A mirror of https://github.com/libressl/openbsd.git https://git.lua4.win/openbsd/atom?h=OPENBSD_7_9_BASE 2025-12-05T14:12:32+00:00 2025-12-05T14:12:32+00:00 tb 2025-12-05T14:12:32+00:00 urn:sha1:f3f05f0cf8c30a990193e332e26fdd8e54b3f59b This is a first sweep of reducing the number of terribly named macros in bn.h More can go away. Those we need internally go to bn_local.h. Annoyingly bn_internal.h uses some of them, so it includes bn_local.h now. This can be cleaned up later. ok jsing kenjiro 2025-08-02T16:20:00+00:00 jsing 2025-08-02T16:20:00+00:00 urn:sha1:39d33c1bb185014e05def87e04f21103d92dc455 For now this still calls bn_montgomery_multiply_words(), however it can be optimised further in the future. 2025-05-25T05:12:05+00:00 jsing 2025-05-25T05:12:05+00:00 urn:sha1:2f7bf75477a5741ad76c3c793c7ed887b41fcceb Provide EC_FIELD_ELEMENT and EC_FIELD_MODULUS, which allow for operations on fixed width fields in constant time. These can in turn be used to implement Elliptic Curve cryptography for prime fields, without needing to use BN. This will improve the code, reduces timing leaks and enable further optimisation. ok beck@ tb@ 2025-05-25T04:58:32+00:00 jsing 2025-05-25T04:58:32+00:00 urn:sha1:48472c192c88669e44bdba626a93217f709ca4d4 These implement constant time modular addition, subtraction and multiplication in the Montegomery domain. ok tb@ 2025-05-25T04:53:05+00:00 jsing 2025-05-25T04:53:05+00:00 urn:sha1:86cba432b5dc2b5ae7e5ff806bb23d4507eab4e7 2025-05-25T04:30:55+00:00 jsing 2025-05-25T04:30:55+00:00 urn:sha1:cbdbb6515eba8411eeb6f22618e029f1a461aa60 Move bn_add_words() and bn_sub_words() from bn_add.c to bn_add_sub.c. These have effectively been replaced in the previous rewrites. Remove the asserts - if bad lengths are passed the results will be incorrect and things will fail (these should use size_t instead of int, but that is a problem for another day). Provide bn_sub_words_borrow(), which computes a subtraction but only returns the resulting borrow. Provide bn_add_words_masked() and bn_sub_words_masked(), which perform an masked addition or subtraction. These can also be used to implement constant time addition and subtraction, especially for reduction. ok beck@ tb@ 2023-06-25T11:42:26+00:00 jsing 2023-06-25T11:42:26+00:00 urn:sha1:8b6c9ea88db3e77ebd54669fbcaad15b57395510 On BN_ULLONG architectures, the C compiler can usually do a decent job of optimising primitives, however it struggles to see through primitive calls due to type narrowing. As such, providing explicit versions of compound primitives can result in the production of more optimal code. For example, on arm the bn_mulw_addw_addw() primitive can be replaced with a single umaal instruction, which provides significant performance gains. Rather than intermingling #ifdef/#else throughout the header, the BN_ULLONG defines are pulled up above the normal functions. This also allows complex compound primitives to be reused. The conditionals have also been changed from BN_LLONG to BN_ULLONG, since that is what really matters. ok tb@ 2023-06-21T07:48:41+00:00 jsing 2023-06-21T07:48:41+00:00 urn:sha1:b0edbf3f98eba4b1effd31584dae0af06eb2deff On some architectures, we can provide an optimised (often single instruction) count-leading-zero implementation. In order to do this effectively, provide bn_clzw() as a static inline that can be replaced by an architecture specific version. The default implementation defers to the bn_word_clz() function (which may also be architecture specific). ok tb@ 2023-06-21T07:41:55+00:00 jsing 2023-06-21T07:41:55+00:00 urn:sha1:88e97173c6cf4f4ec8c6138cff25d7b1c51a54e9 Provide bn_bitsize(), which performs a constant time scan of a BN in order to determine the bit size of the BN value. Use this for BN_num_bits() such that it is no longer dependent on the bn->top value. ok tb@ 2023-06-12T16:17:24+00:00 jsing 2023-06-12T16:17:24+00:00 urn:sha1:e65682b76bcfaec43a218a52db723a341bec5b90 This includes bn_qwaddqw(), bn_qwsubqw(), bn_qwmulw_addw() and bn_qwmulw_addqw_addw(). These can typically be optimised on architectures that have a reasonable number of general purpose registers. ok tb@