T05:43:33+00:00urn:sha1:093fd1537f471c36878b48ca845f9f073d7bce93Provide an EC method that uses homogeneous projective coordinates.2025-05-25T05:19:26+00:00jsing2025-05-25T05:19:26+00:00urn:sha1:26512301343d2b40a68a67d4f4175ddec368d2fe
This makes use of EC_FIELD_ELEMENT to perform fixed width constant
time operations.
Addition and doubling of points makes use of the formulas from
"Complete addition formulas for prime order elliptic curves"
(https://eprint.iacr.org/2015/1060). These are complete and
operate in constant time.
Further work will continue in tree.
ok tb@