mirror/mkp224o
1
0
Fork 0
mirror of https://github.com/cathugger/mkp224o.git synced 2025-12-05 21:27:13 -06:00
Code Issues Packages Projects Releases Wiki Activity

ed25519-donna: batch invert thing hopefully

Browse Source
This commit is contained in:
cathugger
2019-01-27 19:00:28 +02:00
parent f6138d29c4
commit f48239bbd7
1 changed files with 40 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
ed25519/ed25519-donna/curve25519-donna-helpers.h
View File

@@ -48,6 +48,46 @@ curve25519_recip(bignum25519 out, const bignum25519 z) {
/* 2^255 - 21 */ curve25519_mul_noinline(out, b, a); /* 2^255 - 21 */ curve25519_mul_noinline(out, b, a);
} }
const static unsigned char curve25519_packedone[32] = {
1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};
static void
curve25519_setone(bignum25519 out) {
// (cathugger) this hopefuly will get inlined by compiler because im lazy
curve25519_expand(out, curve25519_packedone);
}
/*
* (cathugger)
* idk if recip is same as invert but I hope it is
* if that's the case then we're doing batch invert there
*/
static void
curve25519_batchrecip(bignum25519 *out[], bignum25519 tmp[], bignum25519 * const in[], size_t num) {
bignum25519 ALIGN(16) acc, tmpacc;
size_t i;
curve25519_setone(acc);
for (i = 0; i < num; ++i) {
curve25519_copy(tmp[i], acc);
curve25519_mul(acc, acc, *in[i]);
}
curve25519_recip(acc, acc);
i = num;
while (i--) {
curve25519_mul(tmpacc, acc, *in[i]);
curve25519_mul(*out[i], acc, tmp[i]);
curve25519_copy(acc, tmpacc);
}
}
/* /*
* z^((p-5)/8) = z^(2^252 - 3) * z^((p-5)/8) = z^(2^252 - 3)
*/ */