This fixes a bug where configure would fail or disable static
ecmult tables because it wrongly checks the native compiler using
the target CFLAGS (instead of the native CFLAGS_FOR_BUILD), and
similar for CPPFLAGS and LDFLAGS.
Moreover, this commit adds tests to figure out whether the native
compiler supports the warning flags passed during the build, and it
contains a few minor improvements to the code that checks the native
compiler.
57752d2 [build] Set --enable-jni to no by default instead of auto. (Karl-Johan Alm)
Pull request description:
Having `--enable-jni` be `auto` doesn't make a lot of sense, and results in things like https://github.com/bitcoin/bitcoin/pull/11056.
Tree-SHA512: 27d6ea041f5d6e249857869ab87b8f7b1f6d18ec5ec82d2c46e692cd690b9f5c5857886725901a29d3539d427d8b6154d0c7909cfa2ce30bb3d4460c05708386
We observe that when changing the b-value in the elliptic curve formula
`y^2 = x^3 + ax + b`, the group law is unchanged. Therefore our functions
for secp256k1 will be correct if and only if they are correct when applied
to the curve defined by `y^2 = x^3 + 4` defined over the same field. This
curve has a point P of order 199.
This commit adds a test which computes the subgroup generated by P and
exhaustively checks that addition of every pair of points gives the correct
result.
Unfortunately we cannot test const-time scalar multiplication by the same
mechanism. The reason is that these ecmult functions both compute a wNAF
representation of the scalar, and this representation is tied to the order
of the group.
Testing with the incomplete version of gej_add_ge (found in 5de4c5dff^)
shows that this detects the incompleteness when adding P - 106P, which
is exactly what we expected since 106 is a cube root of 1 mod 199.
Squashed and rebased. Thanks to @theuni and @faizkhan00 for doing
the majority of work here! Also thanks to @btchip for help with debugging
and review.
The use of static makes this somewhat redundant currently, though if
we later have multiple compilation units it will be needed.
This also sets the dllexport needed for shared libraries on win32.
This update is to make libsecp256k1 build on OpenBSD (more specifically OpenBSD 5.7 with Autotools 2.69).
Without the "AM_PROG_CC_C_O" line in configure.ac, ./autogen.sh crashes with "Makefile.am: C objects in subdir but `AM_PROG_CC_C_O' not in `configure.ac'\nautoreconf-2.69: automake failed with exit status: 1".
This vastly shrinks the size of the context required for signing on devices with
memory-mapped Flash.
Tables are generated by the new gen_context tool into a header.
Wno-unused-function is used for the moment because of the checking
functions which are currently only used by VERIFY but are not (yet?)
ifdefed out in normal builds.
This ensures that make will work even if PATH has changed, which is often the
case when cross-compiling.
Fixes cross-compiled builds when integrated into Bitcoin's repo.
Tim Ruffing
Evan Klitzke
Pierre Pronchery
Gregory Maxwell
Pieter Wuille
Karl-Johan Alm
Andrew Poelstra
Cory Fields
Wladimir J. van der Laan
GreenAddress
mlmikael
Thomas Daede
evoskuil
Luke Dashjr
kiwigb
Peter Dettman
Amir Taaki