/** * \file ecp.h * * \brief This file provides an API for Elliptic Curves over GF(P) (ECP). * * The use of ECP in cryptography and TLS is defined in * <em>Standards for Efficient Cryptography Group (SECG): SEC1 * Elliptic Curve Cryptography</em> and * <em>RFC-4492: Elliptic Curve Cryptography (ECC) Cipher Suites * for Transport Layer Security (TLS)</em>. * * <em>RFC-2409: The Internet Key Exchange (IKE)</em> defines ECP * group types. * */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef MBEDTLS_ECP_H #define MBEDTLS_ECP_H #include "mbedtls/private_access.h" #include "mbedtls/build_info.h" #include "mbedtls/platform_util.h" #include "mbedtls/bignum.h" /* * ECP error codes */ /** Bad input parameters to function. */ #define MBEDTLS_ERR_ECP_BAD_INPUT_DATA … /** The buffer is too small to write to. */ #define MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL … /** The requested feature is not available, for example, the requested curve is not supported. */ #define MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE … /** The signature is not valid. */ #define MBEDTLS_ERR_ECP_VERIFY_FAILED … /** Memory allocation failed. */ #define MBEDTLS_ERR_ECP_ALLOC_FAILED … /** Generation of random value, such as ephemeral key, failed. */ #define MBEDTLS_ERR_ECP_RANDOM_FAILED … /** Invalid private or public key. */ #define MBEDTLS_ERR_ECP_INVALID_KEY … /** The buffer contains a valid signature followed by more data. */ #define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH … /** Operation in progress, call again with the same parameters to continue. */ #define MBEDTLS_ERR_ECP_IN_PROGRESS … /* Flags indicating whether to include code that is specific to certain * types of curves. These flags are for internal library use only. */ #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) || \ defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) #define MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED #endif #if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \ defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) #define MBEDTLS_ECP_MONTGOMERY_ENABLED #endif #ifdef __cplusplus extern "C" { #endif /** * Domain-parameter identifiers: curve, subgroup, and generator. * * \note Only curves over prime fields are supported. * * \warning This library does not support validation of arbitrary domain * parameters. Therefore, only standardized domain parameters from trusted * sources should be used. See mbedtls_ecp_group_load(). */ /* Note: when adding a new curve: * - Add it at the end of this enum, otherwise you'll break the ABI by * changing the numerical value for existing curves. * - Increment MBEDTLS_ECP_DP_MAX below if needed. * - Update the calculation of MBEDTLS_ECP_MAX_BITS below. * - Add the corresponding MBEDTLS_ECP_DP_xxx_ENABLED macro definition to * mbedtls_config.h. * - List the curve as a dependency of MBEDTLS_ECP_C and * MBEDTLS_ECDSA_C if supported in check_config.h. * - Add the curve to the appropriate curve type macro * MBEDTLS_ECP_yyy_ENABLED above. * - Add the necessary definitions to ecp_curves.c. * - Add the curve to the ecp_supported_curves array in ecp.c. * - Add the curve to applicable profiles in x509_crt.c. * - Add the curve to applicable presets in ssl_tls.c. */ mbedtls_ecp_group_id; /** * The number of supported curves, plus one for #MBEDTLS_ECP_DP_NONE. */ #define MBEDTLS_ECP_DP_MAX … /* * Curve types */ mbedtls_ecp_curve_type; /** * Curve information, for use by other modules. * * The fields of this structure are part of the public API and can be * accessed directly by applications. Future versions of the library may * add extra fields or reorder existing fields. */ mbedtls_ecp_curve_info; /** * \brief The ECP point structure, in Jacobian coordinates. * * \note All functions expect and return points satisfying * the following condition: <code>Z == 0</code> or * <code>Z == 1</code>. Other values of \p Z are * used only by internal functions. * The point is zero, or "at infinity", if <code>Z == 0</code>. * Otherwise, \p X and \p Y are its standard (affine) * coordinates. */ mbedtls_ecp_point; #if !defined(MBEDTLS_ECP_ALT) /* * default Mbed TLS elliptic curve arithmetic implementation * * (in case MBEDTLS_ECP_ALT is defined then the developer has to provide an * alternative implementation for the whole module and it will replace this * one.) */ /** * \brief The ECP group structure. * * We consider two types of curve equations: * <ul><li>Short Weierstrass: <code>y^2 = x^3 + A x + B mod P</code> * (SEC1 + RFC-4492)</li> * <li>Montgomery: <code>y^2 = x^3 + A x^2 + x mod P</code> (Curve25519, * Curve448)</li></ul> * In both cases, the generator (\p G) for a prime-order subgroup is fixed. * * For Short Weierstrass, this subgroup is the whole curve, and its * cardinality is denoted by \p N. Our code requires that \p N is an * odd prime as mbedtls_ecp_mul() requires an odd number, and * mbedtls_ecdsa_sign() requires that it is prime for blinding purposes. * * The default implementation only initializes \p A without setting it to the * authentic value for curves with <code>A = -3</code>(SECP256R1, etc), in which * case you need to load \p A by yourself when using domain parameters directly, * for example: * \code * mbedtls_mpi_init(&A); * mbedtls_ecp_group_init(&grp); * CHECK_RETURN(mbedtls_ecp_group_load(&grp, grp_id)); * if (mbedtls_ecp_group_a_is_minus_3(&grp)) { * CHECK_RETURN(mbedtls_mpi_sub_int(&A, &grp.P, 3)); * } else { * CHECK_RETURN(mbedtls_mpi_copy(&A, &grp.A)); * } * * do_something_with_a(&A); * * cleanup: * mbedtls_mpi_free(&A); * mbedtls_ecp_group_free(&grp); * \endcode * * For Montgomery curves, we do not store \p A, but <code>(A + 2) / 4</code>, * which is the quantity used in the formulas. Additionally, \p nbits is * not the size of \p N but the required size for private keys. * * If \p modp is NULL, reduction modulo \p P is done using a generic algorithm. * Otherwise, \p modp must point to a function that takes an \p mbedtls_mpi in the * range of <code>0..2^(2*pbits)-1</code>, and transforms it in-place to an integer * which is congruent mod \p P to the given MPI, and is close enough to \p pbits * in size, so that it may be efficiently brought in the 0..P-1 range by a few * additions or subtractions. Therefore, it is only an approximate modular * reduction. It must return 0 on success and non-zero on failure. * * \note Alternative implementations of the ECP module must obey the * following constraints. * * Group IDs must be distinct: if two group structures have * the same ID, then they must be identical. * * The fields \c id, \c P, \c A, \c B, \c G, \c N, * \c pbits and \c nbits must have the same type and semantics * as in the built-in implementation. * They must be available for reading, but direct modification * of these fields does not need to be supported. * They do not need to be at the same offset in the structure. */ mbedtls_ecp_group; /** * \name SECTION: Module settings * * The configuration options you can set for this module are in this section. * Either change them in mbedtls_config.h, or define them using the compiler command line. * \{ */ #if !defined(MBEDTLS_ECP_WINDOW_SIZE) /* * Maximum "window" size used for point multiplication. * Default: a point where higher memory usage yields diminishing performance * returns. * Minimum value: 2. Maximum value: 7. * * Result is an array of at most ( 1 << ( MBEDTLS_ECP_WINDOW_SIZE - 1 ) ) * points used for point multiplication. This value is directly tied to EC * peak memory usage, so decreasing it by one should roughly cut memory usage * by two (if large curves are in use). * * Reduction in size may reduce speed, but larger curves are impacted first. * Sample performances (in ECDHE handshakes/s, with FIXED_POINT_OPTIM = 1): * w-size: 6 5 4 3 2 * 521 145 141 135 120 97 * 384 214 209 198 177 146 * 256 320 320 303 262 226 * 224 475 475 453 398 342 * 192 640 640 633 587 476 */ #define MBEDTLS_ECP_WINDOW_SIZE … #endif /* MBEDTLS_ECP_WINDOW_SIZE */ #if !defined(MBEDTLS_ECP_FIXED_POINT_OPTIM) /* * Trade code size for speed on fixed-point multiplication. * * This speeds up repeated multiplication of the generator (that is, the * multiplication in ECDSA signatures, and half of the multiplications in * ECDSA verification and ECDHE) by a factor roughly 3 to 4. * * For each n-bit Short Weierstrass curve that is enabled, this adds 4n bytes * of code size if n < 384 and 8n otherwise. * * Change this value to 0 to reduce code size. */ #define MBEDTLS_ECP_FIXED_POINT_OPTIM … #endif /* MBEDTLS_ECP_FIXED_POINT_OPTIM */ /** \} name SECTION: Module settings */ #else /* MBEDTLS_ECP_ALT */ #include "ecp_alt.h" #endif /* MBEDTLS_ECP_ALT */ /** * The maximum size of the groups, that is, of \c N and \c P. */ #if !defined(MBEDTLS_ECP_LIGHT) /* Dummy definition to help code that has optional ECP support and * defines an MBEDTLS_ECP_MAX_BYTES-sized array unconditionally. */ #define MBEDTLS_ECP_MAX_BITS … /* Note: the curves must be listed in DECREASING size! */ #elif defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #elif defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) #define MBEDTLS_ECP_MAX_BITS … #else /* !MBEDTLS_ECP_LIGHT */ #error "Missing definition of MBEDTLS_ECP_MAX_BITS" #endif /* !MBEDTLS_ECP_LIGHT */ #define MBEDTLS_ECP_MAX_BYTES … #define MBEDTLS_ECP_MAX_PT_LEN … #if defined(MBEDTLS_ECP_RESTARTABLE) /** * \brief Internal restart context for multiplication * * \note Opaque struct */ typedef struct mbedtls_ecp_restart_mul mbedtls_ecp_restart_mul_ctx; /** * \brief Internal restart context for ecp_muladd() * * \note Opaque struct */ typedef struct mbedtls_ecp_restart_muladd mbedtls_ecp_restart_muladd_ctx; /** * \brief General context for resuming ECC operations */ typedef struct { unsigned MBEDTLS_PRIVATE(ops_done); /*!< current ops count */ unsigned MBEDTLS_PRIVATE(depth); /*!< call depth (0 = top-level) */ mbedtls_ecp_restart_mul_ctx *MBEDTLS_PRIVATE(rsm); /*!< ecp_mul_comb() sub-context */ mbedtls_ecp_restart_muladd_ctx *MBEDTLS_PRIVATE(ma); /*!< ecp_muladd() sub-context */ } mbedtls_ecp_restart_ctx; /* * Operation counts for restartable functions */ #define MBEDTLS_ECP_OPS_CHK … #define MBEDTLS_ECP_OPS_DBL … #define MBEDTLS_ECP_OPS_ADD … #define MBEDTLS_ECP_OPS_INV … /** * \brief Internal; for restartable functions in other modules. * Check and update basic ops budget. * * \param grp Group structure * \param rs_ctx Restart context * \param ops Number of basic ops to do * * \return \c 0 if doing \p ops basic ops is still allowed, * \return #MBEDTLS_ERR_ECP_IN_PROGRESS otherwise. */ int mbedtls_ecp_check_budget(const mbedtls_ecp_group *grp, mbedtls_ecp_restart_ctx *rs_ctx, unsigned ops); /* Utility macro for checking and updating ops budget */ #define MBEDTLS_ECP_BUDGET … #else /* MBEDTLS_ECP_RESTARTABLE */ #define MBEDTLS_ECP_BUDGET(ops) … /* We want to declare restartable versions of existing functions anyway */ mbedtls_ecp_restart_ctx; #endif /* MBEDTLS_ECP_RESTARTABLE */ /** * \brief The ECP key-pair structure. * * A generic key-pair that may be used for ECDSA and fixed ECDH, for example. * * \note Members are deliberately in the same order as in the * ::mbedtls_ecdsa_context structure. */ mbedtls_ecp_keypair; /** * The uncompressed point format for Short Weierstrass curves * (MBEDTLS_ECP_DP_SECP_XXX and MBEDTLS_ECP_DP_BP_XXX). */ #define MBEDTLS_ECP_PF_UNCOMPRESSED … /** * The compressed point format for Short Weierstrass curves * (MBEDTLS_ECP_DP_SECP_XXX and MBEDTLS_ECP_DP_BP_XXX). * * \warning While this format is supported for all concerned curves for * writing, when it comes to parsing, it is not supported for all * curves. Specifically, parsing compressed points on * MBEDTLS_ECP_DP_SECP224R1 and MBEDTLS_ECP_DP_SECP224K1 is not * supported. */ #define MBEDTLS_ECP_PF_COMPRESSED … /* * Some other constants from RFC 4492 */ #define MBEDTLS_ECP_TLS_NAMED_CURVE … #if defined(MBEDTLS_ECP_RESTARTABLE) /** * \brief Set the maximum number of basic operations done in a row. * * If more operations are needed to complete a computation, * #MBEDTLS_ERR_ECP_IN_PROGRESS will be returned by the * function performing the computation. It is then the * caller's responsibility to either call again with the same * parameters until it returns 0 or an error code; or to free * the restart context if the operation is to be aborted. * * It is strictly required that all input parameters and the * restart context be the same on successive calls for the * same operation, but output parameters need not be the * same; they must not be used until the function finally * returns 0. * * This only applies to functions whose documentation * mentions they may return #MBEDTLS_ERR_ECP_IN_PROGRESS (or * #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS for functions in the * SSL module). For functions that accept a "restart context" * argument, passing NULL disables restart and makes the * function equivalent to the function with the same name * with \c _restartable removed. For functions in the ECDH * module, restart is disabled unless the function accepts * an "ECDH context" argument and * mbedtls_ecdh_enable_restart() was previously called on * that context. For function in the SSL module, restart is * only enabled for specific sides and key exchanges * (currently only for clients and ECDHE-ECDSA). * * \warning Using the PSA interruptible interfaces with keys in local * storage and no accelerator driver will also call this * function to set the values specified via those interfaces, * overwriting values previously set. Care should be taken if * mixing these two interfaces. * * \param max_ops Maximum number of basic operations done in a row. * Default: 0 (unlimited). * Lower (non-zero) values mean ECC functions will block for * a lesser maximum amount of time. * * \note A "basic operation" is defined as a rough equivalent of a * multiplication in GF(p) for the NIST P-256 curve. * As an indication, with default settings, a scalar * multiplication (full run of \c mbedtls_ecp_mul()) is: * - about 3300 basic operations for P-256 * - about 9400 basic operations for P-384 * * \note Very low values are not always respected: sometimes * functions need to block for a minimum number of * operations, and will do so even if max_ops is set to a * lower value. That minimum depends on the curve size, and * can be made lower by decreasing the value of * \c MBEDTLS_ECP_WINDOW_SIZE. As an indication, here is the * lowest effective value for various curves and values of * that parameter (w for short): * w=6 w=5 w=4 w=3 w=2 * P-256 208 208 160 136 124 * P-384 682 416 320 272 248 * P-521 1364 832 640 544 496 * * \note This setting is currently ignored by Curve25519. */ void mbedtls_ecp_set_max_ops(unsigned max_ops); /** * \brief Check if restart is enabled (max_ops != 0) * * \return \c 0 if \c max_ops == 0 (restart disabled) * \return \c 1 otherwise (restart enabled) */ int mbedtls_ecp_restart_is_enabled(void); #endif /* MBEDTLS_ECP_RESTARTABLE */ /* * Get the type of a curve */ mbedtls_ecp_curve_type mbedtls_ecp_get_type(const mbedtls_ecp_group *grp); /** * \brief This function retrieves the information defined in * mbedtls_ecp_curve_info() for all supported curves. * * \note This function returns information about all curves * supported by the library. Some curves may not be * supported for all algorithms. Call mbedtls_ecdh_can_do() * or mbedtls_ecdsa_can_do() to check if a curve is * supported for ECDH or ECDSA. * * \return A statically allocated array. The last entry is 0. */ const mbedtls_ecp_curve_info *mbedtls_ecp_curve_list(void); /** * \brief This function retrieves the list of internal group * identifiers of all supported curves in the order of * preference. * * \note This function returns information about all curves * supported by the library. Some curves may not be * supported for all algorithms. Call mbedtls_ecdh_can_do() * or mbedtls_ecdsa_can_do() to check if a curve is * supported for ECDH or ECDSA. * * \return A statically allocated array, * terminated with MBEDTLS_ECP_DP_NONE. */ const mbedtls_ecp_group_id *mbedtls_ecp_grp_id_list(void); /** * \brief This function retrieves curve information from an internal * group identifier. * * \param grp_id An \c MBEDTLS_ECP_DP_XXX value. * * \return The associated curve information on success. * \return NULL on failure. */ const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_grp_id(mbedtls_ecp_group_id grp_id); /** * \brief This function retrieves curve information from a TLS * NamedCurve value. * * \param tls_id An \c MBEDTLS_ECP_DP_XXX value. * * \return The associated curve information on success. * \return NULL on failure. */ const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_tls_id(uint16_t tls_id); /** * \brief This function retrieves curve information from a * human-readable name. * * \param name The human-readable name. * * \return The associated curve information on success. * \return NULL on failure. */ const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_name(const char *name); /** * \brief This function initializes a point as zero. * * \param pt The point to initialize. */ void mbedtls_ecp_point_init(mbedtls_ecp_point *pt); /** * \brief This function initializes an ECP group context * without loading any domain parameters. * * \note After this function is called, domain parameters * for various ECP groups can be loaded through the * mbedtls_ecp_group_load() or mbedtls_ecp_tls_read_group() * functions. */ void mbedtls_ecp_group_init(mbedtls_ecp_group *grp); /** * \brief This function initializes a key pair as an invalid one. * * \param key The key pair to initialize. */ void mbedtls_ecp_keypair_init(mbedtls_ecp_keypair *key); /** * \brief This function frees the components of a point. * * \param pt The point to free. */ void mbedtls_ecp_point_free(mbedtls_ecp_point *pt); /** * \brief This function frees the components of an ECP group. * * \param grp The group to free. This may be \c NULL, in which * case this function returns immediately. If it is not * \c NULL, it must point to an initialized ECP group. */ void mbedtls_ecp_group_free(mbedtls_ecp_group *grp); /** * \brief This function frees the components of a key pair. * * \param key The key pair to free. This may be \c NULL, in which * case this function returns immediately. If it is not * \c NULL, it must point to an initialized ECP key pair. */ void mbedtls_ecp_keypair_free(mbedtls_ecp_keypair *key); #if defined(MBEDTLS_ECP_RESTARTABLE) /** * \brief Initialize a restart context. * * \param ctx The restart context to initialize. This must * not be \c NULL. */ void mbedtls_ecp_restart_init(mbedtls_ecp_restart_ctx *ctx); /** * \brief Free the components of a restart context. * * \param ctx The restart context to free. This may be \c NULL, in which * case this function returns immediately. If it is not * \c NULL, it must point to an initialized restart context. */ void mbedtls_ecp_restart_free(mbedtls_ecp_restart_ctx *ctx); #endif /* MBEDTLS_ECP_RESTARTABLE */ /** * \brief This function copies the contents of point \p Q into * point \p P. * * \param P The destination point. This must be initialized. * \param Q The source point. This must be initialized. * * \return \c 0 on success. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return Another negative error code for other kinds of failure. */ int mbedtls_ecp_copy(mbedtls_ecp_point *P, const mbedtls_ecp_point *Q); /** * \brief This function copies the contents of group \p src into * group \p dst. * * \param dst The destination group. This must be initialized. * \param src The source group. This must be initialized. * * \return \c 0 on success. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_group_copy(mbedtls_ecp_group *dst, const mbedtls_ecp_group *src); /** * \brief This function sets a point to the point at infinity. * * \param pt The point to set. This must be initialized. * * \return \c 0 on success. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_set_zero(mbedtls_ecp_point *pt); /** * \brief This function checks if a point is the point at infinity. * * \param pt The point to test. This must be initialized. * * \return \c 1 if the point is zero. * \return \c 0 if the point is non-zero. * \return A negative error code on failure. */ int mbedtls_ecp_is_zero(mbedtls_ecp_point *pt); /** * \brief This function compares two points. * * \note This assumes that the points are normalized. Otherwise, * they may compare as "not equal" even if they are. * * \param P The first point to compare. This must be initialized. * \param Q The second point to compare. This must be initialized. * * \return \c 0 if the points are equal. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the points are not equal. */ int mbedtls_ecp_point_cmp(const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q); /** * \brief This function imports a non-zero point from two ASCII * strings. * * \param P The destination point. This must be initialized. * \param radix The numeric base of the input. * \param x The first affine coordinate, as a null-terminated string. * \param y The second affine coordinate, as a null-terminated string. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_MPI_XXX error code on failure. */ int mbedtls_ecp_point_read_string(mbedtls_ecp_point *P, int radix, const char *x, const char *y); /** * \brief This function exports a point into unsigned binary data. * * \param grp The group to which the point should belong. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param P The point to export. This must be initialized. * \param format The point format. This must be either * #MBEDTLS_ECP_PF_COMPRESSED or #MBEDTLS_ECP_PF_UNCOMPRESSED. * (For groups without these formats, this parameter is * ignored. But it still has to be either of the above * values.) * \param olen The address at which to store the length of * the output in Bytes. This must not be \c NULL. * \param buf The output buffer. This must be a writable buffer * of length \p buflen Bytes. * \param buflen The length of the output buffer \p buf in Bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the output buffer * is too small to hold the point. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the point format * or the export for the given group is not implemented. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_point_write_binary(const mbedtls_ecp_group *grp, const mbedtls_ecp_point *P, int format, size_t *olen, unsigned char *buf, size_t buflen); /** * \brief This function imports a point from unsigned binary data. * * \note This function does not check that the point actually * belongs to the given group, see mbedtls_ecp_check_pubkey() * for that. * * \note For compressed points, see #MBEDTLS_ECP_PF_COMPRESSED for * limitations. * * \param grp The group to which the point should belong. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param P The destination context to import the point to. * This must be initialized. * \param buf The input buffer. This must be a readable buffer * of length \p ilen Bytes. * \param ilen The length of the input buffer \p buf in Bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the input is invalid. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the import for the * given group is not implemented. */ int mbedtls_ecp_point_read_binary(const mbedtls_ecp_group *grp, mbedtls_ecp_point *P, const unsigned char *buf, size_t ilen); /** * \brief This function imports a point from a TLS ECPoint record. * * \note On function return, \p *buf is updated to point immediately * after the ECPoint record. * * \param grp The ECP group to use. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param pt The destination point. * \param buf The address of the pointer to the start of the input buffer. * \param len The length of the buffer. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_MPI_XXX error code on initialization * failure. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid. */ int mbedtls_ecp_tls_read_point(const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt, const unsigned char **buf, size_t len); /** * \brief This function exports a point as a TLS ECPoint record * defined in RFC 4492, Section 5.4. * * \param grp The ECP group to use. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param pt The point to be exported. This must be initialized. * \param format The point format to use. This must be either * #MBEDTLS_ECP_PF_COMPRESSED or #MBEDTLS_ECP_PF_UNCOMPRESSED. * \param olen The address at which to store the length in Bytes * of the data written. * \param buf The target buffer. This must be a writable buffer of * length \p blen Bytes. * \param blen The length of the target buffer \p buf in Bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the input is invalid. * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the target buffer * is too small to hold the exported point. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_tls_write_point(const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt, int format, size_t *olen, unsigned char *buf, size_t blen); /** * \brief This function sets up an ECP group context * from a standardized set of domain parameters. * * \note The index should be a value of the NamedCurve enum, * as defined in <em>RFC-4492: Elliptic Curve Cryptography * (ECC) Cipher Suites for Transport Layer Security (TLS)</em>, * usually in the form of an \c MBEDTLS_ECP_DP_XXX macro. * * \param grp The group context to setup. This must be initialized. * \param id The identifier of the domain parameter set to load. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if \p id doesn't * correspond to a known group. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_group_load(mbedtls_ecp_group *grp, mbedtls_ecp_group_id id); /** * \brief This function sets up an ECP group context from a TLS * ECParameters record as defined in RFC 4492, Section 5.4. * * \note The read pointer \p buf is updated to point right after * the ECParameters record on exit. * * \param grp The group context to setup. This must be initialized. * \param buf The address of the pointer to the start of the input buffer. * \param len The length of the input buffer \c *buf in Bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the group is not * recognized. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_tls_read_group(mbedtls_ecp_group *grp, const unsigned char **buf, size_t len); /** * \brief This function extracts an elliptic curve group ID from a * TLS ECParameters record as defined in RFC 4492, Section 5.4. * * \note The read pointer \p buf is updated to point right after * the ECParameters record on exit. * * \param grp The address at which to store the group id. * This must not be \c NULL. * \param buf The address of the pointer to the start of the input buffer. * \param len The length of the input buffer \c *buf in Bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the group is not * recognized. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_tls_read_group_id(mbedtls_ecp_group_id *grp, const unsigned char **buf, size_t len); /** * \brief This function exports an elliptic curve as a TLS * ECParameters record as defined in RFC 4492, Section 5.4. * * \param grp The ECP group to be exported. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param olen The address at which to store the number of Bytes written. * This must not be \c NULL. * \param buf The buffer to write to. This must be a writable buffer * of length \p blen Bytes. * \param blen The length of the output buffer \p buf in Bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the output * buffer is too small to hold the exported group. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_tls_write_group(const mbedtls_ecp_group *grp, size_t *olen, unsigned char *buf, size_t blen); /** * \brief This function performs a scalar multiplication of a point * by an integer: \p R = \p m * \p P. * * It is not thread-safe to use same group in multiple threads. * * \note To prevent timing attacks, this function * executes the exact same sequence of base-field * operations for any valid \p m. It avoids any if-branch or * array index depending on the value of \p m. It also uses * \p f_rng to randomize some intermediate results. * * \param grp The ECP group to use. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param R The point in which to store the result of the calculation. * This must be initialized. * \param m The integer by which to multiply. This must be initialized. * \param P The point to multiply. This must be initialized. * \param f_rng The RNG function. This must not be \c NULL. * \param p_rng The RNG context to be passed to \p f_rng. This may be \c * NULL if \p f_rng doesn't need a context. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m is not a valid private * key, or \p P is not a valid public key. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_mul(mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_mpi *m, const mbedtls_ecp_point *P, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief This function performs multiplication of a point by * an integer: \p R = \p m * \p P in a restartable way. * * \see mbedtls_ecp_mul() * * \note This function does the same as \c mbedtls_ecp_mul(), but * it can return early and restart according to the limit set * with \c mbedtls_ecp_set_max_ops() to reduce blocking. * * \param grp The ECP group to use. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param R The point in which to store the result of the calculation. * This must be initialized. * \param m The integer by which to multiply. This must be initialized. * \param P The point to multiply. This must be initialized. * \param f_rng The RNG function. This must not be \c NULL. * \param p_rng The RNG context to be passed to \p f_rng. This may be \c * NULL if \p f_rng doesn't need a context. * \param rs_ctx The restart context (NULL disables restart). * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m is not a valid private * key, or \p P is not a valid public key. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of * operations was reached: see \c mbedtls_ecp_set_max_ops(). * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_mul_restartable(mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_mpi *m, const mbedtls_ecp_point *P, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, mbedtls_ecp_restart_ctx *rs_ctx); #if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) /** * \brief This function checks if domain parameter A of the curve is * \c -3. * * \note This function is only defined for short Weierstrass curves. * It may not be included in builds without any short * Weierstrass curve. * * \param grp The ECP group to use. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * * \return \c 1 if <code>A = -3</code>. * \return \c 0 Otherwise. */ static inline int mbedtls_ecp_group_a_is_minus_3(const mbedtls_ecp_group *grp) { … } /** * \brief This function performs multiplication and addition of two * points by integers: \p R = \p m * \p P + \p n * \p Q * * It is not thread-safe to use same group in multiple threads. * * \note In contrast to mbedtls_ecp_mul(), this function does not * guarantee a constant execution flow and timing. * * \note This function is only defined for short Weierstrass curves. * It may not be included in builds without any short * Weierstrass curve. * * \param grp The ECP group to use. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param R The point in which to store the result of the calculation. * This must be initialized. * \param m The integer by which to multiply \p P. * This must be initialized. * \param P The point to multiply by \p m. This must be initialized. * \param n The integer by which to multiply \p Q. * This must be initialized. * \param Q The point to be multiplied by \p n. * This must be initialized. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m or \p n are not * valid private keys, or \p P or \p Q are not valid public * keys. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if \p grp does not * designate a short Weierstrass curve. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_muladd(mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_mpi *m, const mbedtls_ecp_point *P, const mbedtls_mpi *n, const mbedtls_ecp_point *Q); /** * \brief This function performs multiplication and addition of two * points by integers: \p R = \p m * \p P + \p n * \p Q in a * restartable way. * * \see \c mbedtls_ecp_muladd() * * \note This function works the same as \c mbedtls_ecp_muladd(), * but it can return early and restart according to the limit * set with \c mbedtls_ecp_set_max_ops() to reduce blocking. * * \note This function is only defined for short Weierstrass curves. * It may not be included in builds without any short * Weierstrass curve. * * \param grp The ECP group to use. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param R The point in which to store the result of the calculation. * This must be initialized. * \param m The integer by which to multiply \p P. * This must be initialized. * \param P The point to multiply by \p m. This must be initialized. * \param n The integer by which to multiply \p Q. * This must be initialized. * \param Q The point to be multiplied by \p n. * This must be initialized. * \param rs_ctx The restart context (NULL disables restart). * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m or \p n are not * valid private keys, or \p P or \p Q are not valid public * keys. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if \p grp does not * designate a short Weierstrass curve. * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of * operations was reached: see \c mbedtls_ecp_set_max_ops(). * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_muladd_restartable( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, const mbedtls_mpi *m, const mbedtls_ecp_point *P, const mbedtls_mpi *n, const mbedtls_ecp_point *Q, mbedtls_ecp_restart_ctx *rs_ctx); #endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ /** * \brief This function checks that a point is a valid public key * on this curve. * * It only checks that the point is non-zero, has * valid coordinates and lies on the curve. It does not verify * that it is indeed a multiple of \c G. This additional * check is computationally more expensive, is not required * by standards, and should not be necessary if the group * used has a small cofactor. In particular, it is useless for * the NIST groups which all have a cofactor of 1. * * \note This function uses bare components rather than an * ::mbedtls_ecp_keypair structure, to ease use with other * structures, such as ::mbedtls_ecdh_context or * ::mbedtls_ecdsa_context. * * \param grp The ECP group the point should belong to. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param pt The point to check. This must be initialized. * * \return \c 0 if the point is a valid public key. * \return #MBEDTLS_ERR_ECP_INVALID_KEY if the point is not * a valid public key for the given curve. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_check_pubkey(const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt); /** * \brief This function checks that an \c mbedtls_mpi is a * valid private key for this curve. * * \note This function uses bare components rather than an * ::mbedtls_ecp_keypair structure to ease use with other * structures, such as ::mbedtls_ecdh_context or * ::mbedtls_ecdsa_context. * * \param grp The ECP group the private key should belong to. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param d The integer to check. This must be initialized. * * \return \c 0 if the point is a valid private key. * \return #MBEDTLS_ERR_ECP_INVALID_KEY if the point is not a valid * private key for the given curve. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_check_privkey(const mbedtls_ecp_group *grp, const mbedtls_mpi *d); /** * \brief This function generates a private key. * * \param grp The ECP group to generate a private key for. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param d The destination MPI (secret part). This must be initialized. * \param f_rng The RNG function. This must not be \c NULL. * \param p_rng The RNG parameter to be passed to \p f_rng. This may be * \c NULL if \p f_rng doesn't need a context argument. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code * on failure. */ int mbedtls_ecp_gen_privkey(const mbedtls_ecp_group *grp, mbedtls_mpi *d, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief This function generates a keypair with a configurable base * point. * * \note This function uses bare components rather than an * ::mbedtls_ecp_keypair structure to ease use with other * structures, such as ::mbedtls_ecdh_context or * ::mbedtls_ecdsa_context. * * \param grp The ECP group to generate a key pair for. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param G The base point to use. This must be initialized * and belong to \p grp. It replaces the default base * point \c grp->G used by mbedtls_ecp_gen_keypair(). * \param d The destination MPI (secret part). * This must be initialized. * \param Q The destination point (public part). * This must be initialized. * \param f_rng The RNG function. This must not be \c NULL. * \param p_rng The RNG context to be passed to \p f_rng. This may * be \c NULL if \p f_rng doesn't need a context argument. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code * on failure. */ int mbedtls_ecp_gen_keypair_base(mbedtls_ecp_group *grp, const mbedtls_ecp_point *G, mbedtls_mpi *d, mbedtls_ecp_point *Q, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief This function generates an ECP keypair. * * \note This function uses bare components rather than an * ::mbedtls_ecp_keypair structure to ease use with other * structures, such as ::mbedtls_ecdh_context or * ::mbedtls_ecdsa_context. * * \param grp The ECP group to generate a key pair for. * This must be initialized and have group parameters * set, for example through mbedtls_ecp_group_load(). * \param d The destination MPI (secret part). * This must be initialized. * \param Q The destination point (public part). * This must be initialized. * \param f_rng The RNG function. This must not be \c NULL. * \param p_rng The RNG context to be passed to \p f_rng. This may * be \c NULL if \p f_rng doesn't need a context argument. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code * on failure. */ int mbedtls_ecp_gen_keypair(mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief This function generates an ECP key. * * \param grp_id The ECP group identifier. * \param key The destination key. This must be initialized. * \param f_rng The RNG function to use. This must not be \c NULL. * \param p_rng The RNG context to be passed to \p f_rng. This may * be \c NULL if \p f_rng doesn't need a context argument. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code * on failure. */ int mbedtls_ecp_gen_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** \brief Set the public key in a key pair object. * * \note This function does not check that the point actually * belongs to the given group. Call mbedtls_ecp_check_pubkey() * on \p Q before calling this function to check that. * * \note This function does not check that the public key matches * the private key that is already in \p key, if any. * To check the consistency of the resulting key pair object, * call mbedtls_ecp_check_pub_priv() after setting both * the public key and the private key. * * \param grp_id The ECP group identifier. * \param key The key pair object. It must be initialized. * If its group has already been set, it must match \p grp_id. * If its group has not been set, it will be set to \p grp_id. * If the public key has already been set, it is overwritten. * \param Q The public key to copy. This must be a point on the * curve indicated by \p grp_id. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if \p key does not * match \p grp_id. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the operation for * the group is not implemented. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_set_public_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key, const mbedtls_ecp_point *Q); /** * \brief This function reads an elliptic curve private key. * * \note This function does not set the public key in the * key pair object. Without a public key, the key pair object * cannot be used with operations that require the public key. * Call mbedtls_ecp_keypair_calc_public() to set the public * key from the private key. Alternatively, you can call * mbedtls_ecp_set_public_key() to set the public key part, * and then optionally mbedtls_ecp_check_pub_priv() to check * that the private and public parts are consistent. * * \note If a public key has already been set in the key pair * object, this function does not check that it is consistent * with the private key. Call mbedtls_ecp_check_pub_priv() * after setting both the public key and the private key * to make that check. * * \param grp_id The ECP group identifier. * \param key The destination key. * \param buf The buffer containing the binary representation of the * key. (Big endian integer for Weierstrass curves, byte * string for Montgomery curves.) * \param buflen The length of the buffer in bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_INVALID_KEY error if the key is * invalid. * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the operation for * the group is not implemented. * \return Another negative error code on different kinds of failure. */ int mbedtls_ecp_read_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key, const unsigned char *buf, size_t buflen); #if !defined(MBEDTLS_DEPRECATED_REMOVED) /** * \brief This function exports an elliptic curve private key. * * \deprecated Note that although this function accepts an output * buffer that is smaller or larger than the key, most key * import interfaces require the output to have exactly * key's nominal length. It is generally simplest to * pass the key's nominal length as \c buflen, after * checking that the output buffer is large enough. * See the description of the \p buflen parameter for * how to calculate the nominal length. * To avoid this difficulty, use mbedtls_ecp_write_key_ext() * instead. * mbedtls_ecp_write_key() is deprecated and will be * removed in a future version of the library. * * \note If the private key was not set in \p key, * the output is unspecified. Future versions * may return an error in that case. * * \param key The private key. * \param buf The output buffer for containing the binary representation * of the key. * For Weierstrass curves, this is the big-endian * representation, padded with null bytes at the beginning * to reach \p buflen bytes. * For Montgomery curves, this is the standard byte string * representation (which is little-endian), padded with * null bytes at the end to reach \p buflen bytes. * \param buflen The total length of the buffer in bytes. * The length of the output is * (`grp->nbits` + 7) / 8 bytes * where `grp->nbits` is the private key size in bits. * For Weierstrass keys, if the output buffer is smaller, * leading zeros are trimmed to fit if possible. For * Montgomery keys, the output buffer must always be large * enough for the nominal length. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL or * #MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if the \p key * representation is larger than the available space in \p buf. * \return Another negative error code on different kinds of failure. */ int MBEDTLS_DEPRECATED mbedtls_ecp_write_key(mbedtls_ecp_keypair *key, unsigned char *buf, size_t buflen); #endif /* MBEDTLS_DEPRECATED_REMOVED */ /** * \brief This function exports an elliptic curve private key. * * \param key The private key. * \param olen On success, the length of the private key. * This is always (`grp->nbits` + 7) / 8 bytes * where `grp->nbits` is the private key size in bits. * \param buf The output buffer for containing the binary representation * of the key. * \param buflen The total length of the buffer in bytes. * #MBEDTLS_ECP_MAX_BYTES is always sufficient. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the \p key * representation is larger than the available space in \p buf. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if no private key is * set in \p key. * \return Another negative error code on different kinds of failure. */ int mbedtls_ecp_write_key_ext(const mbedtls_ecp_keypair *key, size_t *olen, unsigned char *buf, size_t buflen); /** * \brief This function exports an elliptic curve public key. * * \note If the public key was not set in \p key, * the output is unspecified. Future versions * may return an error in that case. * * \param key The public key. * \param format The point format. This must be either * #MBEDTLS_ECP_PF_COMPRESSED or #MBEDTLS_ECP_PF_UNCOMPRESSED. * (For groups without these formats, this parameter is * ignored. But it still has to be either of the above * values.) * \param olen The address at which to store the length of * the output in Bytes. This must not be \c NULL. * \param buf The output buffer. This must be a writable buffer * of length \p buflen Bytes. * \param buflen The length of the output buffer \p buf in Bytes. * * \return \c 0 on success. * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the output buffer * is too small to hold the point. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the point format * or the export for the given group is not implemented. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_write_public_key(const mbedtls_ecp_keypair *key, int format, size_t *olen, unsigned char *buf, size_t buflen); /** * \brief This function checks that the keypair objects * \p pub and \p prv have the same group and the * same public point, and that the private key in * \p prv is consistent with the public key. * * \param pub The keypair structure holding the public key. This * must be initialized. If it contains a private key, that * part is ignored. * \param prv The keypair structure holding the full keypair. * This must be initialized. * \param f_rng The RNG function. This must not be \c NULL. * \param p_rng The RNG context to be passed to \p f_rng. This may be \c * NULL if \p f_rng doesn't need a context. * * \return \c 0 on success, meaning that the keys are valid and match. * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the keys are invalid or do not match. * \return An \c MBEDTLS_ERR_ECP_XXX or an \c MBEDTLS_ERR_MPI_XXX * error code on calculation failure. */ int mbedtls_ecp_check_pub_priv( const mbedtls_ecp_keypair *pub, const mbedtls_ecp_keypair *prv, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** \brief Calculate the public key from a private key in a key pair. * * \param key A keypair structure. It must have a private key set. * If the public key is set, it will be overwritten. * \param f_rng The RNG function. This must not be \c NULL. * \param p_rng The RNG context to be passed to \p f_rng. This may be \c * NULL if \p f_rng doesn't need a context. * * \return \c 0 on success. The key pair object can be used for * operations that require the public key. * \return An \c MBEDTLS_ERR_ECP_XXX or an \c MBEDTLS_ERR_MPI_XXX * error code on calculation failure. */ int mbedtls_ecp_keypair_calc_public( mbedtls_ecp_keypair *key, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** \brief Query the group that a key pair belongs to. * * \param key The key pair to query. * * \return The group ID for the group registered in the key pair * object. * This is \c MBEDTLS_ECP_DP_NONE if no group has been set * in the key pair object. */ mbedtls_ecp_group_id mbedtls_ecp_keypair_get_group_id( const mbedtls_ecp_keypair *key); /** * \brief This function exports generic key-pair parameters. * * Each of the output parameters can be a null pointer * if you do not need that parameter. * * \note If the private key or the public key was not set in \p key, * the corresponding output is unspecified. Future versions * may return an error in that case. * * \param key The key pair to export from. * \param grp Slot for exported ECP group. * It must either be null or point to an initialized ECP group. * \param d Slot for the exported secret value. * It must either be null or point to an initialized mpi. * \param Q Slot for the exported public value. * It must either be null or point to an initialized ECP point. * * \return \c 0 on success, * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if key id doesn't * correspond to a known group. * \return Another negative error code on other kinds of failure. */ int mbedtls_ecp_export(const mbedtls_ecp_keypair *key, mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q); #if defined(MBEDTLS_SELF_TEST) /** * \brief The ECP checkup routine. * * \return \c 0 on success. * \return \c 1 on failure. */ int mbedtls_ecp_self_test(int verbose); #endif /* MBEDTLS_SELF_TEST */ #ifdef __cplusplus } #endif #endif /* ecp.h */
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