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urcrypt_ed_add_scalarmult_scalarmult_base

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This commit is contained in:
Paul Driver 2020-07-31 14:21:02 -07:00
parent cfb9b21018
commit 5b9f60fd2f
4 changed files with 50 additions and 47 deletions
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62
pkg/urbit/jets/e/ed_add_scalarmult_scalarmult_base.c
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@ -2,61 +2,37 @@
**
*/
#include "all.h"
#include <ed25519.h>
#include <ge.h>
#include <urcrypt.h>
/* functions
*/
u3_noun
u3qc_add_scalarmult_scalarmult_base(u3_atom a,
u3_atom a_point,
u3_atom b)
u3_atom b,
u3_atom c)
{
c3_y met_w;
c3_w ate_w, bet_w, get_w;
met_w = u3r_met(3, a);
if (met_w > 32) {
return u3m_bail(c3__fail);
if ( ((ate_w = u3r_met(3, a)) > 32) ||
((bet_w = u3r_met(3, b)) > 32) ||
((get_w = u3r_met(3, c)) > 32) ) {
return u3_none;
}
c3_y a_y[32];
else {
c3_y a_y[32], b_y[32], c_y[32], out_y[32];
memset(a_y, 0, 32);
u3r_bytes(0, met_w, a_y, a);
met_w = u3r_met(3, a_point);
if (met_w > 32) {
return u3m_bail(c3__fail);
}
c3_y a_point_y[32];
memset(a_point_y, 0, 32);
u3r_bytes(0, met_w, a_point_y, a_point);
met_w = u3r_met(3, b);
if (met_w > 32) {
return u3m_bail(c3__fail);
}
c3_y b_y[32];
memset(b_y, 0, 32);
u3r_bytes(0, met_w, b_y, b);
memset(c_y, 0, 32);
u3r_bytes(0, ate_w, a_y, a);
u3r_bytes(0, bet_w, b_y, b);
u3r_bytes(0, get_w, c_y, c);
ge_p3 A;
if (ge_frombytes_negate_vartime(&A, a_point_y) != 0) {
return u3m_bail(c3__exit);
return
( 0 == urcrypt_ed_add_scalarmult_scalarmult_base(a_y, b_y, c_y, out_y) )
? u3i_bytes(32, out_y)
: u3_none;
}
// Undo the negation from above. See add_scalar.c in the ed25519 distro.
fe_neg(A.X, A.X);
fe_neg(A.T, A.T);
ge_p2 r;
ge_double_scalarmult_vartime(&r, a_y, &A, b_y);
c3_y output_y[32];
ge_tobytes(output_y, &r);
return u3i_bytes(32, output_y);
}
u3_noun

4
pkg/urcrypt/Makefile
View File

@ -4,7 +4,7 @@ PREFIX ?= ./out
################################################################################
.PHONY: all test install clean
.PHONY: all install clean
CFLAGS := $(CFLAGS) -O3 -Wall -Werror -pedantic -std=gnu99
SOURCES = urcrypt.c urcrypt.h
@ -29,4 +29,4 @@ install: all
cp urcrypt.h $(PREFIX)/include/
clean:
rm -rf ./out
rm urcrypt-static.o urcrypt-shared.o liburcrypt.a liburcrypt.so

23
pkg/urcrypt/urcrypt.c
View File

@ -57,6 +57,29 @@ urcrypt_ed_scalarmult_base(uint8_t a[32], uint8_t out[32])
ge_p3_tobytes(out, &R);
}
int
urcrypt_ed_add_scalarmult_scalarmult_base(uint8_t a[32],
uint8_t a_point[32],
uint8_t b[32],
uint8_t out[32])
{
ge_p2 r;
ge_p3 A;
if (ge_frombytes_negate_vartime(&A, a_point) != 0) {
return -1;
}
// Undo the negation from above. See add_scalar.c in the ed25519 distro.
fe_neg(A.X, A.X);
fe_neg(A.T, A.T);
ge_double_scalarmult_vartime(&r, a, &A, b);
ge_tobytes(out, &r);
return 0;
}
void
urcrypt_ed_sign(uint8_t *message,
size_t length,

4
pkg/urcrypt/urcrypt.h
View File

@ -9,6 +9,10 @@
int urcrypt_ed_point_add(uint8_t a[32], uint8_t b[32], uint8_t out[32]);
int urcrypt_ed_scalarmult(uint8_t a[32], uint8_t b[32], uint8_t out[32]);
void urcrypt_ed_scalarmult_base(uint8_t a[32], uint8_t out[32]);
int urcrypt_ed_add_scalarmult_scalarmult_base(uint8_t a[32],
uint8_t a_point[32],
uint8_t b[32],
uint8_t out[32]);
void urcrypt_ed_sign(uint8_t *message,
size_t length,
uint8_t seed[32],