diff options
Diffstat (limited to 'include/mbedtls/ecp.h')
| -rw-r--r-- | include/mbedtls/ecp.h | 1362 |
1 files changed, 1362 insertions, 0 deletions
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h new file mode 100644 index 0000000..7f5e880 --- /dev/null +++ b/include/mbedtls/ecp.h @@ -0,0 +1,1362 @@ +/** + * \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/bignum.h" + +/* + * ECP error codes + */ +/** Bad input parameters to function. */ +#define MBEDTLS_ERR_ECP_BAD_INPUT_DATA -0x4F80 +/** The buffer is too small to write to. */ +#define MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL -0x4F00 +/** The requested feature is not available, for example, the requested curve is not supported. */ +#define MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE -0x4E80 +/** The signature is not valid. */ +#define MBEDTLS_ERR_ECP_VERIFY_FAILED -0x4E00 +/** Memory allocation failed. */ +#define MBEDTLS_ERR_ECP_ALLOC_FAILED -0x4D80 +/** Generation of random value, such as ephemeral key, failed. */ +#define MBEDTLS_ERR_ECP_RANDOM_FAILED -0x4D00 +/** Invalid private or public key. */ +#define MBEDTLS_ERR_ECP_INVALID_KEY -0x4C80 +/** The buffer contains a valid signature followed by more data. */ +#define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH -0x4C00 +/** Operation in progress, call again with the same parameters to continue. */ +#define MBEDTLS_ERR_ECP_IN_PROGRESS -0x4B00 + +/* 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. + */ +typedef enum { + MBEDTLS_ECP_DP_NONE = 0, /*!< Curve not defined. */ + MBEDTLS_ECP_DP_SECP192R1, /*!< Domain parameters for the 192-bit curve defined by FIPS 186-4 and SEC1. */ + MBEDTLS_ECP_DP_SECP224R1, /*!< Domain parameters for the 224-bit curve defined by FIPS 186-4 and SEC1. */ + MBEDTLS_ECP_DP_SECP256R1, /*!< Domain parameters for the 256-bit curve defined by FIPS 186-4 and SEC1. */ + MBEDTLS_ECP_DP_SECP384R1, /*!< Domain parameters for the 384-bit curve defined by FIPS 186-4 and SEC1. */ + MBEDTLS_ECP_DP_SECP521R1, /*!< Domain parameters for the 521-bit curve defined by FIPS 186-4 and SEC1. */ + MBEDTLS_ECP_DP_BP256R1, /*!< Domain parameters for 256-bit Brainpool curve. */ + MBEDTLS_ECP_DP_BP384R1, /*!< Domain parameters for 384-bit Brainpool curve. */ + MBEDTLS_ECP_DP_BP512R1, /*!< Domain parameters for 512-bit Brainpool curve. */ + MBEDTLS_ECP_DP_CURVE25519, /*!< Domain parameters for Curve25519. */ + MBEDTLS_ECP_DP_SECP192K1, /*!< Domain parameters for 192-bit "Koblitz" curve. */ + MBEDTLS_ECP_DP_SECP224K1, /*!< Domain parameters for 224-bit "Koblitz" curve. */ + MBEDTLS_ECP_DP_SECP256K1, /*!< Domain parameters for 256-bit "Koblitz" curve. */ + MBEDTLS_ECP_DP_CURVE448, /*!< Domain parameters for Curve448. */ +} mbedtls_ecp_group_id; + +/** + * The number of supported curves, plus one for #MBEDTLS_ECP_DP_NONE. + */ +#define MBEDTLS_ECP_DP_MAX 14 + +/* + * Curve types + */ +typedef enum { + MBEDTLS_ECP_TYPE_NONE = 0, + MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS, /* y^2 = x^3 + a x + b */ + MBEDTLS_ECP_TYPE_MONTGOMERY, /* y^2 = x^3 + a x^2 + x */ +} 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. + */ +typedef struct mbedtls_ecp_curve_info { + mbedtls_ecp_group_id grp_id; /*!< An internal identifier. */ + uint16_t tls_id; /*!< The TLS NamedCurve identifier. */ + uint16_t bit_size; /*!< The curve size in bits. */ + const char *name; /*!< A human-friendly name. */ +} 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. + */ +typedef struct mbedtls_ecp_point { + mbedtls_mpi MBEDTLS_PRIVATE(X); /*!< The X coordinate of the ECP point. */ + mbedtls_mpi MBEDTLS_PRIVATE(Y); /*!< The Y coordinate of the ECP point. */ + mbedtls_mpi MBEDTLS_PRIVATE(Z); /*!< The Z coordinate of the ECP point. */ +} +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 approximative 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. + */ +typedef struct mbedtls_ecp_group { + mbedtls_ecp_group_id id; /*!< An internal group identifier. */ + mbedtls_mpi P; /*!< The prime modulus of the base field. */ + mbedtls_mpi A; /*!< For Short Weierstrass: \p A in the equation. Note that + \p A is not set to the authentic value in some cases. + Refer to detailed description of ::mbedtls_ecp_group if + using domain parameters in the structure. + For Montgomery curves: <code>(A + 2) / 4</code>. */ + mbedtls_mpi B; /*!< For Short Weierstrass: \p B in the equation. + For Montgomery curves: unused. */ + mbedtls_ecp_point G; /*!< The generator of the subgroup used. */ + mbedtls_mpi N; /*!< The order of \p G. */ + size_t pbits; /*!< The number of bits in \p P.*/ + size_t nbits; /*!< For Short Weierstrass: The number of bits in \p P. + For Montgomery curves: the number of bits in the + private keys. */ + /* End of public fields */ + + unsigned int MBEDTLS_PRIVATE(h); /*!< \internal 1 if the constants are static. */ + int(*MBEDTLS_PRIVATE(modp))(mbedtls_mpi *); /*!< The function for fast pseudo-reduction + mod \p P (see above).*/ + int(*MBEDTLS_PRIVATE(t_pre))(mbedtls_ecp_point *, void *); /*!< Unused. */ + int(*MBEDTLS_PRIVATE(t_post))(mbedtls_ecp_point *, void *); /*!< Unused. */ + void *MBEDTLS_PRIVATE(t_data); /*!< Unused. */ + mbedtls_ecp_point *MBEDTLS_PRIVATE(T); /*!< Pre-computed points for ecp_mul_comb(). */ + size_t MBEDTLS_PRIVATE(T_size); /*!< The number of dynamic allocated pre-computed points. */ +} +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 4 /**< The maximum window size used. */ +#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 1 /**< Enable fixed-point speed-up. */ +#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 1 +/* Note: the curves must be listed in DECREASING size! */ +#elif defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 521 +#elif defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 512 +#elif defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 448 +#elif defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 384 +#elif defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 384 +#elif defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 256 +#elif defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 256 +#elif defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 256 +#elif defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 255 +#elif defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 225 // n is slightly above 2^224 +#elif defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 224 +#elif defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 192 +#elif defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) +#define MBEDTLS_ECP_MAX_BITS 192 +#else /* !MBEDTLS_ECP_LIGHT */ +#error "Missing definition of MBEDTLS_ECP_MAX_BITS" +#endif /* !MBEDTLS_ECP_LIGHT */ + +#define MBEDTLS_ECP_MAX_BYTES ((MBEDTLS_ECP_MAX_BITS + 7) / 8) +#define MBEDTLS_ECP_MAX_PT_LEN (2 * MBEDTLS_ECP_MAX_BYTES + 1) + +#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 3 /*!< basic ops count for ecp_check_pubkey() */ +#define MBEDTLS_ECP_OPS_DBL 8 /*!< basic ops count for ecp_double_jac() */ +#define MBEDTLS_ECP_OPS_ADD 11 /*!< basic ops count for see ecp_add_mixed() */ +#define MBEDTLS_ECP_OPS_INV 120 /*!< empirical equivalent for mpi_mod_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(ops) \ + MBEDTLS_MPI_CHK(mbedtls_ecp_check_budget(grp, rs_ctx, \ + (unsigned) (ops))); + +#else /* MBEDTLS_ECP_RESTARTABLE */ + +#define MBEDTLS_ECP_BUDGET(ops) /* no-op; for compatibility */ + +/* We want to declare restartable versions of existing functions anyway */ +typedef void 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. + */ +typedef struct mbedtls_ecp_keypair { + mbedtls_ecp_group MBEDTLS_PRIVATE(grp); /*!< Elliptic curve and base point */ + mbedtls_mpi MBEDTLS_PRIVATE(d); /*!< our secret value */ + mbedtls_ecp_point MBEDTLS_PRIVATE(Q); /*!< our public value */ +} +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 0 +/** + * 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 1 + +/* + * Some other constants from RFC 4492 + */ +#define MBEDTLS_ECP_TLS_NAMED_CURVE 3 /**< The named_curve of ECCurveType. */ + +#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) +{ + return grp->A.MBEDTLS_PRIVATE(p) == NULL; +} + +/** + * \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 This function reads an elliptic curve private key. + * + * \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); + +/** + * \brief This function exports an elliptic curve private key. + * + * \param key The private key. + * \param buf The output buffer for containing the binary representation + * of the key. (Big endian integer for Weierstrass curves, byte + * string for Montgomery curves.) + * \param buflen The total length of the buffer in bytes. + * + * \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_FEATURE_UNAVAILABLE if the operation for + * the group is not implemented. + * \return Another negative error code on different kinds of failure. + */ +int mbedtls_ecp_write_key(mbedtls_ecp_keypair *key, + 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 This function exports generic key-pair parameters. + * + * \param key The key pair to export from. + * \param grp Slot for exported ECP group. + * It must point to an initialized ECP group. + * \param d Slot for the exported secret value. + * It must point to an initialized mpi. + * \param Q Slot for the exported public value. + * It must 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 */ |