diff --git a/src/secp256k1/src/group.h b/src/secp256k1/src/group.h index 32236fb23..c78100cc5 100644 --- a/src/secp256k1/src/group.h +++ b/src/secp256k1/src/group.h @@ -1,142 +1,153 @@ /********************************************************************** * Copyright (c) 2013, 2014 Pieter Wuille * * Distributed under the MIT software license, see the accompanying * * file COPYING or http://www.opensource.org/licenses/mit-license.php.* **********************************************************************/ #ifndef SECP256K1_GROUP_H #define SECP256K1_GROUP_H #include "num.h" #include "field.h" /** A group element of the secp256k1 curve, in affine coordinates. */ typedef struct { secp256k1_fe x; secp256k1_fe y; int infinity; /* whether this represents the point at infinity */ } secp256k1_ge; #define SECP256K1_GE_CONST(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) {SECP256K1_FE_CONST((a),(b),(c),(d),(e),(f),(g),(h)), SECP256K1_FE_CONST((i),(j),(k),(l),(m),(n),(o),(p)), 0} #define SECP256K1_GE_CONST_INFINITY {SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 0), SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 0), 1} /** A group element of the secp256k1 curve, in jacobian coordinates. */ typedef struct { secp256k1_fe x; /* actual X: x/z^2 */ secp256k1_fe y; /* actual Y: y/z^3 */ secp256k1_fe z; int infinity; /* whether this represents the point at infinity */ } secp256k1_gej; #define SECP256K1_GEJ_CONST(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) {SECP256K1_FE_CONST((a),(b),(c),(d),(e),(f),(g),(h)), SECP256K1_FE_CONST((i),(j),(k),(l),(m),(n),(o),(p)), SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1), 0} #define SECP256K1_GEJ_CONST_INFINITY {SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 0), SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 0), SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 0), 1} typedef struct { secp256k1_fe_storage x; secp256k1_fe_storage y; } secp256k1_ge_storage; #define SECP256K1_GE_STORAGE_CONST(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) {SECP256K1_FE_STORAGE_CONST((a),(b),(c),(d),(e),(f),(g),(h)), SECP256K1_FE_STORAGE_CONST((i),(j),(k),(l),(m),(n),(o),(p))} #define SECP256K1_GE_STORAGE_CONST_GET(t) SECP256K1_FE_STORAGE_CONST_GET(t.x), SECP256K1_FE_STORAGE_CONST_GET(t.y) /** Set a group element equal to the point with given X and Y coordinates */ static void secp256k1_ge_set_xy(secp256k1_ge *r, const secp256k1_fe *x, const secp256k1_fe *y); /** Set a group element (affine) equal to the point with the given X coordinate * and a Y coordinate that is a quadratic residue modulo p. The return value * is true iff a coordinate with the given X coordinate exists. */ static int secp256k1_ge_set_xquad(secp256k1_ge *r, const secp256k1_fe *x); /** Set a group element (affine) equal to the point with the given X coordinate, and given oddness * for Y. Return value indicates whether the result is valid. */ static int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int odd); /** Check whether a group element is the point at infinity. */ static int secp256k1_ge_is_infinity(const secp256k1_ge *a); /** Check whether a group element is valid (i.e., on the curve). */ static int secp256k1_ge_is_valid_var(const secp256k1_ge *a); /** Set r equal to the inverse of a (i.e., mirrored around the X axis) */ static void secp256k1_ge_neg(secp256k1_ge *r, const secp256k1_ge *a); /** Set a group element equal to another which is given in jacobian coordinates */ static void secp256k1_ge_set_gej(secp256k1_ge *r, secp256k1_gej *a); /** Set a batch of group elements equal to the inputs given in jacobian coordinates */ static void secp256k1_ge_set_all_gej_var(secp256k1_ge *r, const secp256k1_gej *a, size_t len); /** Bring a batch inputs given in jacobian coordinates (with known z-ratios) to * the same global z "denominator". zr must contain the known z-ratios such * that mul(a[i].z, zr[i+1]) == a[i+1].z. zr[0] is ignored. The x and y * coordinates of the result are stored in r, the common z coordinate is * stored in globalz. */ static void secp256k1_ge_globalz_set_table_gej(size_t len, secp256k1_ge *r, secp256k1_fe *globalz, const secp256k1_gej *a, const secp256k1_fe *zr); /** Set a group element (affine) equal to the point at infinity. */ static void secp256k1_ge_set_infinity(secp256k1_ge *r); /** Set a group element (jacobian) equal to the point at infinity. */ static void secp256k1_gej_set_infinity(secp256k1_gej *r); /** Set a group element (jacobian) equal to another which is given in affine coordinates. */ static void secp256k1_gej_set_ge(secp256k1_gej *r, const secp256k1_ge *a); /** Compare the X coordinate of a group element (jacobian). */ static int secp256k1_gej_eq_x_var(const secp256k1_fe *x, const secp256k1_gej *a); /** Set r equal to the inverse of a (i.e., mirrored around the X axis) */ static void secp256k1_gej_neg(secp256k1_gej *r, const secp256k1_gej *a); /** Check whether a group element is the point at infinity. */ static int secp256k1_gej_is_infinity(const secp256k1_gej *a); /** Check whether a group element's y coordinate is a quadratic residue. */ static int secp256k1_gej_has_quad_y_var(const secp256k1_gej *a); /** Set r equal to the double of a. Constant time. */ static void secp256k1_gej_double(secp256k1_gej *r, const secp256k1_gej *a); /** Set r equal to the double of a. If rzr is not-NULL this sets *rzr such that r->z == a->z * *rzr (where infinity means an implicit z = 0). */ static void secp256k1_gej_double_var(secp256k1_gej *r, const secp256k1_gej *a, secp256k1_fe *rzr); /** Set r equal to the sum of a and b. If rzr is non-NULL this sets *rzr such that r->z == a->z * *rzr (a cannot be infinity in that case). */ static void secp256k1_gej_add_var(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_gej *b, secp256k1_fe *rzr); /** Set r equal to the sum of a and b (with b given in affine coordinates, and not infinity). */ static void secp256k1_gej_add_ge(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_ge *b); /** Set r equal to the sum of a and b (with b given in affine coordinates). This is more efficient than secp256k1_gej_add_var. It is identical to secp256k1_gej_add_ge but without constant-time guarantee, and b is allowed to be infinity. If rzr is non-NULL this sets *rzr such that r->z == a->z * *rzr (a cannot be infinity in that case). */ static void secp256k1_gej_add_ge_var(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_ge *b, secp256k1_fe *rzr); /** Set r equal to the sum of a and b (with the inverse of b's Z coordinate passed as bzinv). */ static void secp256k1_gej_add_zinv_var(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_ge *b, const secp256k1_fe *bzinv); #ifdef USE_ENDOMORPHISM /** Set r to be equal to lambda times a, where lambda is chosen in a way such that this is very fast. */ static void secp256k1_ge_mul_lambda(secp256k1_ge *r, const secp256k1_ge *a); #endif /** Clear a secp256k1_gej to prevent leaking sensitive information. */ static void secp256k1_gej_clear(secp256k1_gej *r); /** Clear a secp256k1_ge to prevent leaking sensitive information. */ static void secp256k1_ge_clear(secp256k1_ge *r); /** Convert a group element to the storage type. */ static void secp256k1_ge_to_storage(secp256k1_ge_storage *r, const secp256k1_ge *a); /** Convert a group element back from the storage type. */ static void secp256k1_ge_from_storage(secp256k1_ge *r, const secp256k1_ge_storage *a); /** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. Both *r and *a must be initialized.*/ static void secp256k1_ge_storage_cmov(secp256k1_ge_storage *r, const secp256k1_ge_storage *a, int flag); /** Rescale a jacobian point by b which must be non-zero. Constant-time. */ static void secp256k1_gej_rescale(secp256k1_gej *r, const secp256k1_fe *b); +/** Determine if a point (which is assumed to be on the curve) is in the correct (sub)group of the curve. + * + * In normal mode, the used group is secp256k1, which has cofactor=1 meaning that every point on the curve is in the + * group, and this function returns always true. + * + * When compiling in exhaustive test mode, a slightly different curve equation is used, leading to a group with a + * (very) small subgroup, and that subgroup is what is used for all cryptographic operations. In that mode, this + * function checks whether a point that is on the curve is in fact also in that subgroup. + */ +static int secp256k1_ge_is_in_correct_subgroup(const secp256k1_ge* ge); + #endif /* SECP256K1_GROUP_H */ diff --git a/src/secp256k1/src/group_impl.h b/src/secp256k1/src/group_impl.h index 357f75bdf..3d62e1021 100644 --- a/src/secp256k1/src/group_impl.h +++ b/src/secp256k1/src/group_impl.h @@ -1,674 +1,695 @@ /********************************************************************** * Copyright (c) 2013, 2014 Pieter Wuille * * Distributed under the MIT software license, see the accompanying * * file COPYING or http://www.opensource.org/licenses/mit-license.php.* **********************************************************************/ #ifndef SECP256K1_GROUP_IMPL_H #define SECP256K1_GROUP_IMPL_H #include "num.h" #include "field.h" #include "group.h" /* These exhaustive group test orders and generators are chosen such that: * - The field size is equal to that of secp256k1, so field code is the same. * - The curve equation is of the form y^2=x^3+B for some constant B. * - The subgroup has a generator 2*P, where P.x=1. * - The subgroup has size less than 1000 to permit exhaustive testing. * - The subgroup admits an endomorphism of the form lambda*(x,y) == (beta*x,y). * * These parameters are generated using sage/gen_exhaustive_groups.sage. */ #if defined(EXHAUSTIVE_TEST_ORDER) # if EXHAUSTIVE_TEST_ORDER == 13 static const secp256k1_ge secp256k1_ge_const_g = SECP256K1_GE_CONST( 0xc3459c3d, 0x35326167, 0xcd86cce8, 0x07a2417f, 0x5b8bd567, 0xde8538ee, 0x0d507b0c, 0xd128f5bb, 0x8e467fec, 0xcd30000a, 0x6cc1184e, 0x25d382c2, 0xa2f4494e, 0x2fbe9abc, 0x8b64abac, 0xd005fb24 ); static const secp256k1_fe secp256k1_fe_const_b = SECP256K1_FE_CONST( 0x3d3486b2, 0x159a9ca5, 0xc75638be, 0xb23a69bc, 0x946a45ab, 0x24801247, 0xb4ed2b8e, 0x26b6a417 ); # elif EXHAUSTIVE_TEST_ORDER == 199 static const secp256k1_ge secp256k1_ge_const_g = SECP256K1_GE_CONST( 0x226e653f, 0xc8df7744, 0x9bacbf12, 0x7d1dcbf9, 0x87f05b2a, 0xe7edbd28, 0x1f564575, 0xc48dcf18, 0xa13872c2, 0xe933bb17, 0x5d9ffd5b, 0xb5b6e10c, 0x57fe3c00, 0xbaaaa15a, 0xe003ec3e, 0x9c269bae ); static const secp256k1_fe secp256k1_fe_const_b = SECP256K1_FE_CONST( 0x2cca28fa, 0xfc614b80, 0x2a3db42b, 0x00ba00b1, 0xbea8d943, 0xdace9ab2, 0x9536daea, 0x0074defb ); # else # error No known generator for the specified exhaustive test group order. # endif #else /** Generator for secp256k1, value 'g' defined in * "Standards for Efficient Cryptography" (SEC2) 2.7.1. */ static const secp256k1_ge secp256k1_ge_const_g = SECP256K1_GE_CONST( 0x79BE667EUL, 0xF9DCBBACUL, 0x55A06295UL, 0xCE870B07UL, 0x029BFCDBUL, 0x2DCE28D9UL, 0x59F2815BUL, 0x16F81798UL, 0x483ADA77UL, 0x26A3C465UL, 0x5DA4FBFCUL, 0x0E1108A8UL, 0xFD17B448UL, 0xA6855419UL, 0x9C47D08FUL, 0xFB10D4B8UL ); static const secp256k1_fe secp256k1_fe_const_b = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 7); #endif static void secp256k1_ge_set_gej_zinv(secp256k1_ge *r, const secp256k1_gej *a, const secp256k1_fe *zi) { secp256k1_fe zi2; secp256k1_fe zi3; 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; } 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; } static int secp256k1_ge_is_infinity(const secp256k1_ge *a) { return a->infinity; } static void secp256k1_ge_neg(secp256k1_ge *r, const secp256k1_ge *a) { *r = *a; secp256k1_fe_normalize_weak(&r->y); secp256k1_fe_negate(&r->y, &r->y, 1); } static void secp256k1_ge_set_gej(secp256k1_ge *r, secp256k1_gej *a) { secp256k1_fe z2, z3; r->infinity = a->infinity; 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); r->x = a->x; r->y = a->y; } static void secp256k1_ge_set_gej_var(secp256k1_ge *r, secp256k1_gej *a) { secp256k1_fe z2, z3; r->infinity = a->infinity; if (a->infinity) { return; } secp256k1_fe_inv_var(&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); r->x = a->x; r->y = a->y; } static void secp256k1_ge_set_all_gej_var(secp256k1_ge *r, const secp256k1_gej *a, size_t len) { secp256k1_fe u; size_t i; size_t last_i = SIZE_MAX; for (i = 0; i < len; i++) { if (!a[i].infinity) { /* Use destination's x coordinates as scratch space */ if (last_i == SIZE_MAX) { r[i].x = a[i].z; } else { secp256k1_fe_mul(&r[i].x, &r[last_i].x, &a[i].z); } last_i = i; } } if (last_i == SIZE_MAX) { return; } secp256k1_fe_inv_var(&u, &r[last_i].x); i = last_i; while (i > 0) { i--; if (!a[i].infinity) { secp256k1_fe_mul(&r[last_i].x, &r[i].x, &u); secp256k1_fe_mul(&u, &u, &a[last_i].z); last_i = i; } } VERIFY_CHECK(!a[last_i].infinity); r[last_i].x = u; for (i = 0; i < len; i++) { r[i].infinity = a[i].infinity; if (!a[i].infinity) { secp256k1_ge_set_gej_zinv(&r[i], &a[i], &r[i].x); } } } static void secp256k1_ge_globalz_set_table_gej(size_t len, secp256k1_ge *r, secp256k1_fe *globalz, const secp256k1_gej *a, const secp256k1_fe *zr) { size_t i = len - 1; secp256k1_fe zs; if (len > 0) { /* The z of the final point gives us the "global Z" for the table. */ r[i].x = a[i].x; r[i].y = a[i].y; /* Ensure all y values are in weak normal form for fast negation of points */ secp256k1_fe_normalize_weak(&r[i].y); *globalz = a[i].z; r[i].infinity = 0; zs = zr[i]; /* Work our way backwards, using the z-ratios to scale the x/y values. */ while (i > 0) { if (i != len - 1) { secp256k1_fe_mul(&zs, &zs, &zr[i]); } i--; secp256k1_ge_set_gej_zinv(&r[i], &a[i], &zs); } } } static void secp256k1_gej_set_infinity(secp256k1_gej *r) { r->infinity = 1; secp256k1_fe_clear(&r->x); secp256k1_fe_clear(&r->y); secp256k1_fe_clear(&r->z); } static void secp256k1_ge_set_infinity(secp256k1_ge *r) { r->infinity = 1; secp256k1_fe_clear(&r->x); secp256k1_fe_clear(&r->y); } 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); } static void secp256k1_ge_clear(secp256k1_ge *r) { r->infinity = 0; secp256k1_fe_clear(&r->x); secp256k1_fe_clear(&r->y); } static int secp256k1_ge_set_xquad(secp256k1_ge *r, const secp256k1_fe *x) { secp256k1_fe x2, x3; r->x = *x; secp256k1_fe_sqr(&x2, x); secp256k1_fe_mul(&x3, x, &x2); r->infinity = 0; secp256k1_fe_add(&x3, &secp256k1_fe_const_b); return secp256k1_fe_sqrt(&r->y, &x3); } static int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int odd) { if (!secp256k1_ge_set_xquad(r, x)) { return 0; } secp256k1_fe_normalize_var(&r->y); if (secp256k1_fe_is_odd(&r->y) != odd) { secp256k1_fe_negate(&r->y, &r->y, 1); } 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); } static int secp256k1_gej_eq_x_var(const secp256k1_fe *x, const secp256k1_gej *a) { secp256k1_fe r, r2; 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) { 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); } static int secp256k1_gej_is_infinity(const secp256k1_gej *a) { return a->infinity; } static int secp256k1_ge_is_valid_var(const secp256k1_ge *a) { secp256k1_fe y2, x3; if (a->infinity) { return 0; } /* y^2 = x^3 + 7 */ secp256k1_fe_sqr(&y2, &a->y); secp256k1_fe_sqr(&x3, &a->x); secp256k1_fe_mul(&x3, &x3, &a->x); secp256k1_fe_add(&x3, &secp256k1_fe_const_b); secp256k1_fe_normalize_weak(&x3); return secp256k1_fe_equal_var(&y2, &x3); } static SECP256K1_INLINE void secp256k1_gej_double(secp256k1_gej *r, const secp256k1_gej *a) { /* Operations: 3 mul, 4 sqr, 0 normalize, 12 mul_int/add/negate. * * Note that there is an implementation described at * https://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#doubling-dbl-2009-l * which trades a multiply for a square, but in practice this is actually slower, * mainly because it requires more normalizations. */ secp256k1_fe t1,t2,t3,t4; r->infinity = a->infinity; secp256k1_fe_mul(&r->z, &a->z, &a->y); secp256k1_fe_mul_int(&r->z, 2); /* Z' = 2*Y*Z (2) */ secp256k1_fe_sqr(&t1, &a->x); secp256k1_fe_mul_int(&t1, 3); /* T1 = 3*X^2 (3) */ secp256k1_fe_sqr(&t2, &t1); /* T2 = 9*X^4 (1) */ secp256k1_fe_sqr(&t3, &a->y); secp256k1_fe_mul_int(&t3, 2); /* T3 = 2*Y^2 (2) */ secp256k1_fe_sqr(&t4, &t3); secp256k1_fe_mul_int(&t4, 2); /* T4 = 8*Y^4 (2) */ secp256k1_fe_mul(&t3, &t3, &a->x); /* T3 = 2*X*Y^2 (1) */ r->x = t3; secp256k1_fe_mul_int(&r->x, 4); /* X' = 8*X*Y^2 (4) */ secp256k1_fe_negate(&r->x, &r->x, 4); /* X' = -8*X*Y^2 (5) */ secp256k1_fe_add(&r->x, &t2); /* X' = 9*X^4 - 8*X*Y^2 (6) */ secp256k1_fe_negate(&t2, &t2, 1); /* T2 = -9*X^4 (2) */ secp256k1_fe_mul_int(&t3, 6); /* T3 = 12*X*Y^2 (6) */ secp256k1_fe_add(&t3, &t2); /* T3 = 12*X*Y^2 - 9*X^4 (8) */ secp256k1_fe_mul(&r->y, &t1, &t3); /* Y' = 36*X^3*Y^2 - 27*X^6 (1) */ secp256k1_fe_negate(&t2, &t4, 2); /* T2 = -8*Y^4 (3) */ secp256k1_fe_add(&r->y, &t2); /* Y' = 36*X^3*Y^2 - 27*X^6 - 8*Y^4 (4) */ } static void secp256k1_gej_double_var(secp256k1_gej *r, const secp256k1_gej *a, secp256k1_fe *rzr) { /** For secp256k1, 2Q is infinity if and only if Q is infinity. This is because if 2Q = infinity, * Q must equal -Q, or that Q.y == -(Q.y), or Q.y is 0. For a point on y^2 = x^3 + 7 to have * y=0, x^3 must be -7 mod p. However, -7 has no cube root mod p. * * Having said this, if this function receives a point on a sextic twist, e.g. by * a fault attack, it is possible for y to be 0. This happens for y^2 = x^3 + 6, * since -6 does have a cube root mod p. For this point, this function will not set * the infinity flag even though the point doubles to infinity, and the result * point will be gibberish (z = 0 but infinity = 0). */ if (a->infinity) { r->infinity = 1; if (rzr != NULL) { secp256k1_fe_set_int(rzr, 1); } return; } if (rzr != NULL) { *rzr = a->y; secp256k1_fe_normalize_weak(rzr); secp256k1_fe_mul_int(rzr, 2); } secp256k1_gej_double(r, a); } static void secp256k1_gej_add_var(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_gej *b, secp256k1_fe *rzr) { /* Operations: 12 mul, 4 sqr, 2 normalize, 12 mul_int/add/negate */ secp256k1_fe z22, z12, u1, u2, s1, s2, h, i, i2, h2, h3, t; if (a->infinity) { VERIFY_CHECK(rzr == NULL); *r = *b; return; } if (b->infinity) { if (rzr != NULL) { secp256k1_fe_set_int(rzr, 1); } *r = *a; return; } r->infinity = 0; secp256k1_fe_sqr(&z22, &b->z); secp256k1_fe_sqr(&z12, &a->z); secp256k1_fe_mul(&u1, &a->x, &z22); secp256k1_fe_mul(&u2, &b->x, &z12); secp256k1_fe_mul(&s1, &a->y, &z22); secp256k1_fe_mul(&s1, &s1, &b->z); secp256k1_fe_mul(&s2, &b->y, &z12); secp256k1_fe_mul(&s2, &s2, &a->z); secp256k1_fe_negate(&h, &u1, 1); secp256k1_fe_add(&h, &u2); secp256k1_fe_negate(&i, &s1, 1); secp256k1_fe_add(&i, &s2); if (secp256k1_fe_normalizes_to_zero_var(&h)) { if (secp256k1_fe_normalizes_to_zero_var(&i)) { secp256k1_gej_double_var(r, a, rzr); } else { if (rzr != NULL) { secp256k1_fe_set_int(rzr, 0); } secp256k1_gej_set_infinity(r); } return; } secp256k1_fe_sqr(&i2, &i); secp256k1_fe_sqr(&h2, &h); secp256k1_fe_mul(&h3, &h, &h2); secp256k1_fe_mul(&h, &h, &b->z); if (rzr != NULL) { *rzr = h; } secp256k1_fe_mul(&r->z, &a->z, &h); secp256k1_fe_mul(&t, &u1, &h2); r->x = t; secp256k1_fe_mul_int(&r->x, 2); secp256k1_fe_add(&r->x, &h3); secp256k1_fe_negate(&r->x, &r->x, 3); secp256k1_fe_add(&r->x, &i2); secp256k1_fe_negate(&r->y, &r->x, 5); secp256k1_fe_add(&r->y, &t); secp256k1_fe_mul(&r->y, &r->y, &i); secp256k1_fe_mul(&h3, &h3, &s1); secp256k1_fe_negate(&h3, &h3, 1); secp256k1_fe_add(&r->y, &h3); } 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, 4 normalize, 12 mul_int/add/negate */ secp256k1_fe z12, u1, u2, s1, s2, h, i, i2, h2, h3, t; if (a->infinity) { VERIFY_CHECK(rzr == NULL); secp256k1_gej_set_ge(r, b); return; } if (b->infinity) { if (rzr != NULL) { secp256k1_fe_set_int(rzr, 1); } *r = *a; return; } r->infinity = 0; secp256k1_fe_sqr(&z12, &a->z); u1 = a->x; secp256k1_fe_normalize_weak(&u1); secp256k1_fe_mul(&u2, &b->x, &z12); s1 = a->y; secp256k1_fe_normalize_weak(&s1); secp256k1_fe_mul(&s2, &b->y, &z12); secp256k1_fe_mul(&s2, &s2, &a->z); secp256k1_fe_negate(&h, &u1, 1); secp256k1_fe_add(&h, &u2); secp256k1_fe_negate(&i, &s1, 1); secp256k1_fe_add(&i, &s2); if (secp256k1_fe_normalizes_to_zero_var(&h)) { if (secp256k1_fe_normalizes_to_zero_var(&i)) { secp256k1_gej_double_var(r, a, rzr); } else { if (rzr != NULL) { secp256k1_fe_set_int(rzr, 0); } secp256k1_gej_set_infinity(r); } return; } secp256k1_fe_sqr(&i2, &i); secp256k1_fe_sqr(&h2, &h); secp256k1_fe_mul(&h3, &h, &h2); if (rzr != NULL) { *rzr = h; } secp256k1_fe_mul(&r->z, &a->z, &h); secp256k1_fe_mul(&t, &u1, &h2); r->x = t; secp256k1_fe_mul_int(&r->x, 2); secp256k1_fe_add(&r->x, &h3); secp256k1_fe_negate(&r->x, &r->x, 3); secp256k1_fe_add(&r->x, &i2); secp256k1_fe_negate(&r->y, &r->x, 5); secp256k1_fe_add(&r->y, &t); secp256k1_fe_mul(&r->y, &r->y, &i); secp256k1_fe_mul(&h3, &h3, &s1); secp256k1_fe_negate(&h3, &h3, 1); secp256k1_fe_add(&r->y, &h3); } 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, 4 normalize, 12 mul_int/add/negate */ secp256k1_fe az, z12, u1, u2, s1, s2, h, i, i2, h2, h3, t; if (b->infinity) { *r = *a; return; } if (a->infinity) { secp256k1_fe bzinv2, bzinv3; r->infinity = b->infinity; secp256k1_fe_sqr(&bzinv2, bzinv); secp256k1_fe_mul(&bzinv3, &bzinv2, bzinv); secp256k1_fe_mul(&r->x, &b->x, &bzinv2); secp256k1_fe_mul(&r->y, &b->y, &bzinv3); secp256k1_fe_set_int(&r->z, 1); return; } r->infinity = 0; /** We need to calculate (rx,ry,rz) = (ax,ay,az) + (bx,by,1/bzinv). Due to * secp256k1's isomorphism we can multiply the Z coordinates on both sides * by bzinv, and get: (rx,ry,rz*bzinv) = (ax,ay,az*bzinv) + (bx,by,1). * This means that (rx,ry,rz) can be calculated as * (ax,ay,az*bzinv) + (bx,by,1), when not applying the bzinv factor to rz. * The variable az below holds the modified Z coordinate for a, which is used * for the computation of rx and ry, but not for rz. */ secp256k1_fe_mul(&az, &a->z, bzinv); secp256k1_fe_sqr(&z12, &az); u1 = a->x; secp256k1_fe_normalize_weak(&u1); secp256k1_fe_mul(&u2, &b->x, &z12); s1 = a->y; secp256k1_fe_normalize_weak(&s1); secp256k1_fe_mul(&s2, &b->y, &z12); secp256k1_fe_mul(&s2, &s2, &az); secp256k1_fe_negate(&h, &u1, 1); secp256k1_fe_add(&h, &u2); secp256k1_fe_negate(&i, &s1, 1); secp256k1_fe_add(&i, &s2); if (secp256k1_fe_normalizes_to_zero_var(&h)) { if (secp256k1_fe_normalizes_to_zero_var(&i)) { secp256k1_gej_double_var(r, a, NULL); } else { secp256k1_gej_set_infinity(r); } return; } secp256k1_fe_sqr(&i2, &i); secp256k1_fe_sqr(&h2, &h); secp256k1_fe_mul(&h3, &h, &h2); r->z = a->z; secp256k1_fe_mul(&r->z, &r->z, &h); secp256k1_fe_mul(&t, &u1, &h2); r->x = t; secp256k1_fe_mul_int(&r->x, 2); secp256k1_fe_add(&r->x, &h3); secp256k1_fe_negate(&r->x, &r->x, 3); secp256k1_fe_add(&r->x, &i2); secp256k1_fe_negate(&r->y, &r->x, 5); secp256k1_fe_add(&r->y, &t); secp256k1_fe_mul(&r->y, &r->y, &i); secp256k1_fe_mul(&h3, &h3, &s1); secp256k1_fe_negate(&h3, &h3, 1); secp256k1_fe_add(&r->y, &h3); } static void secp256k1_gej_add_ge(secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_ge *b) { /* Operations: 7 mul, 5 sqr, 4 normalize, 21 mul_int/add/negate/cmov */ static const secp256k1_fe fe_1 = SECP256K1_FE_CONST(0, 0, 0, 0, 0, 0, 0, 1); secp256k1_fe zz, u1, u2, s1, s2, t, tt, m, n, q, rr; secp256k1_fe m_alt, rr_alt; int infinity, degenerate; VERIFY_CHECK(!b->infinity); VERIFY_CHECK(a->infinity == 0 || a->infinity == 1); /** In: * Eric Brier and Marc Joye, Weierstrass Elliptic Curves and Side-Channel Attacks. * In D. Naccache and P. Paillier, Eds., Public Key Cryptography, vol. 2274 of Lecture Notes in Computer Science, pages 335-345. Springer-Verlag, 2002. * we find as solution for a unified addition/doubling formula: * lambda = ((x1 + x2)^2 - x1 * x2 + a) / (y1 + y2), with a = 0 for secp256k1's curve equation. * x3 = lambda^2 - (x1 + x2) * 2*y3 = lambda * (x1 + x2 - 2 * x3) - (y1 + y2). * * Substituting x_i = Xi / Zi^2 and yi = Yi / Zi^3, for i=1,2,3, gives: * U1 = X1*Z2^2, U2 = X2*Z1^2 * S1 = Y1*Z2^3, S2 = Y2*Z1^3 * Z = Z1*Z2 * T = U1+U2 * M = S1+S2 * Q = T*M^2 * R = T^2-U1*U2 * X3 = 4*(R^2-Q) * Y3 = 4*(R*(3*Q-2*R^2)-M^4) * Z3 = 2*M*Z * (Note that the paper uses xi = Xi / Zi and yi = Yi / Zi instead.) * * This formula has the benefit of being the same for both addition * of distinct points and doubling. However, it breaks down in the * case that either point is infinity, or that y1 = -y2. We handle * these cases in the following ways: * * - If b is infinity we simply bail by means of a VERIFY_CHECK. * * - If a is infinity, we detect this, and at the end of the * computation replace the result (which will be meaningless, * but we compute to be constant-time) with b.x : b.y : 1. * * - If a = -b, we have y1 = -y2, which is a degenerate case. * But here the answer is infinity, so we simply set the * infinity flag of the result, overriding the computed values * without even needing to cmov. * * - If y1 = -y2 but x1 != x2, which does occur thanks to certain * properties of our curve (specifically, 1 has nontrivial cube * roots in our field, and the curve equation has no x coefficient) * then the answer is not infinity but also not given by the above * equation. In this case, we cmov in place an alternate expression * for lambda. Specifically (y1 - y2)/(x1 - x2). Where both these * expressions for lambda are defined, they are equal, and can be * obtained from each other by multiplication by (y1 + y2)/(y1 + y2) * then substitution of x^3 + 7 for y^2 (using the curve equation). * For all pairs of nonzero points (a, b) at least one is defined, * so this covers everything. */ secp256k1_fe_sqr(&zz, &a->z); /* z = Z1^2 */ u1 = a->x; secp256k1_fe_normalize_weak(&u1); /* u1 = U1 = X1*Z2^2 (1) */ secp256k1_fe_mul(&u2, &b->x, &zz); /* u2 = U2 = X2*Z1^2 (1) */ s1 = a->y; secp256k1_fe_normalize_weak(&s1); /* s1 = S1 = Y1*Z2^3 (1) */ secp256k1_fe_mul(&s2, &b->y, &zz); /* s2 = Y2*Z1^2 (1) */ secp256k1_fe_mul(&s2, &s2, &a->z); /* s2 = S2 = Y2*Z1^3 (1) */ t = u1; secp256k1_fe_add(&t, &u2); /* t = T = U1+U2 (2) */ m = s1; secp256k1_fe_add(&m, &s2); /* m = M = S1+S2 (2) */ secp256k1_fe_sqr(&rr, &t); /* rr = T^2 (1) */ secp256k1_fe_negate(&m_alt, &u2, 1); /* Malt = -X2*Z1^2 */ secp256k1_fe_mul(&tt, &u1, &m_alt); /* tt = -U1*U2 (2) */ secp256k1_fe_add(&rr, &tt); /* rr = R = T^2-U1*U2 (3) */ /** If lambda = R/M = 0/0 we have a problem (except in the "trivial" * case that Z = z1z2 = 0, and this is special-cased later on). */ degenerate = secp256k1_fe_normalizes_to_zero(&m) & secp256k1_fe_normalizes_to_zero(&rr); /* This only occurs when y1 == -y2 and x1^3 == x2^3, but x1 != x2. * This means either x1 == beta*x2 or beta*x1 == x2, where beta is * a nontrivial cube root of one. In either case, an alternate * non-indeterminate expression for lambda is (y1 - y2)/(x1 - x2), * so we set R/M equal to this. */ rr_alt = s1; secp256k1_fe_mul_int(&rr_alt, 2); /* rr = Y1*Z2^3 - Y2*Z1^3 (2) */ secp256k1_fe_add(&m_alt, &u1); /* Malt = X1*Z2^2 - X2*Z1^2 */ secp256k1_fe_cmov(&rr_alt, &rr, !degenerate); secp256k1_fe_cmov(&m_alt, &m, !degenerate); /* Now Ralt / Malt = lambda and is guaranteed not to be 0/0. * From here on out Ralt and Malt represent the numerator * and denominator of lambda; R and M represent the explicit * expressions x1^2 + x2^2 + x1x2 and y1 + y2. */ secp256k1_fe_sqr(&n, &m_alt); /* n = Malt^2 (1) */ secp256k1_fe_mul(&q, &n, &t); /* q = Q = T*Malt^2 (1) */ /* These two lines use the observation that either M == Malt or M == 0, * so M^3 * Malt is either Malt^4 (which is computed by squaring), or * zero (which is "computed" by cmov). So the cost is one squaring * versus two multiplications. */ secp256k1_fe_sqr(&n, &n); secp256k1_fe_cmov(&n, &m, degenerate); /* n = M^3 * Malt (2) */ secp256k1_fe_sqr(&t, &rr_alt); /* t = Ralt^2 (1) */ secp256k1_fe_mul(&r->z, &a->z, &m_alt); /* r->z = Malt*Z (1) */ infinity = secp256k1_fe_normalizes_to_zero(&r->z) * (1 - a->infinity); secp256k1_fe_mul_int(&r->z, 2); /* r->z = Z3 = 2*Malt*Z (2) */ secp256k1_fe_negate(&q, &q, 1); /* q = -Q (2) */ secp256k1_fe_add(&t, &q); /* t = Ralt^2-Q (3) */ secp256k1_fe_normalize_weak(&t); r->x = t; /* r->x = Ralt^2-Q (1) */ secp256k1_fe_mul_int(&t, 2); /* t = 2*x3 (2) */ secp256k1_fe_add(&t, &q); /* t = 2*x3 - Q: (4) */ secp256k1_fe_mul(&t, &t, &rr_alt); /* t = Ralt*(2*x3 - Q) (1) */ secp256k1_fe_add(&t, &n); /* t = Ralt*(2*x3 - Q) + M^3*Malt (3) */ secp256k1_fe_negate(&r->y, &t, 3); /* r->y = Ralt*(Q - 2x3) - M^3*Malt (4) */ secp256k1_fe_normalize_weak(&r->y); secp256k1_fe_mul_int(&r->x, 4); /* r->x = X3 = 4*(Ralt^2-Q) */ secp256k1_fe_mul_int(&r->y, 4); /* r->y = Y3 = 4*Ralt*(Q - 2x3) - 4*M^3*Malt (4) */ /** In case a->infinity == 1, replace r with (b->x, b->y, 1). */ secp256k1_fe_cmov(&r->x, &b->x, a->infinity); secp256k1_fe_cmov(&r->y, &b->y, a->infinity); secp256k1_fe_cmov(&r->z, &fe_1, a->infinity); r->infinity = infinity; } static void secp256k1_gej_rescale(secp256k1_gej *r, const secp256k1_fe *s) { /* Operations: 4 mul, 1 sqr */ secp256k1_fe zz; 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 */ } static void secp256k1_ge_to_storage(secp256k1_ge_storage *r, const secp256k1_ge *a) { secp256k1_fe x, y; VERIFY_CHECK(!a->infinity); x = a->x; secp256k1_fe_normalize(&x); y = a->y; secp256k1_fe_normalize(&y); secp256k1_fe_to_storage(&r->x, &x); secp256k1_fe_to_storage(&r->y, &y); } static void secp256k1_ge_from_storage(secp256k1_ge *r, const secp256k1_ge_storage *a) { secp256k1_fe_from_storage(&r->x, &a->x); secp256k1_fe_from_storage(&r->y, &a->y); r->infinity = 0; } static SECP256K1_INLINE void secp256k1_ge_storage_cmov(secp256k1_ge_storage *r, const secp256k1_ge_storage *a, int flag) { secp256k1_fe_storage_cmov(&r->x, &a->x, flag); secp256k1_fe_storage_cmov(&r->y, &a->y, flag); } #ifdef USE_ENDOMORPHISM static void secp256k1_ge_mul_lambda(secp256k1_ge *r, const secp256k1_ge *a) { static const secp256k1_fe beta = SECP256K1_FE_CONST( 0x7ae96a2bul, 0x657c0710ul, 0x6e64479eul, 0xac3434e9ul, 0x9cf04975ul, 0x12f58995ul, 0xc1396c28ul, 0x719501eeul ); *r = *a; secp256k1_fe_mul(&r->x, &r->x, &beta); } #endif static int secp256k1_gej_has_quad_y_var(const secp256k1_gej *a) { secp256k1_fe yz; if (a->infinity) { return 0; } /* We rely on the fact that the Jacobi symbol of 1 / a->z^3 is the same as * that of a->z. Thus a->y / a->z^3 is a quadratic residue iff a->y * a->z is */ secp256k1_fe_mul(&yz, &a->y, &a->z); return secp256k1_fe_is_quad_var(&yz); } +static int secp256k1_ge_is_in_correct_subgroup(const secp256k1_ge* ge) { +#ifdef EXHAUSTIVE_TEST_ORDER + secp256k1_gej out; + int i; + + /* A very simple EC multiplication ladder that avoids a dependecy on ecmult. */ + secp256k1_gej_set_infinity(&out); + for (i = 0; i < 32; ++i) { + secp256k1_gej_double_var(&out, &out, NULL); + if ((((uint32_t)EXHAUSTIVE_TEST_ORDER) >> (31 - i)) & 1) { + secp256k1_gej_add_ge_var(&out, &out, ge, NULL); + } + } + return secp256k1_gej_is_infinity(&out); +#else + (void)ge; + /* The real secp256k1 group has cofactor 1, so the subgroup is the entire curve. */ + return 1; +#endif +} + #endif /* SECP256K1_GROUP_IMPL_H */ diff --git a/src/secp256k1/src/modules/extrakeys/main_impl.h b/src/secp256k1/src/modules/extrakeys/main_impl.h index d31921535..109080a84 100644 --- a/src/secp256k1/src/modules/extrakeys/main_impl.h +++ b/src/secp256k1/src/modules/extrakeys/main_impl.h @@ -1,248 +1,251 @@ /********************************************************************** * Copyright (c) 2020 Jonas Nick * * Distributed under the MIT software license, see the accompanying * * file COPYING or http://www.opensource.org/licenses/mit-license.php.* **********************************************************************/ #ifndef _SECP256K1_MODULE_EXTRAKEYS_MAIN_ #define _SECP256K1_MODULE_EXTRAKEYS_MAIN_ #include "include/secp256k1.h" #include "include/secp256k1_extrakeys.h" static SECP256K1_INLINE int secp256k1_xonly_pubkey_load(const secp256k1_context* ctx, secp256k1_ge *ge, const secp256k1_xonly_pubkey *pubkey) { return secp256k1_pubkey_load(ctx, ge, (const secp256k1_pubkey *) pubkey); } static SECP256K1_INLINE void secp256k1_xonly_pubkey_save(secp256k1_xonly_pubkey *pubkey, secp256k1_ge *ge) { secp256k1_pubkey_save((secp256k1_pubkey *) pubkey, ge); } int secp256k1_xonly_pubkey_parse(const secp256k1_context* ctx, secp256k1_xonly_pubkey *pubkey, const unsigned char *input32) { secp256k1_ge pk; secp256k1_fe x; VERIFY_CHECK(ctx != NULL); ARG_CHECK(pubkey != NULL); memset(pubkey, 0, sizeof(*pubkey)); ARG_CHECK(input32 != NULL); if (!secp256k1_fe_set_b32(&x, input32)) { return 0; } if (!secp256k1_ge_set_xo_var(&pk, &x, 0)) { return 0; } + if (!secp256k1_ge_is_in_correct_subgroup(&pk)) { + return 0; + } secp256k1_xonly_pubkey_save(pubkey, &pk); return 1; } int secp256k1_xonly_pubkey_serialize(const secp256k1_context* ctx, unsigned char *output32, const secp256k1_xonly_pubkey *pubkey) { secp256k1_ge pk; VERIFY_CHECK(ctx != NULL); ARG_CHECK(output32 != NULL); memset(output32, 0, 32); ARG_CHECK(pubkey != NULL); if (!secp256k1_xonly_pubkey_load(ctx, &pk, pubkey)) { return 0; } secp256k1_fe_get_b32(output32, &pk.x); return 1; } /** Keeps a group element as is if it has an even Y and otherwise negates it. * y_parity is set to 0 in the former case and to 1 in the latter case. * Requires that the coordinates of r are normalized. */ static int secp256k1_extrakeys_ge_even_y(secp256k1_ge *r) { int y_parity = 0; VERIFY_CHECK(!secp256k1_ge_is_infinity(r)); if (secp256k1_fe_is_odd(&r->y)) { secp256k1_fe_negate(&r->y, &r->y, 1); y_parity = 1; } return y_parity; } int secp256k1_xonly_pubkey_from_pubkey(const secp256k1_context* ctx, secp256k1_xonly_pubkey *xonly_pubkey, int *pk_parity, const secp256k1_pubkey *pubkey) { secp256k1_ge pk; int tmp; VERIFY_CHECK(ctx != NULL); ARG_CHECK(xonly_pubkey != NULL); ARG_CHECK(pubkey != NULL); if (!secp256k1_pubkey_load(ctx, &pk, pubkey)) { return 0; } tmp = secp256k1_extrakeys_ge_even_y(&pk); if (pk_parity != NULL) { *pk_parity = tmp; } secp256k1_xonly_pubkey_save(xonly_pubkey, &pk); return 1; } int secp256k1_xonly_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *output_pubkey, const secp256k1_xonly_pubkey *internal_pubkey, const unsigned char *tweak32) { secp256k1_ge pk; VERIFY_CHECK(ctx != NULL); ARG_CHECK(output_pubkey != NULL); memset(output_pubkey, 0, sizeof(*output_pubkey)); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(internal_pubkey != NULL); ARG_CHECK(tweak32 != NULL); if (!secp256k1_xonly_pubkey_load(ctx, &pk, internal_pubkey) || !secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &pk, tweak32)) { return 0; } secp256k1_pubkey_save(output_pubkey, &pk); return 1; } int secp256k1_xonly_pubkey_tweak_add_check(const secp256k1_context* ctx, const unsigned char *tweaked_pubkey32, int tweaked_pk_parity, const secp256k1_xonly_pubkey *internal_pubkey, const unsigned char *tweak32) { secp256k1_ge pk; unsigned char pk_expected32[32]; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(internal_pubkey != NULL); ARG_CHECK(tweaked_pubkey32 != NULL); ARG_CHECK(tweak32 != NULL); if (!secp256k1_xonly_pubkey_load(ctx, &pk, internal_pubkey) || !secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &pk, tweak32)) { return 0; } secp256k1_fe_normalize_var(&pk.x); secp256k1_fe_normalize_var(&pk.y); secp256k1_fe_get_b32(pk_expected32, &pk.x); return memcmp(&pk_expected32, tweaked_pubkey32, 32) == 0 && secp256k1_fe_is_odd(&pk.y) == tweaked_pk_parity; } static void secp256k1_keypair_save(secp256k1_keypair *keypair, const secp256k1_scalar *sk, secp256k1_ge *pk) { secp256k1_scalar_get_b32(&keypair->data[0], sk); secp256k1_pubkey_save((secp256k1_pubkey *)&keypair->data[32], pk); } static int secp256k1_keypair_seckey_load(const secp256k1_context* ctx, secp256k1_scalar *sk, const secp256k1_keypair *keypair) { int ret; ret = secp256k1_scalar_set_b32_seckey(sk, &keypair->data[0]); /* We can declassify ret here because sk is only zero if a keypair function * failed (which zeroes the keypair) and its return value is ignored. */ secp256k1_declassify(ctx, &ret, sizeof(ret)); ARG_CHECK(ret); return ret; } /* Load a keypair into pk and sk (if non-NULL). This function declassifies pk * and ARG_CHECKs that the keypair is not invalid. It always initializes sk and * pk with dummy values. */ static int secp256k1_keypair_load(const secp256k1_context* ctx, secp256k1_scalar *sk, secp256k1_ge *pk, const secp256k1_keypair *keypair) { int ret; const secp256k1_pubkey *pubkey = (const secp256k1_pubkey *)&keypair->data[32]; /* Need to declassify the pubkey because pubkey_load ARG_CHECKs if it's * invalid. */ secp256k1_declassify(ctx, pubkey, sizeof(*pubkey)); ret = secp256k1_pubkey_load(ctx, pk, pubkey); if (sk != NULL) { ret = ret && secp256k1_keypair_seckey_load(ctx, sk, keypair); } if (!ret) { *pk = secp256k1_ge_const_g; if (sk != NULL) { *sk = secp256k1_scalar_one; } } return ret; } int secp256k1_keypair_create(const secp256k1_context* ctx, secp256k1_keypair *keypair, const unsigned char *seckey32) { secp256k1_scalar sk; secp256k1_ge pk; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(keypair != NULL); memset(keypair, 0, sizeof(*keypair)); ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); ARG_CHECK(seckey32 != NULL); ret = secp256k1_ec_pubkey_create_helper(&ctx->ecmult_gen_ctx, &sk, &pk, seckey32); secp256k1_keypair_save(keypair, &sk, &pk); memczero(keypair, sizeof(*keypair), !ret); secp256k1_scalar_clear(&sk); return ret; } int secp256k1_keypair_pub(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const secp256k1_keypair *keypair) { VERIFY_CHECK(ctx != NULL); ARG_CHECK(pubkey != NULL); memset(pubkey, 0, sizeof(*pubkey)); ARG_CHECK(keypair != NULL); memcpy(pubkey->data, &keypair->data[32], sizeof(*pubkey)); return 1; } int secp256k1_keypair_xonly_pub(const secp256k1_context* ctx, secp256k1_xonly_pubkey *pubkey, int *pk_parity, const secp256k1_keypair *keypair) { secp256k1_ge pk; int tmp; VERIFY_CHECK(ctx != NULL); ARG_CHECK(pubkey != NULL); memset(pubkey, 0, sizeof(*pubkey)); ARG_CHECK(keypair != NULL); if (!secp256k1_keypair_load(ctx, NULL, &pk, keypair)) { return 0; } tmp = secp256k1_extrakeys_ge_even_y(&pk); if (pk_parity != NULL) { *pk_parity = tmp; } secp256k1_xonly_pubkey_save(pubkey, &pk); return 1; } int secp256k1_keypair_xonly_tweak_add(const secp256k1_context* ctx, secp256k1_keypair *keypair, const unsigned char *tweak32) { secp256k1_ge pk; secp256k1_scalar sk; int y_parity; int ret; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(keypair != NULL); ARG_CHECK(tweak32 != NULL); ret = secp256k1_keypair_load(ctx, &sk, &pk, keypair); memset(keypair, 0, sizeof(*keypair)); y_parity = secp256k1_extrakeys_ge_even_y(&pk); if (y_parity == 1) { secp256k1_scalar_negate(&sk, &sk); } ret &= secp256k1_ec_seckey_tweak_add_helper(&sk, tweak32); ret &= secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &pk, tweak32); secp256k1_declassify(ctx, &ret, sizeof(ret)); if (ret) { secp256k1_keypair_save(keypair, &sk, &pk); } secp256k1_scalar_clear(&sk); return ret; } #endif diff --git a/src/secp256k1/src/secp256k1.c b/src/secp256k1/src/secp256k1.c index 544125400..11cc771aa 100644 --- a/src/secp256k1/src/secp256k1.c +++ b/src/secp256k1/src/secp256k1.c @@ -1,776 +1,779 @@ /********************************************************************** * Copyright (c) 2013-2015 Pieter Wuille * * Distributed under the MIT software license, see the accompanying * * file COPYING or http://www.opensource.org/licenses/mit-license.php.* **********************************************************************/ #include "include/secp256k1.h" #include "include/secp256k1_preallocated.h" #include "assumptions.h" #include "util.h" #include "num_impl.h" #include "field_impl.h" #include "scalar_impl.h" #include "group_impl.h" #include "ecmult_impl.h" #include "ecmult_const_impl.h" #include "ecmult_gen_impl.h" #include "ecdsa_impl.h" #include "eckey_impl.h" #include "hash_impl.h" #include "scratch_impl.h" #if defined(VALGRIND) # include #endif #define ARG_CHECK(cond) do { \ if (EXPECT(!(cond), 0)) { \ secp256k1_callback_call(&ctx->illegal_callback, #cond); \ return 0; \ } \ } while(0) #define ARG_CHECK_NO_RETURN(cond) do { \ if (EXPECT(!(cond), 0)) { \ secp256k1_callback_call(&ctx->illegal_callback, #cond); \ } \ } while(0) #ifndef USE_EXTERNAL_DEFAULT_CALLBACKS #include #include static void secp256k1_default_illegal_callback_fn(const char* str, void* data) { (void)data; fprintf(stderr, "[libsecp256k1] illegal argument: %s\n", str); abort(); } static void secp256k1_default_error_callback_fn(const char* str, void* data) { (void)data; fprintf(stderr, "[libsecp256k1] internal consistency check failed: %s\n", str); abort(); } #else void secp256k1_default_illegal_callback_fn(const char* str, void* data); void secp256k1_default_error_callback_fn(const char* str, void* data); #endif static const secp256k1_callback default_illegal_callback = { secp256k1_default_illegal_callback_fn, NULL }; static const secp256k1_callback default_error_callback = { secp256k1_default_error_callback_fn, NULL }; struct secp256k1_context_struct { secp256k1_ecmult_context ecmult_ctx; secp256k1_ecmult_gen_context ecmult_gen_ctx; secp256k1_callback illegal_callback; secp256k1_callback error_callback; int declassify; }; static const secp256k1_context secp256k1_context_no_precomp_ = { { 0 }, { 0 }, { secp256k1_default_illegal_callback_fn, 0 }, { secp256k1_default_error_callback_fn, 0 }, 0 }; const secp256k1_context *secp256k1_context_no_precomp = &secp256k1_context_no_precomp_; size_t secp256k1_context_preallocated_size(unsigned int flags) { size_t ret = ROUND_TO_ALIGN(sizeof(secp256k1_context)); if (EXPECT((flags & SECP256K1_FLAGS_TYPE_MASK) != SECP256K1_FLAGS_TYPE_CONTEXT, 0)) { secp256k1_callback_call(&default_illegal_callback, "Invalid flags"); return 0; } if (flags & SECP256K1_FLAGS_BIT_CONTEXT_SIGN) { ret += SECP256K1_ECMULT_GEN_CONTEXT_PREALLOCATED_SIZE; } if (flags & SECP256K1_FLAGS_BIT_CONTEXT_VERIFY) { ret += SECP256K1_ECMULT_CONTEXT_PREALLOCATED_SIZE; } return ret; } size_t secp256k1_context_preallocated_clone_size(const secp256k1_context* ctx) { size_t ret = ROUND_TO_ALIGN(sizeof(secp256k1_context)); VERIFY_CHECK(ctx != NULL); if (secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)) { ret += SECP256K1_ECMULT_GEN_CONTEXT_PREALLOCATED_SIZE; } if (secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)) { ret += SECP256K1_ECMULT_CONTEXT_PREALLOCATED_SIZE; } return ret; } secp256k1_context* secp256k1_context_preallocated_create(void* prealloc, unsigned int flags) { void* const base = prealloc; size_t prealloc_size; secp256k1_context* ret; VERIFY_CHECK(prealloc != NULL); prealloc_size = secp256k1_context_preallocated_size(flags); ret = (secp256k1_context*)manual_alloc(&prealloc, sizeof(secp256k1_context), base, prealloc_size); ret->illegal_callback = default_illegal_callback; ret->error_callback = default_error_callback; if (EXPECT((flags & SECP256K1_FLAGS_TYPE_MASK) != SECP256K1_FLAGS_TYPE_CONTEXT, 0)) { secp256k1_callback_call(&ret->illegal_callback, "Invalid flags"); return NULL; } secp256k1_ecmult_context_init(&ret->ecmult_ctx); secp256k1_ecmult_gen_context_init(&ret->ecmult_gen_ctx); if (flags & SECP256K1_FLAGS_BIT_CONTEXT_SIGN) { secp256k1_ecmult_gen_context_build(&ret->ecmult_gen_ctx, &prealloc); } if (flags & SECP256K1_FLAGS_BIT_CONTEXT_VERIFY) { secp256k1_ecmult_context_build(&ret->ecmult_ctx, &prealloc); } ret->declassify = !!(flags & SECP256K1_FLAGS_BIT_CONTEXT_DECLASSIFY); return (secp256k1_context*) ret; } secp256k1_context* secp256k1_context_create(unsigned int flags) { size_t const prealloc_size = secp256k1_context_preallocated_size(flags); secp256k1_context* ctx = (secp256k1_context*)checked_malloc(&default_error_callback, prealloc_size); if (EXPECT(secp256k1_context_preallocated_create(ctx, flags) == NULL, 0)) { free(ctx); return NULL; } return ctx; } secp256k1_context* secp256k1_context_preallocated_clone(const secp256k1_context* ctx, void* prealloc) { size_t prealloc_size; secp256k1_context* ret; VERIFY_CHECK(ctx != NULL); ARG_CHECK(prealloc != NULL); prealloc_size = secp256k1_context_preallocated_clone_size(ctx); ret = (secp256k1_context*)prealloc; memcpy(ret, ctx, prealloc_size); secp256k1_ecmult_gen_context_finalize_memcpy(&ret->ecmult_gen_ctx, &ctx->ecmult_gen_ctx); secp256k1_ecmult_context_finalize_memcpy(&ret->ecmult_ctx, &ctx->ecmult_ctx); return ret; } secp256k1_context* secp256k1_context_clone(const secp256k1_context* ctx) { secp256k1_context* ret; size_t prealloc_size; VERIFY_CHECK(ctx != NULL); prealloc_size = secp256k1_context_preallocated_clone_size(ctx); ret = (secp256k1_context*)checked_malloc(&ctx->error_callback, prealloc_size); ret = secp256k1_context_preallocated_clone(ctx, ret); return ret; } void secp256k1_context_preallocated_destroy(secp256k1_context* ctx) { ARG_CHECK_NO_RETURN(ctx != secp256k1_context_no_precomp); if (ctx != NULL) { secp256k1_ecmult_context_clear(&ctx->ecmult_ctx); secp256k1_ecmult_gen_context_clear(&ctx->ecmult_gen_ctx); } } void secp256k1_context_destroy(secp256k1_context* ctx) { if (ctx != NULL) { secp256k1_context_preallocated_destroy(ctx); free(ctx); } } void secp256k1_context_set_illegal_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) { ARG_CHECK_NO_RETURN(ctx != secp256k1_context_no_precomp); if (fun == NULL) { fun = secp256k1_default_illegal_callback_fn; } ctx->illegal_callback.fn = fun; ctx->illegal_callback.data = data; } void secp256k1_context_set_error_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) { ARG_CHECK_NO_RETURN(ctx != secp256k1_context_no_precomp); if (fun == NULL) { fun = secp256k1_default_error_callback_fn; } ctx->error_callback.fn = fun; ctx->error_callback.data = data; } secp256k1_scratch_space* secp256k1_scratch_space_create(const secp256k1_context* ctx, size_t max_size) { VERIFY_CHECK(ctx != NULL); return secp256k1_scratch_create(&ctx->error_callback, max_size); } void secp256k1_scratch_space_destroy(const secp256k1_context *ctx, secp256k1_scratch_space* scratch) { VERIFY_CHECK(ctx != NULL); secp256k1_scratch_destroy(&ctx->error_callback, scratch); } /* Mark memory as no-longer-secret for the purpose of analysing constant-time behaviour * of the software. This is setup for use with valgrind but could be substituted with * the appropriate instrumentation for other analysis tools. */ static SECP256K1_INLINE void secp256k1_declassify(const secp256k1_context* ctx, const void *p, size_t len) { #if defined(VALGRIND) if (EXPECT(ctx->declassify,0)) VALGRIND_MAKE_MEM_DEFINED(p, len); #else (void)ctx; (void)p; (void)len; #endif } static int secp256k1_pubkey_load(const secp256k1_context* ctx, secp256k1_ge* ge, const secp256k1_pubkey* pubkey) { if (sizeof(secp256k1_ge_storage) == 64) { /* When the secp256k1_ge_storage type is exactly 64 byte, use its * representation inside secp256k1_pubkey, as conversion is very fast. * Note that secp256k1_pubkey_save must use the same representation. */ secp256k1_ge_storage s; memcpy(&s, &pubkey->data[0], sizeof(s)); secp256k1_ge_from_storage(ge, &s); } else { /* Otherwise, fall back to 32-byte big endian for X and Y. */ secp256k1_fe x, y; secp256k1_fe_set_b32(&x, pubkey->data); secp256k1_fe_set_b32(&y, pubkey->data + 32); secp256k1_ge_set_xy(ge, &x, &y); } ARG_CHECK(!secp256k1_fe_is_zero(&ge->x)); return 1; } static void secp256k1_pubkey_save(secp256k1_pubkey* pubkey, secp256k1_ge* ge) { if (sizeof(secp256k1_ge_storage) == 64) { secp256k1_ge_storage s; secp256k1_ge_to_storage(&s, ge); memcpy(&pubkey->data[0], &s, sizeof(s)); } else { VERIFY_CHECK(!secp256k1_ge_is_infinity(ge)); secp256k1_fe_normalize_var(&ge->x); secp256k1_fe_normalize_var(&ge->y); secp256k1_fe_get_b32(pubkey->data, &ge->x); secp256k1_fe_get_b32(pubkey->data + 32, &ge->y); } } int secp256k1_ec_pubkey_parse(const secp256k1_context* ctx, secp256k1_pubkey* pubkey, const unsigned char *input, size_t inputlen) { secp256k1_ge Q; VERIFY_CHECK(ctx != NULL); ARG_CHECK(pubkey != NULL); memset(pubkey, 0, sizeof(*pubkey)); ARG_CHECK(input != NULL); if (!secp256k1_eckey_pubkey_parse(&Q, input, inputlen)) { return 0; } + if (!secp256k1_ge_is_in_correct_subgroup(&Q)) { + return 0; + } secp256k1_pubkey_save(pubkey, &Q); secp256k1_ge_clear(&Q); return 1; } int secp256k1_ec_pubkey_serialize(const secp256k1_context* ctx, unsigned char *output, size_t *outputlen, const secp256k1_pubkey* pubkey, unsigned int flags) { secp256k1_ge Q; size_t len; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(outputlen != NULL); ARG_CHECK(*outputlen >= ((flags & SECP256K1_FLAGS_BIT_COMPRESSION) ? 33u : 65u)); len = *outputlen; *outputlen = 0; ARG_CHECK(output != NULL); memset(output, 0, len); ARG_CHECK(pubkey != NULL); ARG_CHECK((flags & SECP256K1_FLAGS_TYPE_MASK) == SECP256K1_FLAGS_TYPE_COMPRESSION); if (secp256k1_pubkey_load(ctx, &Q, pubkey)) { ret = secp256k1_eckey_pubkey_serialize(&Q, output, &len, flags & SECP256K1_FLAGS_BIT_COMPRESSION); if (ret) { *outputlen = len; } } return ret; } static void secp256k1_ecdsa_signature_load(const secp256k1_context* ctx, secp256k1_scalar* r, secp256k1_scalar* s, const secp256k1_ecdsa_signature* sig) { (void)ctx; if (sizeof(secp256k1_scalar) == 32) { /* When the secp256k1_scalar type is exactly 32 byte, use its * representation inside secp256k1_ecdsa_signature, as conversion is very fast. * Note that secp256k1_ecdsa_signature_save must use the same representation. */ memcpy(r, &sig->data[0], 32); memcpy(s, &sig->data[32], 32); } else { secp256k1_scalar_set_b32(r, &sig->data[0], NULL); secp256k1_scalar_set_b32(s, &sig->data[32], NULL); } } static void secp256k1_ecdsa_signature_save(secp256k1_ecdsa_signature* sig, const secp256k1_scalar* r, const secp256k1_scalar* s) { if (sizeof(secp256k1_scalar) == 32) { memcpy(&sig->data[0], r, 32); memcpy(&sig->data[32], s, 32); } else { secp256k1_scalar_get_b32(&sig->data[0], r); secp256k1_scalar_get_b32(&sig->data[32], s); } } int secp256k1_ecdsa_signature_parse_der(const secp256k1_context* ctx, secp256k1_ecdsa_signature* sig, const unsigned char *input, size_t inputlen) { secp256k1_scalar r, s; VERIFY_CHECK(ctx != NULL); ARG_CHECK(sig != NULL); ARG_CHECK(input != NULL); if (secp256k1_ecdsa_sig_parse(&r, &s, input, inputlen)) { secp256k1_ecdsa_signature_save(sig, &r, &s); return 1; } else { memset(sig, 0, sizeof(*sig)); return 0; } } int secp256k1_ecdsa_signature_parse_compact(const secp256k1_context* ctx, secp256k1_ecdsa_signature* sig, const unsigned char *input64) { secp256k1_scalar r, s; int ret = 1; int overflow = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(sig != NULL); ARG_CHECK(input64 != NULL); secp256k1_scalar_set_b32(&r, &input64[0], &overflow); ret &= !overflow; secp256k1_scalar_set_b32(&s, &input64[32], &overflow); ret &= !overflow; if (ret) { secp256k1_ecdsa_signature_save(sig, &r, &s); } else { memset(sig, 0, sizeof(*sig)); } return ret; } int secp256k1_ecdsa_signature_serialize_der(const secp256k1_context* ctx, unsigned char *output, size_t *outputlen, const secp256k1_ecdsa_signature* sig) { secp256k1_scalar r, s; VERIFY_CHECK(ctx != NULL); ARG_CHECK(output != NULL); ARG_CHECK(outputlen != NULL); ARG_CHECK(sig != NULL); secp256k1_ecdsa_signature_load(ctx, &r, &s, sig); return secp256k1_ecdsa_sig_serialize(output, outputlen, &r, &s); } int secp256k1_ecdsa_signature_serialize_compact(const secp256k1_context* ctx, unsigned char *output64, const secp256k1_ecdsa_signature* sig) { secp256k1_scalar r, s; VERIFY_CHECK(ctx != NULL); ARG_CHECK(output64 != NULL); ARG_CHECK(sig != NULL); secp256k1_ecdsa_signature_load(ctx, &r, &s, sig); secp256k1_scalar_get_b32(&output64[0], &r); secp256k1_scalar_get_b32(&output64[32], &s); return 1; } int secp256k1_ecdsa_signature_normalize(const secp256k1_context* ctx, secp256k1_ecdsa_signature *sigout, const secp256k1_ecdsa_signature *sigin) { secp256k1_scalar r, s; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(sigin != NULL); secp256k1_ecdsa_signature_load(ctx, &r, &s, sigin); ret = secp256k1_scalar_is_high(&s); if (sigout != NULL) { if (ret) { secp256k1_scalar_negate(&s, &s); } secp256k1_ecdsa_signature_save(sigout, &r, &s); } return ret; } int secp256k1_ecdsa_verify(const secp256k1_context* ctx, const secp256k1_ecdsa_signature *sig, const unsigned char *msg32, const secp256k1_pubkey *pubkey) { secp256k1_ge q; secp256k1_scalar r, s; secp256k1_scalar m; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(msg32 != NULL); ARG_CHECK(sig != NULL); ARG_CHECK(pubkey != NULL); secp256k1_scalar_set_b32(&m, msg32, NULL); secp256k1_ecdsa_signature_load(ctx, &r, &s, sig); return (!secp256k1_scalar_is_high(&s) && secp256k1_pubkey_load(ctx, &q, pubkey) && secp256k1_ecdsa_sig_verify(&ctx->ecmult_ctx, &r, &s, &q, &m)); } static SECP256K1_INLINE void buffer_append(unsigned char *buf, unsigned int *offset, const void *data, unsigned int len) { memcpy(buf + *offset, data, len); *offset += len; } static int nonce_function_rfc6979(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, const unsigned char *algo16, void *data, unsigned int counter) { unsigned char keydata[112]; unsigned int offset = 0; secp256k1_rfc6979_hmac_sha256 rng; unsigned int i; /* We feed a byte array to the PRNG as input, consisting of: * - the private key (32 bytes) and message (32 bytes), see RFC 6979 3.2d. * - optionally 32 extra bytes of data, see RFC 6979 3.6 Additional Data. * - optionally 16 extra bytes with the algorithm name. * Because the arguments have distinct fixed lengths it is not possible for * different argument mixtures to emulate each other and result in the same * nonces. */ buffer_append(keydata, &offset, key32, 32); buffer_append(keydata, &offset, msg32, 32); if (data != NULL) { buffer_append(keydata, &offset, data, 32); } if (algo16 != NULL) { buffer_append(keydata, &offset, algo16, 16); } secp256k1_rfc6979_hmac_sha256_initialize(&rng, keydata, offset); memset(keydata, 0, sizeof(keydata)); for (i = 0; i <= counter; i++) { secp256k1_rfc6979_hmac_sha256_generate(&rng, nonce32, 32); } secp256k1_rfc6979_hmac_sha256_finalize(&rng); return 1; } const secp256k1_nonce_function secp256k1_nonce_function_rfc6979 = nonce_function_rfc6979; const secp256k1_nonce_function secp256k1_nonce_function_default = nonce_function_rfc6979; static int secp256k1_ecdsa_sign_inner(const secp256k1_context* ctx, secp256k1_scalar* r, secp256k1_scalar* s, int* recid, const unsigned char *msg32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const unsigned char algo16[17], const void* noncedata) { secp256k1_scalar sec, non, msg; int ret = 0; int is_sec_valid; unsigned char nonce32[32]; unsigned int count = 0; /* Default initialization here is important so we won't pass uninit values to the cmov in the end */ *r = secp256k1_scalar_zero; *s = secp256k1_scalar_zero; if (recid) { *recid = 0; } if (noncefp == NULL) { noncefp = secp256k1_nonce_function_default; } /* Fail if the secret key is invalid. */ is_sec_valid = secp256k1_scalar_set_b32_seckey(&sec, seckey); secp256k1_scalar_cmov(&sec, &secp256k1_scalar_one, !is_sec_valid); secp256k1_scalar_set_b32(&msg, msg32, NULL); while (1) { int is_nonce_valid; ret = !!noncefp(nonce32, msg32, seckey, algo16, (void*)noncedata, count); if (!ret) { break; } is_nonce_valid = secp256k1_scalar_set_b32_seckey(&non, nonce32); /* The nonce is still secret here, but it being invalid is is less likely than 1:2^255. */ secp256k1_declassify(ctx, &is_nonce_valid, sizeof(is_nonce_valid)); if (is_nonce_valid) { ret = secp256k1_ecdsa_sig_sign(&ctx->ecmult_gen_ctx, r, s, &sec, &msg, &non, recid); /* The final signature is no longer a secret, nor is the fact that we were successful or not. */ secp256k1_declassify(ctx, &ret, sizeof(ret)); if (ret) { break; } } count++; } /* We don't want to declassify is_sec_valid and therefore the range of * seckey. As a result is_sec_valid is included in ret only after ret was * used as a branching variable. */ ret &= is_sec_valid; memset(nonce32, 0, 32); secp256k1_scalar_clear(&msg); secp256k1_scalar_clear(&non); secp256k1_scalar_clear(&sec); secp256k1_scalar_cmov(r, &secp256k1_scalar_zero, !ret); secp256k1_scalar_cmov(s, &secp256k1_scalar_zero, !ret); if (recid) { const int zero = 0; secp256k1_int_cmov(recid, &zero, !ret); } return ret; } int secp256k1_ecdsa_sign(const secp256k1_context* ctx, secp256k1_ecdsa_signature *signature, const unsigned char *msg32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) { secp256k1_scalar r, s; int ret; const unsigned char secp256k1_ecdsa_der_algo16[17] = "ECDSA+DER "; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); ARG_CHECK(msg32 != NULL); ARG_CHECK(signature != NULL); ARG_CHECK(seckey != NULL); ret = secp256k1_ecdsa_sign_inner(ctx, &r, &s, NULL, msg32, seckey, noncefp, secp256k1_ecdsa_der_algo16, noncedata); secp256k1_ecdsa_signature_save(signature, &r, &s); return ret; } int secp256k1_ec_seckey_verify(const secp256k1_context* ctx, const unsigned char *seckey) { secp256k1_scalar sec; int ret; VERIFY_CHECK(ctx != NULL); ARG_CHECK(seckey != NULL); ret = secp256k1_scalar_set_b32_seckey(&sec, seckey); secp256k1_scalar_clear(&sec); return ret; } static int secp256k1_ec_pubkey_create_helper(const secp256k1_ecmult_gen_context *ecmult_gen_ctx, secp256k1_scalar *seckey_scalar, secp256k1_ge *p, const unsigned char *seckey) { secp256k1_gej pj; int ret; ret = secp256k1_scalar_set_b32_seckey(seckey_scalar, seckey); secp256k1_scalar_cmov(seckey_scalar, &secp256k1_scalar_one, !ret); secp256k1_ecmult_gen(ecmult_gen_ctx, &pj, seckey_scalar); secp256k1_ge_set_gej(p, &pj); return ret; } int secp256k1_ec_pubkey_create(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *seckey) { secp256k1_ge p; secp256k1_scalar seckey_scalar; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(pubkey != NULL); memset(pubkey, 0, sizeof(*pubkey)); ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); ARG_CHECK(seckey != NULL); ret = secp256k1_ec_pubkey_create_helper(&ctx->ecmult_gen_ctx, &seckey_scalar, &p, seckey); secp256k1_pubkey_save(pubkey, &p); memczero(pubkey, sizeof(*pubkey), !ret); secp256k1_scalar_clear(&seckey_scalar); return ret; } int secp256k1_ec_seckey_negate(const secp256k1_context* ctx, unsigned char *seckey) { secp256k1_scalar sec; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(seckey != NULL); ret = secp256k1_scalar_set_b32_seckey(&sec, seckey); secp256k1_scalar_cmov(&sec, &secp256k1_scalar_zero, !ret); secp256k1_scalar_negate(&sec, &sec); secp256k1_scalar_get_b32(seckey, &sec); secp256k1_scalar_clear(&sec); return ret; } int secp256k1_ec_privkey_negate(const secp256k1_context* ctx, unsigned char *seckey) { return secp256k1_ec_seckey_negate(ctx, seckey); } int secp256k1_ec_pubkey_negate(const secp256k1_context* ctx, secp256k1_pubkey *pubkey) { int ret = 0; secp256k1_ge p; VERIFY_CHECK(ctx != NULL); ARG_CHECK(pubkey != NULL); ret = secp256k1_pubkey_load(ctx, &p, pubkey); memset(pubkey, 0, sizeof(*pubkey)); if (ret) { secp256k1_ge_neg(&p, &p); secp256k1_pubkey_save(pubkey, &p); } return ret; } static int secp256k1_ec_seckey_tweak_add_helper(secp256k1_scalar *sec, const unsigned char *tweak) { secp256k1_scalar term; int overflow = 0; int ret = 0; secp256k1_scalar_set_b32(&term, tweak, &overflow); ret = (!overflow) & secp256k1_eckey_privkey_tweak_add(sec, &term); secp256k1_scalar_clear(&term); return ret; } int secp256k1_ec_seckey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { secp256k1_scalar sec; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(seckey != NULL); ARG_CHECK(tweak != NULL); ret = secp256k1_scalar_set_b32_seckey(&sec, seckey); ret &= secp256k1_ec_seckey_tweak_add_helper(&sec, tweak); secp256k1_scalar_cmov(&sec, &secp256k1_scalar_zero, !ret); secp256k1_scalar_get_b32(seckey, &sec); secp256k1_scalar_clear(&sec); return ret; } int secp256k1_ec_privkey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { return secp256k1_ec_seckey_tweak_add(ctx, seckey, tweak); } static int secp256k1_ec_pubkey_tweak_add_helper(const secp256k1_ecmult_context* ecmult_ctx, secp256k1_ge *p, const unsigned char *tweak) { secp256k1_scalar term; int overflow = 0; secp256k1_scalar_set_b32(&term, tweak, &overflow); return !overflow && secp256k1_eckey_pubkey_tweak_add(ecmult_ctx, p, &term); } int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) { secp256k1_ge p; int ret = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(pubkey != NULL); ARG_CHECK(tweak != NULL); ret = secp256k1_pubkey_load(ctx, &p, pubkey); memset(pubkey, 0, sizeof(*pubkey)); ret = ret && secp256k1_ec_pubkey_tweak_add_helper(&ctx->ecmult_ctx, &p, tweak); if (ret) { secp256k1_pubkey_save(pubkey, &p); } return ret; } int secp256k1_ec_seckey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { secp256k1_scalar factor; secp256k1_scalar sec; int ret = 0; int overflow = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(seckey != NULL); ARG_CHECK(tweak != NULL); secp256k1_scalar_set_b32(&factor, tweak, &overflow); ret = secp256k1_scalar_set_b32_seckey(&sec, seckey); ret &= (!overflow) & secp256k1_eckey_privkey_tweak_mul(&sec, &factor); secp256k1_scalar_cmov(&sec, &secp256k1_scalar_zero, !ret); secp256k1_scalar_get_b32(seckey, &sec); secp256k1_scalar_clear(&sec); secp256k1_scalar_clear(&factor); return ret; } int secp256k1_ec_privkey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { return secp256k1_ec_seckey_tweak_mul(ctx, seckey, tweak); } int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) { secp256k1_ge p; secp256k1_scalar factor; int ret = 0; int overflow = 0; VERIFY_CHECK(ctx != NULL); ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); ARG_CHECK(pubkey != NULL); ARG_CHECK(tweak != NULL); secp256k1_scalar_set_b32(&factor, tweak, &overflow); ret = !overflow && secp256k1_pubkey_load(ctx, &p, pubkey); memset(pubkey, 0, sizeof(*pubkey)); if (ret) { if (secp256k1_eckey_pubkey_tweak_mul(&ctx->ecmult_ctx, &p, &factor)) { secp256k1_pubkey_save(pubkey, &p); } else { ret = 0; } } return ret; } int secp256k1_context_randomize(secp256k1_context* ctx, const unsigned char *seed32) { VERIFY_CHECK(ctx != NULL); if (secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)) { secp256k1_ecmult_gen_blind(&ctx->ecmult_gen_ctx, seed32); } return 1; } int secp256k1_ec_pubkey_combine(const secp256k1_context* ctx, secp256k1_pubkey *pubnonce, const secp256k1_pubkey * const *pubnonces, size_t n) { size_t i; secp256k1_gej Qj; secp256k1_ge Q; ARG_CHECK(pubnonce != NULL); memset(pubnonce, 0, sizeof(*pubnonce)); ARG_CHECK(n >= 1); ARG_CHECK(pubnonces != NULL); secp256k1_gej_set_infinity(&Qj); for (i = 0; i < n; i++) { secp256k1_pubkey_load(ctx, &Q, pubnonces[i]); secp256k1_gej_add_ge(&Qj, &Qj, &Q); } if (secp256k1_gej_is_infinity(&Qj)) { return 0; } secp256k1_ge_set_gej(&Q, &Qj); secp256k1_pubkey_save(pubnonce, &Q); return 1; } #ifdef ENABLE_MODULE_ECDH # include "modules/ecdh/main_impl.h" #endif #ifdef ENABLE_MODULE_MULTISET # include "modules/multiset/main_impl.h" #endif #ifdef ENABLE_MODULE_RECOVERY # include "modules/recovery/main_impl.h" #endif #ifdef ENABLE_MODULE_SCHNORR # include "modules/schnorr/main_impl.h" #endif #ifdef ENABLE_MODULE_EXTRAKEYS # include "modules/extrakeys/main_impl.h" #endif #ifdef ENABLE_MODULE_SCHNORRSIG # include "modules/schnorrsig/main_impl.h" #endif