mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-20 05:18:08 +00:00
116 lines
2.9 KiB
C
116 lines
2.9 KiB
C
//
|
|
// Created by Dusan Klinec on 10/05/2018.
|
|
//
|
|
|
|
#include "range_proof.h"
|
|
|
|
|
|
static void xmr_hash_ge25519_to_scalar(bignum256modm r, const ge25519 *p){
|
|
unsigned char buff[32];
|
|
ge25519_pack(buff, p);
|
|
xmr_hash_to_scalar(r, buff, sizeof(buff));
|
|
}
|
|
|
|
void xmr_gen_range_sig(xmr_range_sig_t * sig, ge25519 * C, bignum256modm mask, xmr_amount amount, bignum256modm * last_mask){
|
|
bignum256modm ai[64];
|
|
bignum256modm alpha[64];
|
|
xmr_gen_range_sig_ex(sig, C, mask, amount, last_mask, ai, alpha);
|
|
}
|
|
|
|
void xmr_gen_range_sig_ex(xmr_range_sig_t * sig, ge25519 * C, bignum256modm mask, xmr_amount amount, bignum256modm * last_mask,
|
|
bignum256modm ai[64], bignum256modm alpha[64])
|
|
{
|
|
const unsigned n = XMR_ATOMS;
|
|
bignum256modm a={0};
|
|
bignum256modm si={0};
|
|
bignum256modm c={0};
|
|
bignum256modm ee={0};
|
|
unsigned char buff[32];
|
|
|
|
Hasher kck;
|
|
xmr_hasher_init(&kck);
|
|
|
|
ge25519 C_acc;
|
|
ge25519 C_h;
|
|
ge25519 C_tmp;
|
|
ge25519 L;
|
|
ge25519 Zero;
|
|
|
|
ge25519_set_neutral(&Zero);
|
|
ge25519_set_neutral(&C_acc);
|
|
ge25519_set_xmr_h(&C_h);
|
|
set256_modm(a, 0);
|
|
|
|
#define BB(i) ((amount>>(i)) & 1)
|
|
|
|
// First pass, generates: ai, alpha, Ci, ee, s1
|
|
for(unsigned ii=0; ii<n; ++ii){
|
|
xmr_random_scalar(ai[ii]);
|
|
if (last_mask != NULL && ii == n - 1){
|
|
sub256_modm(ai[ii], *last_mask, a);
|
|
}
|
|
|
|
add256_modm(a, a, ai[ii]); // creating the total mask since you have to pass this to receiver...
|
|
xmr_random_scalar(alpha[ii]);
|
|
|
|
ge25519_scalarmult_base_niels(&L, ge25519_niels_base_multiples, alpha[ii]);
|
|
ge25519_scalarmult_base_niels(&C_tmp, ge25519_niels_base_multiples, ai[ii]);
|
|
|
|
// C_tmp += &Zero if BB(ii) == 0 else &C_h
|
|
ge25519_add(&C_tmp, &C_tmp, BB(ii) == 0 ? &Zero : &C_h, 0);
|
|
ge25519_add(&C_acc, &C_acc, &C_tmp, 0);
|
|
|
|
// Set Ci[ii] to sigs
|
|
ge25519_pack(sig->Ci[ii], &C_tmp);
|
|
|
|
if (BB(ii) == 0) {
|
|
xmr_random_scalar(si);
|
|
xmr_hash_ge25519_to_scalar(c, &L);
|
|
|
|
ge25519_add(&C_tmp, &C_tmp, &C_h, 1); // Ci[ii] -= c_h
|
|
xmr_add_keys2_vartime(&L, si, c, &C_tmp);
|
|
|
|
// Set s1[ii] to sigs
|
|
contract256_modm(sig->asig.s1[ii], si);
|
|
}
|
|
|
|
ge25519_pack(buff, &L);
|
|
xmr_hasher_update(&kck, buff, sizeof(buff));
|
|
|
|
ge25519_double(&C_h, &C_h); // c_H = crypto.scalarmult(c_H, 2)
|
|
}
|
|
|
|
// Compute ee
|
|
xmr_hasher_final(&kck, buff);
|
|
expand256_modm(ee, buff, sizeof(buff));
|
|
|
|
ge25519_set_xmr_h(&C_h);
|
|
|
|
// Second pass, s0, s1
|
|
for(unsigned ii=0; ii<n; ++ii){
|
|
if (BB(ii) == 0){
|
|
mulsub256_modm(si, ai[ii], ee, alpha[ii]);
|
|
contract256_modm(sig->asig.s0[ii], si);
|
|
|
|
} else {
|
|
xmr_random_scalar(si);
|
|
contract256_modm(sig->asig.s0[ii], si);
|
|
|
|
ge25519_unpack_vartime(&C_tmp, sig->Ci[ii]);
|
|
xmr_add_keys2_vartime(&L, si, ee, &C_tmp);
|
|
xmr_hash_ge25519_to_scalar(c, &L);
|
|
|
|
mulsub256_modm(si, ai[ii], c, alpha[ii]);
|
|
contract256_modm(sig->asig.s1[ii], si);
|
|
}
|
|
|
|
ge25519_double(&C_h, &C_h); // c_H = crypto.scalarmult(c_H, 2)
|
|
}
|
|
|
|
ge25519_copy(C, &C_acc);
|
|
copy256_modm(mask, a);
|
|
contract256_modm(sig->asig.ee, ee);
|
|
#undef BB
|
|
}
|
|
|