/** * \file ecp_internal.h * * \brief Function declarations for alternative implementation of elliptic curve * point arithmetic. */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ /* * References: * * [1] BERNSTEIN, Daniel J. Curve25519: new Diffie-Hellman speed records. * * * [2] CORON, Jean-S'ebastien. Resistance against differential power analysis * for elliptic curve cryptosystems. In : Cryptographic Hardware and * Embedded Systems. Springer Berlin Heidelberg, 1999. p. 292-302. * * * [3] HEDABOU, Mustapha, PINEL, Pierre, et B'EN'ETEAU, Lucien. A comb method to * render ECC resistant against Side Channel Attacks. IACR Cryptology * ePrint Archive, 2004, vol. 2004, p. 342. * * * [4] Certicom Research. SEC 2: Recommended Elliptic Curve Domain Parameters. * * * [5] HANKERSON, Darrel, MENEZES, Alfred J., VANSTONE, Scott. Guide to Elliptic * Curve Cryptography. * * [6] Digital Signature Standard (DSS), FIPS 186-4. * * * [7] Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer * Security (TLS), RFC 4492. * * * [8] * * [9] COHEN, Henri. A Course in Computational Algebraic Number Theory. * Springer Science & Business Media, 1 Aug 2000 */ #ifndef MBEDTLS_ECP_INTERNAL_H #define MBEDTLS_ECP_INTERNAL_H #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_ECP_INTERNAL_ALT) /** * \brief Indicate if the Elliptic Curve Point module extension can * handle the group. * * \param grp The pointer to the elliptic curve group that will be the * basis of the cryptographic computations. * * \return Non-zero if successful. */ unsigned char mbedtls_internal_ecp_grp_capable(const mbedtls_ecp_group *grp); /** * \brief Initialise the Elliptic Curve Point module extension. * * If mbedtls_internal_ecp_grp_capable returns true for a * group, this function has to be able to initialise the * module for it. * * This module can be a driver to a crypto hardware * accelerator, for which this could be an initialise function. * * \param grp The pointer to the group the module needs to be * initialised for. * * \return 0 if successful. */ int mbedtls_internal_ecp_init(const mbedtls_ecp_group *grp); /** * \brief Frees and deallocates the Elliptic Curve Point module * extension. * * \param grp The pointer to the group the module was initialised for. */ void mbedtls_internal_ecp_free(const mbedtls_ecp_group *grp); #if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) #if defined(MBEDTLS_ECP_RANDOMIZE_JAC_ALT) /** * \brief Randomize jacobian coordinates: * (X, Y, Z) -> (l^2 X, l^3 Y, l Z) for random l. * * \param grp Pointer to the group representing the curve. * * \param pt The point on the curve to be randomised, given with Jacobian * coordinates. * * \param f_rng A function pointer to the random number generator. * * \param p_rng A pointer to the random number generator state. * * \return 0 if successful. */ int mbedtls_internal_ecp_randomize_jac(const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); #endif #if defined(MBEDTLS_ECP_ADD_MIXED_ALT) /** * \brief Addition: R = P + Q, mixed affine-Jacobian coordinates. * * The coordinates of Q must be normalized (= affine), * but those of P don't need to. R is not normalized. * * This function is used only as a subrutine of * ecp_mul_comb(). * * Special cases: (1) P or Q is zero, (2) R is zero, * (3) P == Q. * None of these cases can happen as intermediate step in * ecp_mul_comb(): * - at each step, P, Q and R are multiples of the base * point, the factor being less than its order, so none of * them is zero; * - Q is an odd multiple of the base point, P an even * multiple, due to the choice of precomputed points in the * modified comb method. * So branches for these cases do not leak secret information. * * We accept Q->Z being unset (saving memory in tables) as * meaning 1. * * Cost in field operations if done by [5] 3.22: * 1A := 8M + 3S * * \param grp Pointer to the group representing the curve. * * \param R Pointer to a point structure to hold the result. * * \param P Pointer to the first summand, given with Jacobian * coordinates * * \param Q Pointer to the second summand, given with affine * coordinates. * * \return 0 if successful. */ int mbedtls_internal_ecp_add_mixed(const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q); #endif /** * \brief Point doubling R = 2 P, Jacobian coordinates. * * Cost: 1D := 3M + 4S (A == 0) * 4M + 4S (A == -3) * 3M + 6S + 1a otherwise * when the implementation is based on the "dbl-1998-cmo-2" * doubling formulas in [8] and standard optimizations are * applied when curve parameter A is one of { 0, -3 }. * * \param grp Pointer to the group representing the curve. * * \param R Pointer to a point structure to hold the result. * * \param P Pointer to the point that has to be doubled, given with * Jacobian coordinates. * * \return 0 if successful. */ #if defined(MBEDTLS_ECP_DOUBLE_JAC_ALT) int mbedtls_internal_ecp_double_jac(const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_ecp_point *P); #endif /** * \brief Normalize jacobian coordinates of an array of (pointers to) * points. * * Using Montgomery's trick to perform only one inversion mod P * the cost is: * 1N(t) := 1I + (6t - 3)M + 1S * (See for example Algorithm 10.3.4. in [9]) * * This function is used only as a subrutine of * ecp_mul_comb(). * * Warning: fails (returning an error) if one of the points is * zero! * This should never happen, see choice of w in ecp_mul_comb(). * * \param grp Pointer to the group representing the curve. * * \param T Array of pointers to the points to normalise. * * \param t_len Number of elements in the array. * * \return 0 if successful, * an error if one of the points is zero. */ #if defined(MBEDTLS_ECP_NORMALIZE_JAC_MANY_ALT) int mbedtls_internal_ecp_normalize_jac_many(const mbedtls_ecp_group *grp, mbedtls_ecp_point *T[], size_t t_len); #endif /** * \brief Normalize jacobian coordinates so that Z == 0 || Z == 1. * * Cost in field operations if done by [5] 3.2.1: * 1N := 1I + 3M + 1S * * \param grp Pointer to the group representing the curve. * * \param pt pointer to the point to be normalised. This is an * input/output parameter. * * \return 0 if successful. */ #if defined(MBEDTLS_ECP_NORMALIZE_JAC_ALT) int mbedtls_internal_ecp_normalize_jac(const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt); #endif #endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ #if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED) #if defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT) int mbedtls_internal_ecp_double_add_mxz(const mbedtls_ecp_group *grp, mbedtls_ecp_point *R, mbedtls_ecp_point *S, const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q, const mbedtls_mpi *d); #endif /** * \brief Randomize projective x/z coordinates: * (X, Z) -> (l X, l Z) for random l * * \param grp pointer to the group representing the curve * * \param P the point on the curve to be randomised given with * projective coordinates. This is an input/output parameter. * * \param f_rng a function pointer to the random number generator * * \param p_rng a pointer to the random number generator state * * \return 0 if successful */ #if defined(MBEDTLS_ECP_RANDOMIZE_MXZ_ALT) int mbedtls_internal_ecp_randomize_mxz(const mbedtls_ecp_group *grp, mbedtls_ecp_point *P, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); #endif /** * \brief Normalize Montgomery x/z coordinates: X = X/Z, Z = 1. * * \param grp pointer to the group representing the curve * * \param P pointer to the point to be normalised. This is an * input/output parameter. * * \return 0 if successful */ #if defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT) int mbedtls_internal_ecp_normalize_mxz(const mbedtls_ecp_group *grp, mbedtls_ecp_point *P); #endif #endif /* MBEDTLS_ECP_MONTGOMERY_ENABLED */ #endif /* MBEDTLS_ECP_INTERNAL_ALT */ #endif /* ecp_internal.h */