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Diffstat (limited to 'crypto/secp256k1/libsecp256k1/src/group.h')
-rw-r--r-- | crypto/secp256k1/libsecp256k1/src/group.h | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/crypto/secp256k1/libsecp256k1/src/group.h b/crypto/secp256k1/libsecp256k1/src/group.h new file mode 100644 index 000000000..89b079d5c --- /dev/null +++ b/crypto/secp256k1/libsecp256k1/src/group.h @@ -0,0 +1,141 @@ +/********************************************************************** + * 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_ +#define _SECP256K1_GROUP_ + +#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 at infinity */ +static void secp256k1_ge_set_infinity(secp256k1_ge *r); + +/** 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 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); + +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(size_t len, secp256k1_ge *r, const secp256k1_gej *a, const secp256k1_callback *cb); + +/** Set a batch of group elements equal to the inputs given in jacobian + * coordinates (with known z-ratios). zr must contain the known z-ratios such + * that mul(a[i].z, zr[i+1]) == a[i+1].z. zr[0] is ignored. */ +static void secp256k1_ge_set_table_gej_var(size_t len, secp256k1_ge *r, const secp256k1_gej *a, const secp256k1_fe *zr); + +/** 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 (jacobian) equal to the point at infinity. */ +static void secp256k1_gej_set_infinity(secp256k1_gej *r); + +/** Set a group element (jacobian) equal to the point with given X and Y coordinates. */ +static void secp256k1_gej_set_xy(secp256k1_gej *r, const secp256k1_fe *x, const secp256k1_fe *y); + +/** 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); + +/** Set r equal to the double of a. If rzr is not-NULL, r->z = a->z * *rzr (where infinity means an implicit z = 0). + * a may not be zero. Constant time. */ +static void secp256k1_gej_double_nonzero(secp256k1_gej *r, const secp256k1_gej *a, secp256k1_fe *rzr); + +/** Set r equal to the double of a. If rzr is not-NULL, 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, 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, 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. */ +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); + +#endif |