frost/secp256k1-zkp
3
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Make WINDOW_G configurable

Browse Source 
This makes WINDOW_G a configurable value in the range of [3..24].
The upper limit of 24 is a defensive choice. The code is probably
correct for values up to 33 but those larger values yield in huge
tables (>= 256MiB), which are i) unlikely to be really beneficial
in practice and ii) increasingly difficult to test.
This commit is contained in:
Tim Ruffing
2019-03-06 13:12:33 +01:00
parent 9c1dda828f
commit a364c95419
2 changed files with 74 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
configure.ac
View File

@@ -186,6 +186,16 @@ AC_ARG_WITH([scalar], [AS_HELP_STRING([--with-scalar=64bit|32bit|auto],
AC_ARG_WITH([asm], [AS_HELP_STRING([--with-asm=x86_64|arm|no|auto]
[Specify assembly optimizations to use. Default is auto (experimental: arm)])],[req_asm=$withval], [req_asm=auto])
# Default is window size 16 (or window size 15 with endomorphism) which needs 1.375 MiB. */
AC_ARG_WITH([ecmult-window], [AS_HELP_STRING([--with-ecmult-window=SIZE|auto],
[window size for ecmult precomputation for verification, specified as integer in range [3..24].]
[Larger values result in possibly better performance at the cost of an exponentially larger precomputed table.]
[The table will store 2^(SIZE-2) * 64 bytes of data but can be larger in memory due]
[to platform-specific padding and alignment. "auto" is a reasonable setting for desktop machines]
[(currently 15 if the endomorphism optimization is disabled and 16 if it is enabled). [default=auto]]
)],
[req_ecmult_window=$withval], [req_ecmult_window=auto])
AC_CHECK_TYPES([__int128])
AC_MSG_CHECKING([for __builtin_expect])
@@ -413,6 +423,32 @@ case $set_scalar in
;;
esac
#set ecmult window size
if test x"$req_ecmult_window" = x"auto"; then
if test x"$use_endomorphism" = x"yes"; then
set_ecmult_window=16
else
set_ecmult_window=15
fi
else
set_ecmult_window=$req_ecmult_window
fi
error_window_size=['window size for ecmult precomputation not an integer in range [3..24] or "auto"']
case $set_ecmult_window in
''|*[[!0-9]]*)
# no valid integer
AC_MSG_ERROR($error_window_size)
;;
*)
if test "$set_ecmult_window" -lt 3 -o "$set_ecmult_window" -gt 24 ; then
# not in range
AC_MSG_ERROR($error_window_size)
fi
AC_DEFINE_UNQUOTED(ECMULT_WINDOW_SIZE, $set_ecmult_window, [Set window size for ecmult precomputation])
;;
esac
if test x"$use_tests" = x"yes"; then
SECP_OPENSSL_CHECK
if test x"$has_openssl_ec" = x"yes"; then
@@ -623,6 +659,7 @@ echo " asm = $set_asm"
echo " bignum = $set_bignum"
echo " field = $set_field"
echo " scalar = $set_scalar"
echo " ecmult window size = $set_ecmult_window"
echo
echo " CC = $CC"
echo " CFLAGS = $CFLAGS"