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mirror of https://github.com/hashcat/hashcat synced 2024-11-28 05:21:38 +01:00

Refactoring: Extract convert_to_window_naf and add some documentation.

This commit is contained in:
Bernard Ladenthin 2020-11-17 21:33:51 +01:00
parent 15bf8b7302
commit 19f4b44840

View File

@ -1730,14 +1730,17 @@ DECLSPEC void point_get_coords (secp256k1_t *r, const u32 *x, const u32 *y)
r->xy[95] = neg[7];
}
DECLSPEC void point_mul (u32 *r, const u32 *k, GLOBAL_AS const secp256k1_t *tmps)
/*
* Convert the tweak/scalar k to w-NAF (window size is 4).
* @param out: naf a pointer to an u32 array with a size of 33.
* @param in: k a pointer to a tweak/scalar which should be converted.
* @return Returns the loop start index.
*/
DECLSPEC int convert_to_window_naf (u32 *naf, const u32 *k)
{
/*
* Convert the tweak/scalar k to w-NAF (window size is 4)
*/
int loop_start = 0;
u32 n[9];
n[0] = 0; // we need this extra slot sometimes for the subtraction to work
n[1] = k[7];
n[2] = k[6];
@ -1748,10 +1751,6 @@ DECLSPEC void point_mul (u32 *r, const u32 *k, GLOBAL_AS const secp256k1_t *tmps
n[7] = k[1];
n[8] = k[0];
u32 naf[32 + 1] = { 0 }; // we need one extra slot
int loop_start = 0;
for (int i = 0; i <= 256; i++)
{
if (n[8] & 1)
@ -1835,8 +1834,14 @@ DECLSPEC void point_mul (u32 *r, const u32 *k, GLOBAL_AS const secp256k1_t *tmps
n[1] = n[1] >> 1 | n[0] << 31;
n[0] = n[0] >> 1;
}
return loop_start;
}
DECLSPEC void point_mul (u32 *r, const u32 *k, GLOBAL_AS const secp256k1_t *tmps)
{
u32 naf[32 + 1] = { 0 }; // we need one extra slot
int loop_start = convert_to_window_naf(naf, k);
// first set:
const u32 multiplier = (naf[loop_start >> 3] >> ((loop_start & 7) << 2)) & 0x0f; // or use u8 ?