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Decorate group methods with verify macros
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@peterdettman
peterdettman committed Apr 20, 2022
1 parent 485f608 commit 09dbba5
Showing 1 changed file with 116 additions and 7 deletions.
123 changes: 116 additions & 7 deletions src/group_impl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -64,48 +64,83 @@ static const secp256k1_ge secp256k1_ge_const_g = SECP256K1_G;
static const secp256k1_fe secp256k1_fe_const_b = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 7);
#endif

#ifdef VERIFY
static void secp256k1_ge_verify(const secp256k1_ge *a) {
(void)a;
}

static void secp256k1_gej_verify(const secp256k1_gej *a) {
(void)a;
}
#endif

#define VERIFY_GE(ge) VERIFY_SETUP(secp256k1_ge_verify(ge))
#define VERIFY_GEJ(gej) VERIFY_SETUP(secp256k1_gej_verify(gej))

static void secp256k1_ge_set_gej_zinv(secp256k1_ge *r, const secp256k1_gej *a, const secp256k1_fe *zi) {
secp256k1_fe zi2;
secp256k1_fe zi3;
VERIFY_CHECK(!a->infinity);
VERIFY_GEJ(a);

secp256k1_fe_sqr(&zi2, zi);
secp256k1_fe_mul(&zi3, &zi2, zi);
secp256k1_fe_mul(&r->x, &a->x, &zi2);
secp256k1_fe_mul(&r->y, &a->y, &zi3);
r->infinity = a->infinity;

VERIFY_GE(r);
}

static void secp256k1_ge_set_xy(secp256k1_ge *r, const secp256k1_fe *x, const secp256k1_fe *y) {
r->infinity = 0;
r->x = *x;
r->y = *y;

VERIFY_GE(r);
}

static int secp256k1_ge_is_infinity(const secp256k1_ge *a) {
VERIFY_GE(a);
return a->infinity;
}

static void secp256k1_ge_neg(secp256k1_ge *r, const secp256k1_ge *a) {
VERIFY_GE(a);

*r = *a;
secp256k1_fe_normalize_weak(&r->y);
secp256k1_fe_negate(&r->y, &r->y, 1);

VERIFY_GE(r);
}

static void secp256k1_ge_set_gej(secp256k1_ge *r, secp256k1_gej *a) {
secp256k1_fe z2, z3;
r->infinity = a->infinity;

VERIFY_GEJ(a);

secp256k1_fe_inv(&a->z, &a->z);
secp256k1_fe_sqr(&z2, &a->z);
secp256k1_fe_mul(&z3, &a->z, &z2);
secp256k1_fe_mul(&a->x, &a->x, &z2);
secp256k1_fe_mul(&a->y, &a->y, &z3);
secp256k1_fe_set_int(&a->z, 1);

VERIFY_GEJ(a);

r->infinity = a->infinity;
r->x = a->x;
r->y = a->y;

VERIFY_GE(r);
}

static void secp256k1_ge_set_gej_var(secp256k1_ge *r, secp256k1_gej *a) {
secp256k1_fe z2, z3;

VERIFY_GEJ(a);

if (a->infinity) {
secp256k1_ge_set_infinity(r);
return;
Expand All @@ -116,6 +151,9 @@ static void secp256k1_ge_set_gej_var(secp256k1_ge *r, secp256k1_gej *a) {
secp256k1_fe_mul(&a->x, &a->x, &z2);
secp256k1_fe_mul(&a->y, &a->y, &z3);
secp256k1_fe_set_int(&a->z, 1);

VERIFY_GEJ(a);

secp256k1_ge_set_xy(r, &a->x, &a->y);
}

Expand All @@ -125,6 +163,8 @@ static void secp256k1_ge_set_all_gej_var(secp256k1_ge *r, const secp256k1_gej *a
size_t last_i = SIZE_MAX;

for (i = 0; i < len; i++) {
VERIFY_GEJ(&a[i]);

if (a[i].infinity) {
secp256k1_ge_set_infinity(&r[i]);
} else {
Expand Down Expand Up @@ -168,6 +208,8 @@ static void secp256k1_ge_table_set_globalz(size_t len, secp256k1_ge *a, const se
if (len > 0) {
/* Ensure all y values are in weak normal form for fast negation of points */
secp256k1_fe_normalize_weak(&a[i].y);
VERIFY_GE(&a[i]);

zs = zr[i];

/* Work our way backwards, using the z-ratios to scale the x/y values. */
Expand All @@ -190,25 +232,33 @@ static void secp256k1_gej_set_infinity(secp256k1_gej *r) {
secp256k1_fe_clear(&r->x);
secp256k1_fe_clear(&r->y);
secp256k1_fe_clear(&r->z);

VERIFY_GEJ(r);
}

static void secp256k1_ge_set_infinity(secp256k1_ge *r) {
r->infinity = 1;
secp256k1_fe_clear(&r->x);
secp256k1_fe_clear(&r->y);

VERIFY_GE(r);
}

static void secp256k1_gej_clear(secp256k1_gej *r) {
r->infinity = 0;
secp256k1_fe_clear(&r->x);
secp256k1_fe_clear(&r->y);
secp256k1_fe_clear(&r->z);

VERIFY_GEJ(r);
}

static void secp256k1_ge_clear(secp256k1_ge *r) {
r->infinity = 0;
secp256k1_fe_clear(&r->x);
secp256k1_fe_clear(&r->y);

VERIFY_GE(r);
}

static int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int odd) {
Expand All @@ -225,40 +275,56 @@ static int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int o
if (secp256k1_fe_is_odd(&r->y) != odd) {
secp256k1_fe_negate(&r->y, &r->y, 1);
}
return 1;

VERIFY_GE(r);
return 1;
}

static void secp256k1_gej_set_ge(secp256k1_gej *r, const secp256k1_ge *a) {
r->infinity = a->infinity;
r->x = a->x;
r->y = a->y;
secp256k1_fe_set_int(&r->z, 1);
VERIFY_GE(a);

r->infinity = a->infinity;
r->x = a->x;
r->y = a->y;
secp256k1_fe_set_int(&r->z, 1);

VERIFY_GEJ(r);
}

static int secp256k1_gej_eq_x_var(const secp256k1_fe *x, const secp256k1_gej *a) {
secp256k1_fe r, r2;

VERIFY_GEJ(a);
VERIFY_CHECK(!a->infinity);

secp256k1_fe_sqr(&r, &a->z); secp256k1_fe_mul(&r, &r, x);
r2 = a->x; secp256k1_fe_normalize_weak(&r2);
return secp256k1_fe_equal_var(&r, &r2);
}

static void secp256k1_gej_neg(secp256k1_gej *r, const secp256k1_gej *a) {
VERIFY_GEJ(a);

r->infinity = a->infinity;
r->x = a->x;
r->y = a->y;
r->z = a->z;
secp256k1_fe_normalize_weak(&r->y);
secp256k1_fe_negate(&r->y, &r->y, 1);

VERIFY_GEJ(r);
}

static int secp256k1_gej_is_infinity(const secp256k1_gej *a) {
VERIFY_GEJ(a);
return a->infinity;
}

static int secp256k1_ge_is_valid_var(const secp256k1_ge *a) {
secp256k1_fe y2, x3;

VERIFY_GE(a);

if (a->infinity) {
return 0;
}
Expand All @@ -274,6 +340,8 @@ static SECP256K1_INLINE void secp256k1_gej_double(secp256k1_gej *r, const secp25
/* Operations: 3 mul, 4 sqr, 8 add/half/mul_int/negate */
secp256k1_fe l, s, t;

VERIFY_GEJ(a);

r->infinity = a->infinity;

/* Formula used:
Expand All @@ -300,6 +368,8 @@ static SECP256K1_INLINE void secp256k1_gej_double(secp256k1_gej *r, const secp25
secp256k1_fe_mul(&r->y, &t, &l); /* Y3 = L*(X3 + T) (1) */
secp256k1_fe_add(&r->y, &s); /* Y3 = L*(X3 + T) + S^2 (2) */
secp256k1_fe_negate(&r->y, &r->y, 2); /* Y3 = -(L*(X3 + T) + S^2) (3) */

VERIFY_GEJ(r);
}

static void secp256k1_gej_double_var(secp256k1_gej *r, const secp256k1_gej *a, secp256k1_fe *rzr) {
Expand All @@ -313,6 +383,8 @@ static void secp256k1_gej_double_var(secp256k1_gej *r, const secp256k1_gej *a, s
* the infinity flag even though the point doubles to infinity, and the result
* point will be gibberish (z = 0 but infinity = 0).
*/
VERIFY_GEJ(a);

if (a->infinity) {
secp256k1_gej_set_infinity(r);
if (rzr != NULL) {
Expand All @@ -333,6 +405,9 @@ static void secp256k1_gej_add_var(secp256k1_gej *r, const secp256k1_gej *a, cons
/* 12 mul, 4 sqr, 11 add/negate/normalizes_to_zero (ignoring special cases) */
secp256k1_fe z22, z12, u1, u2, s1, s2, h, i, h2, h3, t;

VERIFY_GEJ(a);
VERIFY_GEJ(b);

if (a->infinity) {
VERIFY_CHECK(rzr == NULL);
*r = *b;
Expand Down Expand Up @@ -387,11 +462,17 @@ static void secp256k1_gej_add_var(secp256k1_gej *r, const secp256k1_gej *a, cons
secp256k1_fe_mul(&r->y, &t, &i);
secp256k1_fe_mul(&h3, &h3, &s1);
secp256k1_fe_add(&r->y, &h3);

VERIFY_GEJ(r);
}

static void secp256k1_gej_add_ge_var(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_ge *b, secp256k1_fe *rzr) {
/* 8 mul, 3 sqr, 13 add/negate/normalize_weak/normalizes_to_zero (ignoring special cases) */
secp256k1_fe z12, u1, u2, s1, s2, h, i, h2, h3, t;

VERIFY_GEJ(a);
VERIFY_GE(b);

if (a->infinity) {
VERIFY_CHECK(rzr == NULL);
secp256k1_gej_set_ge(r, b);
Expand Down Expand Up @@ -444,12 +525,17 @@ static void secp256k1_gej_add_ge_var(secp256k1_gej *r, const secp256k1_gej *a, c
secp256k1_fe_mul(&r->y, &t, &i);
secp256k1_fe_mul(&h3, &h3, &s1);
secp256k1_fe_add(&r->y, &h3);

VERIFY_GEJ(r);
}

static void secp256k1_gej_add_zinv_var(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_ge *b, const secp256k1_fe *bzinv) {
/* 9 mul, 3 sqr, 13 add/negate/normalize_weak/normalizes_to_zero (ignoring special cases) */
secp256k1_fe az, z12, u1, u2, s1, s2, h, i, h2, h3, t;

VERIFY_GEJ(a);
VERIFY_GE(b);

if (a->infinity) {
secp256k1_fe bzinv2, bzinv3;
r->infinity = b->infinity;
Expand All @@ -458,6 +544,7 @@ static void secp256k1_gej_add_zinv_var(secp256k1_gej *r, const secp256k1_gej *a,
secp256k1_fe_mul(&r->x, &b->x, &bzinv2);
secp256k1_fe_mul(&r->y, &b->y, &bzinv3);
secp256k1_fe_set_int(&r->z, 1);
VERIFY_GEJ(r);
return;
}
if (b->infinity) {
Expand Down Expand Up @@ -508,14 +595,18 @@ static void secp256k1_gej_add_zinv_var(secp256k1_gej *r, const secp256k1_gej *a,
secp256k1_fe_mul(&r->y, &t, &i);
secp256k1_fe_mul(&h3, &h3, &s1);
secp256k1_fe_add(&r->y, &h3);
}

VERIFY_GEJ(r);
}

static void secp256k1_gej_add_ge(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_ge *b) {
/* Operations: 7 mul, 5 sqr, 24 add/cmov/half/mul_int/negate/normalize_weak/normalizes_to_zero */
secp256k1_fe zz, u1, u2, s1, s2, t, tt, m, n, q, rr;
secp256k1_fe m_alt, rr_alt;
int infinity, degenerate;

VERIFY_GEJ(a);
VERIFY_GE(b);
VERIFY_CHECK(!b->infinity);
VERIFY_CHECK(a->infinity == 0 || a->infinity == 1);

Expand Down Expand Up @@ -626,21 +717,27 @@ static void secp256k1_gej_add_ge(secp256k1_gej *r, const secp256k1_gej *a, const
secp256k1_fe_cmov(&r->y, &b->y, a->infinity);
secp256k1_fe_cmov(&r->z, &secp256k1_fe_one, a->infinity);
r->infinity = infinity;

VERIFY_GEJ(r);
}

static void secp256k1_gej_rescale(secp256k1_gej *r, const secp256k1_fe *s) {
/* Operations: 4 mul, 1 sqr */
secp256k1_fe zz;
VERIFY_GEJ(r);
VERIFY_CHECK(!secp256k1_fe_is_zero(s));
secp256k1_fe_sqr(&zz, s);
secp256k1_fe_mul(&r->x, &r->x, &zz); /* r->x *= s^2 */
secp256k1_fe_mul(&r->y, &r->y, &zz);
secp256k1_fe_mul(&r->y, &r->y, s); /* r->y *= s^3 */
secp256k1_fe_mul(&r->z, &r->z, s); /* r->z *= s */

VERIFY_GEJ(r);
}

static void secp256k1_ge_to_storage(secp256k1_ge_storage *r, const secp256k1_ge *a) {
secp256k1_fe x, y;
VERIFY_GE(a);
VERIFY_CHECK(!a->infinity);
x = a->x;
secp256k1_fe_normalize(&x);
Expand All @@ -654,14 +751,21 @@ static void secp256k1_ge_from_storage(secp256k1_ge *r, const secp256k1_ge_storag
secp256k1_fe_from_storage(&r->x, &a->x);
secp256k1_fe_from_storage(&r->y, &a->y);
r->infinity = 0;

VERIFY_GE(r);
}

static SECP256K1_INLINE void secp256k1_gej_cmov(secp256k1_gej *r, const secp256k1_gej *a, int flag) {
VERIFY_GEJ(r);
VERIFY_GEJ(a);

secp256k1_fe_cmov(&r->x, &a->x, flag);
secp256k1_fe_cmov(&r->y, &a->y, flag);
secp256k1_fe_cmov(&r->z, &a->z, flag);

r->infinity ^= (r->infinity ^ a->infinity) & flag;

VERIFY_GEJ(r);
}

static SECP256K1_INLINE void secp256k1_ge_storage_cmov(secp256k1_ge_storage *r, const secp256k1_ge_storage *a, int flag) {
Expand All @@ -672,13 +776,17 @@ static SECP256K1_INLINE void secp256k1_ge_storage_cmov(secp256k1_ge_storage *r,
static void secp256k1_ge_mul_lambda(secp256k1_ge *r, const secp256k1_ge *a) {
*r = *a;
secp256k1_fe_mul(&r->x, &r->x, &secp256k1_const_beta);

VERIFY_GE(r);
}

static int secp256k1_ge_is_in_correct_subgroup(const secp256k1_ge* ge) {
#ifdef EXHAUSTIVE_TEST_ORDER
secp256k1_gej out;
int i;

VERIFY_GE(ge);

/* A very simple EC multiplication ladder that avoids a dependency on ecmult. */
secp256k1_gej_set_infinity(&out);
for (i = 0; i < 32; ++i) {
Expand All @@ -689,6 +797,7 @@ static int secp256k1_ge_is_in_correct_subgroup(const secp256k1_ge* ge) {
}
return secp256k1_gej_is_infinity(&out);
#else
VERIFY_GE(ge);
(void)ge;
/* The real secp256k1 group has cofactor 1, so the subgroup is the entire curve. */
return 1;
Expand Down

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