1 /** 2 * \file ecp.h 3 * 4 * \brief This file provides an API for Elliptic Curves over GF(P) (ECP). 5 * 6 * The use of ECP in cryptography and TLS is defined in 7 * <em>Standards for Efficient Cryptography Group (SECG): SEC1 8 * Elliptic Curve Cryptography</em> and 9 * <em>RFC-4492: Elliptic Curve Cryptography (ECC) Cipher Suites 10 * for Transport Layer Security (TLS)</em>. 11 * 12 * <em>RFC-2409: The Internet Key Exchange (IKE)</em> defines ECP 13 * group types. 14 * 15 */ 16 17 /* 18 * Copyright The Mbed TLS Contributors 19 * SPDX-License-Identifier: Apache-2.0 20 * 21 * Licensed under the Apache License, Version 2.0 (the "License"); you may 22 * not use this file except in compliance with the License. 23 * You may obtain a copy of the License at 24 * 25 * http://www.apache.org/licenses/LICENSE-2.0 26 * 27 * Unless required by applicable law or agreed to in writing, software 28 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 29 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 30 * See the License for the specific language governing permissions and 31 * limitations under the License. 32 */ 33 34 #ifndef MBEDTLS_ECP_H 35 #define MBEDTLS_ECP_H 36 37 #if !defined(MBEDTLS_CONFIG_FILE) 38 #include "mbedtls/config.h" 39 #else 40 #include MBEDTLS_CONFIG_FILE 41 #endif 42 43 #include "mbedtls/bignum.h" 44 45 /* 46 * ECP error codes 47 */ 48 #define MBEDTLS_ERR_ECP_BAD_INPUT_DATA -0x4F80 /**< Bad input parameters to function. */ 49 #define MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL -0x4F00 /**< The buffer is too small to write to. */ 50 #define MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE -0x4E80 /**< The requested feature is not available, for example, the requested curve is not supported. */ 51 #define MBEDTLS_ERR_ECP_VERIFY_FAILED -0x4E00 /**< The signature is not valid. */ 52 #define MBEDTLS_ERR_ECP_ALLOC_FAILED -0x4D80 /**< Memory allocation failed. */ 53 #define MBEDTLS_ERR_ECP_RANDOM_FAILED -0x4D00 /**< Generation of random value, such as ephemeral key, failed. */ 54 #define MBEDTLS_ERR_ECP_INVALID_KEY -0x4C80 /**< Invalid private or public key. */ 55 #define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH -0x4C00 /**< The buffer contains a valid signature followed by more data. */ 56 57 /* MBEDTLS_ERR_ECP_HW_ACCEL_FAILED is deprecated and should not be used. */ 58 #define MBEDTLS_ERR_ECP_HW_ACCEL_FAILED -0x4B80 /**< The ECP hardware accelerator failed. */ 59 60 #define MBEDTLS_ERR_ECP_IN_PROGRESS -0x4B00 /**< Operation in progress, call again with the same parameters to continue. */ 61 62 /* Flags indicating whether to include code that is specific to certain 63 * types of curves. These flags are for internal library use only. */ 64 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || \ 65 defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) || \ 66 defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \ 67 defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) || \ 68 defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) || \ 69 defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) || \ 70 defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) || \ 71 defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) || \ 72 defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) || \ 73 defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) || \ 74 defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED) 75 #define MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED 76 #endif 77 #if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \ 78 defined(MBEDTLS_ECP_DP_CURVE448_ENABLED) 79 #define MBEDTLS_ECP_MONTGOMERY_ENABLED 80 #endif 81 82 #ifdef __cplusplus 83 extern "C" { 84 #endif 85 86 /** 87 * Domain-parameter identifiers: curve, subgroup, and generator. 88 * 89 * \note Only curves over prime fields are supported. 90 * 91 * \warning This library does not support validation of arbitrary domain 92 * parameters. Therefore, only standardized domain parameters from trusted 93 * sources should be used. See mbedtls_ecp_group_load(). 94 */ 95 /* Note: when adding a new curve: 96 * - Add it at the end of this enum, otherwise you'll break the ABI by 97 * changing the numerical value for existing curves. 98 * - Increment MBEDTLS_ECP_DP_MAX below if needed. 99 * - Add the corresponding MBEDTLS_ECP_DP_xxx_ENABLED macro definition to 100 * config.h. 101 * - List the curve as a dependency of MBEDTLS_ECP_C and 102 * MBEDTLS_ECDSA_C if supported in check_config.h. 103 * - Add the curve to the appropriate curve type macro 104 * MBEDTLS_ECP_yyy_ENABLED above. 105 * - Add the necessary definitions to ecp_curves.c. 106 * - Add the curve to the ecp_supported_curves array in ecp.c. 107 * - Add the curve to applicable profiles in x509_crt.c if applicable. 108 */ 109 typedef enum 110 { 111 MBEDTLS_ECP_DP_NONE = 0, /*!< Curve not defined. */ 112 MBEDTLS_ECP_DP_SECP192R1, /*!< Domain parameters for the 192-bit curve defined by FIPS 186-4 and SEC1. */ 113 MBEDTLS_ECP_DP_SECP224R1, /*!< Domain parameters for the 224-bit curve defined by FIPS 186-4 and SEC1. */ 114 MBEDTLS_ECP_DP_SECP256R1, /*!< Domain parameters for the 256-bit curve defined by FIPS 186-4 and SEC1. */ 115 MBEDTLS_ECP_DP_SECP384R1, /*!< Domain parameters for the 384-bit curve defined by FIPS 186-4 and SEC1. */ 116 MBEDTLS_ECP_DP_SECP521R1, /*!< Domain parameters for the 521-bit curve defined by FIPS 186-4 and SEC1. */ 117 MBEDTLS_ECP_DP_BP256R1, /*!< Domain parameters for 256-bit Brainpool curve. */ 118 MBEDTLS_ECP_DP_BP384R1, /*!< Domain parameters for 384-bit Brainpool curve. */ 119 MBEDTLS_ECP_DP_BP512R1, /*!< Domain parameters for 512-bit Brainpool curve. */ 120 MBEDTLS_ECP_DP_CURVE25519, /*!< Domain parameters for Curve25519. */ 121 MBEDTLS_ECP_DP_SECP192K1, /*!< Domain parameters for 192-bit "Koblitz" curve. */ 122 MBEDTLS_ECP_DP_SECP224K1, /*!< Domain parameters for 224-bit "Koblitz" curve. */ 123 MBEDTLS_ECP_DP_SECP256K1, /*!< Domain parameters for 256-bit "Koblitz" curve. */ 124 MBEDTLS_ECP_DP_CURVE448, /*!< Domain parameters for Curve448. */ 125 } mbedtls_ecp_group_id; 126 127 /** 128 * The number of supported curves, plus one for #MBEDTLS_ECP_DP_NONE. 129 * 130 * \note Montgomery curves are currently excluded. 131 */ 132 #define MBEDTLS_ECP_DP_MAX 12 133 134 /* 135 * Curve types 136 */ 137 typedef enum 138 { 139 MBEDTLS_ECP_TYPE_NONE = 0, 140 MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS, /* y^2 = x^3 + a x + b */ 141 MBEDTLS_ECP_TYPE_MONTGOMERY, /* y^2 = x^3 + a x^2 + x */ 142 } mbedtls_ecp_curve_type; 143 144 /** 145 * Curve information, for use by other modules. 146 */ 147 typedef struct mbedtls_ecp_curve_info 148 { 149 mbedtls_ecp_group_id grp_id; /*!< An internal identifier. */ 150 uint16_t tls_id; /*!< The TLS NamedCurve identifier. */ 151 uint16_t bit_size; /*!< The curve size in bits. */ 152 const char *name; /*!< A human-friendly name. */ 153 } mbedtls_ecp_curve_info; 154 155 /** 156 * \brief The ECP point structure, in Jacobian coordinates. 157 * 158 * \note All functions expect and return points satisfying 159 * the following condition: <code>Z == 0</code> or 160 * <code>Z == 1</code>. Other values of \p Z are 161 * used only by internal functions. 162 * The point is zero, or "at infinity", if <code>Z == 0</code>. 163 * Otherwise, \p X and \p Y are its standard (affine) 164 * coordinates. 165 */ 166 typedef struct mbedtls_ecp_point 167 { 168 mbedtls_mpi X; /*!< The X coordinate of the ECP point. */ 169 mbedtls_mpi Y; /*!< The Y coordinate of the ECP point. */ 170 mbedtls_mpi Z; /*!< The Z coordinate of the ECP point. */ 171 } 172 mbedtls_ecp_point; 173 174 #if !defined(MBEDTLS_ECP_ALT) 175 /* 176 * default mbed TLS elliptic curve arithmetic implementation 177 * 178 * (in case MBEDTLS_ECP_ALT is defined then the developer has to provide an 179 * alternative implementation for the whole module and it will replace this 180 * one.) 181 */ 182 183 /** 184 * \brief The ECP group structure. 185 * 186 * We consider two types of curve equations: 187 * <ul><li>Short Weierstrass: <code>y^2 = x^3 + A x + B mod P</code> 188 * (SEC1 + RFC-4492)</li> 189 * <li>Montgomery: <code>y^2 = x^3 + A x^2 + x mod P</code> (Curve25519, 190 * Curve448)</li></ul> 191 * In both cases, the generator (\p G) for a prime-order subgroup is fixed. 192 * 193 * For Short Weierstrass, this subgroup is the whole curve, and its 194 * cardinality is denoted by \p N. Our code requires that \p N is an 195 * odd prime as mbedtls_ecp_mul() requires an odd number, and 196 * mbedtls_ecdsa_sign() requires that it is prime for blinding purposes. 197 * 198 * For Montgomery curves, we do not store \p A, but <code>(A + 2) / 4</code>, 199 * which is the quantity used in the formulas. Additionally, \p nbits is 200 * not the size of \p N but the required size for private keys. 201 * 202 * If \p modp is NULL, reduction modulo \p P is done using a generic algorithm. 203 * Otherwise, \p modp must point to a function that takes an \p mbedtls_mpi in the 204 * range of <code>0..2^(2*pbits)-1</code>, and transforms it in-place to an integer 205 * which is congruent mod \p P to the given MPI, and is close enough to \p pbits 206 * in size, so that it may be efficiently brought in the 0..P-1 range by a few 207 * additions or subtractions. Therefore, it is only an approximative modular 208 * reduction. It must return 0 on success and non-zero on failure. 209 * 210 * \note Alternative implementations must keep the group IDs distinct. If 211 * two group structures have the same ID, then they must be 212 * identical. 213 * 214 */ 215 typedef struct mbedtls_ecp_group 216 { 217 mbedtls_ecp_group_id id; /*!< An internal group identifier. */ 218 mbedtls_mpi P; /*!< The prime modulus of the base field. */ 219 mbedtls_mpi A; /*!< For Short Weierstrass: \p A in the equation. For 220 Montgomery curves: <code>(A + 2) / 4</code>. */ 221 mbedtls_mpi B; /*!< For Short Weierstrass: \p B in the equation. 222 For Montgomery curves: unused. */ 223 mbedtls_ecp_point G; /*!< The generator of the subgroup used. */ 224 mbedtls_mpi N; /*!< The order of \p G. */ 225 size_t pbits; /*!< The number of bits in \p P.*/ 226 size_t nbits; /*!< For Short Weierstrass: The number of bits in \p P. 227 For Montgomery curves: the number of bits in the 228 private keys. */ 229 unsigned int h; /*!< \internal 1 if the constants are static. */ 230 int (*modp)(mbedtls_mpi *); /*!< The function for fast pseudo-reduction 231 mod \p P (see above).*/ 232 int (*t_pre)(mbedtls_ecp_point *, void *); /*!< Unused. */ 233 int (*t_post)(mbedtls_ecp_point *, void *); /*!< Unused. */ 234 void *t_data; /*!< Unused. */ 235 mbedtls_ecp_point *T; /*!< Pre-computed points for ecp_mul_comb(). */ 236 size_t T_size; /*!< The number of pre-computed points. */ 237 } 238 mbedtls_ecp_group; 239 240 /** 241 * \name SECTION: Module settings 242 * 243 * The configuration options you can set for this module are in this section. 244 * Either change them in config.h, or define them using the compiler command line. 245 * \{ 246 */ 247 248 #if !defined(MBEDTLS_ECP_MAX_BITS) 249 /** 250 * The maximum size of the groups, that is, of \c N and \c P. 251 */ 252 #define MBEDTLS_ECP_MAX_BITS 521 /**< The maximum size of groups, in bits. */ 253 #endif 254 255 #define MBEDTLS_ECP_MAX_BYTES ( ( MBEDTLS_ECP_MAX_BITS + 7 ) / 8 ) 256 #define MBEDTLS_ECP_MAX_PT_LEN ( 2 * MBEDTLS_ECP_MAX_BYTES + 1 ) 257 258 #if !defined(MBEDTLS_ECP_WINDOW_SIZE) 259 /* 260 * Maximum "window" size used for point multiplication. 261 * Default: 6. 262 * Minimum value: 2. Maximum value: 7. 263 * 264 * Result is an array of at most ( 1 << ( MBEDTLS_ECP_WINDOW_SIZE - 1 ) ) 265 * points used for point multiplication. This value is directly tied to EC 266 * peak memory usage, so decreasing it by one should roughly cut memory usage 267 * by two (if large curves are in use). 268 * 269 * Reduction in size may reduce speed, but larger curves are impacted first. 270 * Sample performances (in ECDHE handshakes/s, with FIXED_POINT_OPTIM = 1): 271 * w-size: 6 5 4 3 2 272 * 521 145 141 135 120 97 273 * 384 214 209 198 177 146 274 * 256 320 320 303 262 226 275 * 224 475 475 453 398 342 276 * 192 640 640 633 587 476 277 */ 278 #define MBEDTLS_ECP_WINDOW_SIZE 6 /**< The maximum window size used. */ 279 #endif /* MBEDTLS_ECP_WINDOW_SIZE */ 280 281 #if !defined(MBEDTLS_ECP_FIXED_POINT_OPTIM) 282 /* 283 * Trade memory for speed on fixed-point multiplication. 284 * 285 * This speeds up repeated multiplication of the generator (that is, the 286 * multiplication in ECDSA signatures, and half of the multiplications in 287 * ECDSA verification and ECDHE) by a factor roughly 3 to 4. 288 * 289 * The cost is increasing EC peak memory usage by a factor roughly 2. 290 * 291 * Change this value to 0 to reduce peak memory usage. 292 */ 293 #define MBEDTLS_ECP_FIXED_POINT_OPTIM 1 /**< Enable fixed-point speed-up. */ 294 #endif /* MBEDTLS_ECP_FIXED_POINT_OPTIM */ 295 296 /* \} name SECTION: Module settings */ 297 298 #else /* MBEDTLS_ECP_ALT */ 299 #include "ecp_alt.h" 300 #endif /* MBEDTLS_ECP_ALT */ 301 302 #if defined(MBEDTLS_ECP_RESTARTABLE) 303 304 /** 305 * \brief Internal restart context for multiplication 306 * 307 * \note Opaque struct 308 */ 309 typedef struct mbedtls_ecp_restart_mul mbedtls_ecp_restart_mul_ctx; 310 311 /** 312 * \brief Internal restart context for ecp_muladd() 313 * 314 * \note Opaque struct 315 */ 316 typedef struct mbedtls_ecp_restart_muladd mbedtls_ecp_restart_muladd_ctx; 317 318 /** 319 * \brief General context for resuming ECC operations 320 */ 321 typedef struct 322 { 323 unsigned ops_done; /*!< current ops count */ 324 unsigned depth; /*!< call depth (0 = top-level) */ 325 mbedtls_ecp_restart_mul_ctx *rsm; /*!< ecp_mul_comb() sub-context */ 326 mbedtls_ecp_restart_muladd_ctx *ma; /*!< ecp_muladd() sub-context */ 327 } mbedtls_ecp_restart_ctx; 328 329 /* 330 * Operation counts for restartable functions 331 */ 332 #define MBEDTLS_ECP_OPS_CHK 3 /*!< basic ops count for ecp_check_pubkey() */ 333 #define MBEDTLS_ECP_OPS_DBL 8 /*!< basic ops count for ecp_double_jac() */ 334 #define MBEDTLS_ECP_OPS_ADD 11 /*!< basic ops count for see ecp_add_mixed() */ 335 #define MBEDTLS_ECP_OPS_INV 120 /*!< empirical equivalent for mpi_mod_inv() */ 336 337 /** 338 * \brief Internal; for restartable functions in other modules. 339 * Check and update basic ops budget. 340 * 341 * \param grp Group structure 342 * \param rs_ctx Restart context 343 * \param ops Number of basic ops to do 344 * 345 * \return \c 0 if doing \p ops basic ops is still allowed, 346 * \return #MBEDTLS_ERR_ECP_IN_PROGRESS otherwise. 347 */ 348 int mbedtls_ecp_check_budget( const mbedtls_ecp_group *grp, 349 mbedtls_ecp_restart_ctx *rs_ctx, 350 unsigned ops ); 351 352 /* Utility macro for checking and updating ops budget */ 353 #define MBEDTLS_ECP_BUDGET( ops ) \ 354 MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, rs_ctx, \ 355 (unsigned) (ops) ) ); 356 357 #else /* MBEDTLS_ECP_RESTARTABLE */ 358 359 #define MBEDTLS_ECP_BUDGET( ops ) /* no-op; for compatibility */ 360 361 /* We want to declare restartable versions of existing functions anyway */ 362 typedef void mbedtls_ecp_restart_ctx; 363 364 #endif /* MBEDTLS_ECP_RESTARTABLE */ 365 366 /** 367 * \brief The ECP key-pair structure. 368 * 369 * A generic key-pair that may be used for ECDSA and fixed ECDH, for example. 370 * 371 * \note Members are deliberately in the same order as in the 372 * ::mbedtls_ecdsa_context structure. 373 */ 374 typedef struct mbedtls_ecp_keypair 375 { 376 mbedtls_ecp_group grp; /*!< Elliptic curve and base point */ 377 mbedtls_mpi d; /*!< our secret value */ 378 mbedtls_ecp_point Q; /*!< our public value */ 379 } 380 mbedtls_ecp_keypair; 381 382 /* 383 * Point formats, from RFC 4492's enum ECPointFormat 384 */ 385 #define MBEDTLS_ECP_PF_UNCOMPRESSED 0 /**< Uncompressed point format. */ 386 #define MBEDTLS_ECP_PF_COMPRESSED 1 /**< Compressed point format. */ 387 388 /* 389 * Some other constants from RFC 4492 390 */ 391 #define MBEDTLS_ECP_TLS_NAMED_CURVE 3 /**< The named_curve of ECCurveType. */ 392 393 #if defined(MBEDTLS_ECP_RESTARTABLE) 394 /** 395 * \brief Set the maximum number of basic operations done in a row. 396 * 397 * If more operations are needed to complete a computation, 398 * #MBEDTLS_ERR_ECP_IN_PROGRESS will be returned by the 399 * function performing the computation. It is then the 400 * caller's responsibility to either call again with the same 401 * parameters until it returns 0 or an error code; or to free 402 * the restart context if the operation is to be aborted. 403 * 404 * It is strictly required that all input parameters and the 405 * restart context be the same on successive calls for the 406 * same operation, but output parameters need not be the 407 * same; they must not be used until the function finally 408 * returns 0. 409 * 410 * This only applies to functions whose documentation 411 * mentions they may return #MBEDTLS_ERR_ECP_IN_PROGRESS (or 412 * #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS for functions in the 413 * SSL module). For functions that accept a "restart context" 414 * argument, passing NULL disables restart and makes the 415 * function equivalent to the function with the same name 416 * with \c _restartable removed. For functions in the ECDH 417 * module, restart is disabled unless the function accepts 418 * an "ECDH context" argument and 419 * mbedtls_ecdh_enable_restart() was previously called on 420 * that context. For function in the SSL module, restart is 421 * only enabled for specific sides and key exchanges 422 * (currently only for clients and ECDHE-ECDSA). 423 * 424 * \param max_ops Maximum number of basic operations done in a row. 425 * Default: 0 (unlimited). 426 * Lower (non-zero) values mean ECC functions will block for 427 * a lesser maximum amount of time. 428 * 429 * \note A "basic operation" is defined as a rough equivalent of a 430 * multiplication in GF(p) for the NIST P-256 curve. 431 * As an indication, with default settings, a scalar 432 * multiplication (full run of \c mbedtls_ecp_mul()) is: 433 * - about 3300 basic operations for P-256 434 * - about 9400 basic operations for P-384 435 * 436 * \note Very low values are not always respected: sometimes 437 * functions need to block for a minimum number of 438 * operations, and will do so even if max_ops is set to a 439 * lower value. That minimum depends on the curve size, and 440 * can be made lower by decreasing the value of 441 * \c MBEDTLS_ECP_WINDOW_SIZE. As an indication, here is the 442 * lowest effective value for various curves and values of 443 * that parameter (w for short): 444 * w=6 w=5 w=4 w=3 w=2 445 * P-256 208 208 160 136 124 446 * P-384 682 416 320 272 248 447 * P-521 1364 832 640 544 496 448 * 449 * \note This setting is currently ignored by Curve25519. 450 */ 451 void mbedtls_ecp_set_max_ops( unsigned max_ops ); 452 453 /** 454 * \brief Check if restart is enabled (max_ops != 0) 455 * 456 * \return \c 0 if \c max_ops == 0 (restart disabled) 457 * \return \c 1 otherwise (restart enabled) 458 */ 459 int mbedtls_ecp_restart_is_enabled( void ); 460 #endif /* MBEDTLS_ECP_RESTARTABLE */ 461 462 /* 463 * Get the type of a curve 464 */ 465 mbedtls_ecp_curve_type mbedtls_ecp_get_type( const mbedtls_ecp_group *grp ); 466 467 /** 468 * \brief This function retrieves the information defined in 469 * mbedtls_ecp_curve_info() for all supported curves in order 470 * of preference. 471 * 472 * \note This function returns information about all curves 473 * supported by the library. Some curves may not be 474 * supported for all algorithms. Call mbedtls_ecdh_can_do() 475 * or mbedtls_ecdsa_can_do() to check if a curve is 476 * supported for ECDH or ECDSA. 477 * 478 * \return A statically allocated array. The last entry is 0. 479 */ 480 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_list( void ); 481 482 /** 483 * \brief This function retrieves the list of internal group 484 * identifiers of all supported curves in the order of 485 * preference. 486 * 487 * \note This function returns information about all curves 488 * supported by the library. Some curves may not be 489 * supported for all algorithms. Call mbedtls_ecdh_can_do() 490 * or mbedtls_ecdsa_can_do() to check if a curve is 491 * supported for ECDH or ECDSA. 492 * 493 * \return A statically allocated array, 494 * terminated with MBEDTLS_ECP_DP_NONE. 495 */ 496 const mbedtls_ecp_group_id *mbedtls_ecp_grp_id_list( void ); 497 498 /** 499 * \brief This function retrieves curve information from an internal 500 * group identifier. 501 * 502 * \param grp_id An \c MBEDTLS_ECP_DP_XXX value. 503 * 504 * \return The associated curve information on success. 505 * \return NULL on failure. 506 */ 507 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_grp_id( mbedtls_ecp_group_id grp_id ); 508 509 /** 510 * \brief This function retrieves curve information from a TLS 511 * NamedCurve value. 512 * 513 * \param tls_id An \c MBEDTLS_ECP_DP_XXX value. 514 * 515 * \return The associated curve information on success. 516 * \return NULL on failure. 517 */ 518 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_tls_id( uint16_t tls_id ); 519 520 /** 521 * \brief This function retrieves curve information from a 522 * human-readable name. 523 * 524 * \param name The human-readable name. 525 * 526 * \return The associated curve information on success. 527 * \return NULL on failure. 528 */ 529 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_name( const char *name ); 530 531 /** 532 * \brief This function initializes a point as zero. 533 * 534 * \param pt The point to initialize. 535 */ 536 void mbedtls_ecp_point_init( mbedtls_ecp_point *pt ); 537 538 /** 539 * \brief This function initializes an ECP group context 540 * without loading any domain parameters. 541 * 542 * \note After this function is called, domain parameters 543 * for various ECP groups can be loaded through the 544 * mbedtls_ecp_group_load() or mbedtls_ecp_tls_read_group() 545 * functions. 546 */ 547 void mbedtls_ecp_group_init( mbedtls_ecp_group *grp ); 548 549 /** 550 * \brief This function initializes a key pair as an invalid one. 551 * 552 * \param key The key pair to initialize. 553 */ 554 void mbedtls_ecp_keypair_init( mbedtls_ecp_keypair *key ); 555 556 /** 557 * \brief This function frees the components of a point. 558 * 559 * \param pt The point to free. 560 */ 561 void mbedtls_ecp_point_free( mbedtls_ecp_point *pt ); 562 563 /** 564 * \brief This function frees the components of an ECP group. 565 * 566 * \param grp The group to free. This may be \c NULL, in which 567 * case this function returns immediately. If it is not 568 * \c NULL, it must point to an initialized ECP group. 569 */ 570 void mbedtls_ecp_group_free( mbedtls_ecp_group *grp ); 571 572 /** 573 * \brief This function frees the components of a key pair. 574 * 575 * \param key The key pair to free. This may be \c NULL, in which 576 * case this function returns immediately. If it is not 577 * \c NULL, it must point to an initialized ECP key pair. 578 */ 579 void mbedtls_ecp_keypair_free( mbedtls_ecp_keypair *key ); 580 581 #if defined(MBEDTLS_ECP_RESTARTABLE) 582 /** 583 * \brief Initialize a restart context. 584 * 585 * \param ctx The restart context to initialize. This must 586 * not be \c NULL. 587 */ 588 void mbedtls_ecp_restart_init( mbedtls_ecp_restart_ctx *ctx ); 589 590 /** 591 * \brief Free the components of a restart context. 592 * 593 * \param ctx The restart context to free. This may be \c NULL, in which 594 * case this function returns immediately. If it is not 595 * \c NULL, it must point to an initialized restart context. 596 */ 597 void mbedtls_ecp_restart_free( mbedtls_ecp_restart_ctx *ctx ); 598 #endif /* MBEDTLS_ECP_RESTARTABLE */ 599 600 /** 601 * \brief This function copies the contents of point \p Q into 602 * point \p P. 603 * 604 * \param P The destination point. This must be initialized. 605 * \param Q The source point. This must be initialized. 606 * 607 * \return \c 0 on success. 608 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 609 * \return Another negative error code for other kinds of failure. 610 */ 611 int mbedtls_ecp_copy( mbedtls_ecp_point *P, const mbedtls_ecp_point *Q ); 612 613 /** 614 * \brief This function copies the contents of group \p src into 615 * group \p dst. 616 * 617 * \param dst The destination group. This must be initialized. 618 * \param src The source group. This must be initialized. 619 * 620 * \return \c 0 on success. 621 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 622 * \return Another negative error code on other kinds of failure. 623 */ 624 int mbedtls_ecp_group_copy( mbedtls_ecp_group *dst, 625 const mbedtls_ecp_group *src ); 626 627 /** 628 * \brief This function sets a point to the point at infinity. 629 * 630 * \param pt The point to set. This must be initialized. 631 * 632 * \return \c 0 on success. 633 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 634 * \return Another negative error code on other kinds of failure. 635 */ 636 int mbedtls_ecp_set_zero( mbedtls_ecp_point *pt ); 637 638 /** 639 * \brief This function checks if a point is the point at infinity. 640 * 641 * \param pt The point to test. This must be initialized. 642 * 643 * \return \c 1 if the point is zero. 644 * \return \c 0 if the point is non-zero. 645 * \return A negative error code on failure. 646 */ 647 int mbedtls_ecp_is_zero( mbedtls_ecp_point *pt ); 648 649 /** 650 * \brief This function compares two points. 651 * 652 * \note This assumes that the points are normalized. Otherwise, 653 * they may compare as "not equal" even if they are. 654 * 655 * \param P The first point to compare. This must be initialized. 656 * \param Q The second point to compare. This must be initialized. 657 * 658 * \return \c 0 if the points are equal. 659 * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the points are not equal. 660 */ 661 int mbedtls_ecp_point_cmp( const mbedtls_ecp_point *P, 662 const mbedtls_ecp_point *Q ); 663 664 /** 665 * \brief This function imports a non-zero point from two ASCII 666 * strings. 667 * 668 * \param P The destination point. This must be initialized. 669 * \param radix The numeric base of the input. 670 * \param x The first affine coordinate, as a null-terminated string. 671 * \param y The second affine coordinate, as a null-terminated string. 672 * 673 * \return \c 0 on success. 674 * \return An \c MBEDTLS_ERR_MPI_XXX error code on failure. 675 */ 676 int mbedtls_ecp_point_read_string( mbedtls_ecp_point *P, int radix, 677 const char *x, const char *y ); 678 679 /** 680 * \brief This function exports a point into unsigned binary data. 681 * 682 * \param grp The group to which the point should belong. 683 * This must be initialized and have group parameters 684 * set, for example through mbedtls_ecp_group_load(). 685 * \param P The point to export. This must be initialized. 686 * \param format The point format. This must be either 687 * #MBEDTLS_ECP_PF_COMPRESSED or #MBEDTLS_ECP_PF_UNCOMPRESSED. 688 * (For groups without these formats, this parameter is 689 * ignored. But it still has to be either of the above 690 * values.) 691 * \param olen The address at which to store the length of 692 * the output in Bytes. This must not be \c NULL. 693 * \param buf The output buffer. This must be a writable buffer 694 * of length \p buflen Bytes. 695 * \param buflen The length of the output buffer \p buf in Bytes. 696 * 697 * \return \c 0 on success. 698 * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the output buffer 699 * is too small to hold the point. 700 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the point format 701 * or the export for the given group is not implemented. 702 * \return Another negative error code on other kinds of failure. 703 */ 704 int mbedtls_ecp_point_write_binary( const mbedtls_ecp_group *grp, 705 const mbedtls_ecp_point *P, 706 int format, size_t *olen, 707 unsigned char *buf, size_t buflen ); 708 709 /** 710 * \brief This function imports a point from unsigned binary data. 711 * 712 * \note This function does not check that the point actually 713 * belongs to the given group, see mbedtls_ecp_check_pubkey() 714 * for that. 715 * 716 * \param grp The group to which the point should belong. 717 * This must be initialized and have group parameters 718 * set, for example through mbedtls_ecp_group_load(). 719 * \param P The destination context to import the point to. 720 * This must be initialized. 721 * \param buf The input buffer. This must be a readable buffer 722 * of length \p ilen Bytes. 723 * \param ilen The length of the input buffer \p buf in Bytes. 724 * 725 * \return \c 0 on success. 726 * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the input is invalid. 727 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 728 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the import for the 729 * given group is not implemented. 730 */ 731 int mbedtls_ecp_point_read_binary( const mbedtls_ecp_group *grp, 732 mbedtls_ecp_point *P, 733 const unsigned char *buf, size_t ilen ); 734 735 /** 736 * \brief This function imports a point from a TLS ECPoint record. 737 * 738 * \note On function return, \p *buf is updated to point immediately 739 * after the ECPoint record. 740 * 741 * \param grp The ECP group to use. 742 * This must be initialized and have group parameters 743 * set, for example through mbedtls_ecp_group_load(). 744 * \param pt The destination point. 745 * \param buf The address of the pointer to the start of the input buffer. 746 * \param len The length of the buffer. 747 * 748 * \return \c 0 on success. 749 * \return An \c MBEDTLS_ERR_MPI_XXX error code on initialization 750 * failure. 751 * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid. 752 */ 753 int mbedtls_ecp_tls_read_point( const mbedtls_ecp_group *grp, 754 mbedtls_ecp_point *pt, 755 const unsigned char **buf, size_t len ); 756 757 /** 758 * \brief This function exports a point as a TLS ECPoint record 759 * defined in RFC 4492, Section 5.4. 760 * 761 * \param grp The ECP group to use. 762 * This must be initialized and have group parameters 763 * set, for example through mbedtls_ecp_group_load(). 764 * \param pt The point to be exported. This must be initialized. 765 * \param format The point format to use. This must be either 766 * #MBEDTLS_ECP_PF_COMPRESSED or #MBEDTLS_ECP_PF_UNCOMPRESSED. 767 * \param olen The address at which to store the length in Bytes 768 * of the data written. 769 * \param buf The target buffer. This must be a writable buffer of 770 * length \p blen Bytes. 771 * \param blen The length of the target buffer \p buf in Bytes. 772 * 773 * \return \c 0 on success. 774 * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the input is invalid. 775 * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the target buffer 776 * is too small to hold the exported point. 777 * \return Another negative error code on other kinds of failure. 778 */ 779 int mbedtls_ecp_tls_write_point( const mbedtls_ecp_group *grp, 780 const mbedtls_ecp_point *pt, 781 int format, size_t *olen, 782 unsigned char *buf, size_t blen ); 783 784 /** 785 * \brief This function sets up an ECP group context 786 * from a standardized set of domain parameters. 787 * 788 * \note The index should be a value of the NamedCurve enum, 789 * as defined in <em>RFC-4492: Elliptic Curve Cryptography 790 * (ECC) Cipher Suites for Transport Layer Security (TLS)</em>, 791 * usually in the form of an \c MBEDTLS_ECP_DP_XXX macro. 792 * 793 * \param grp The group context to setup. This must be initialized. 794 * \param id The identifier of the domain parameter set to load. 795 * 796 * \return \c 0 on success. 797 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if \p id doesn't 798 * correspond to a known group. 799 * \return Another negative error code on other kinds of failure. 800 */ 801 int mbedtls_ecp_group_load( mbedtls_ecp_group *grp, mbedtls_ecp_group_id id ); 802 803 /** 804 * \brief This function sets up an ECP group context from a TLS 805 * ECParameters record as defined in RFC 4492, Section 5.4. 806 * 807 * \note The read pointer \p buf is updated to point right after 808 * the ECParameters record on exit. 809 * 810 * \param grp The group context to setup. This must be initialized. 811 * \param buf The address of the pointer to the start of the input buffer. 812 * \param len The length of the input buffer \c *buf in Bytes. 813 * 814 * \return \c 0 on success. 815 * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid. 816 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the group is not 817 * recognized. 818 * \return Another negative error code on other kinds of failure. 819 */ 820 int mbedtls_ecp_tls_read_group( mbedtls_ecp_group *grp, 821 const unsigned char **buf, size_t len ); 822 823 /** 824 * \brief This function extracts an elliptic curve group ID from a 825 * TLS ECParameters record as defined in RFC 4492, Section 5.4. 826 * 827 * \note The read pointer \p buf is updated to point right after 828 * the ECParameters record on exit. 829 * 830 * \param grp The address at which to store the group id. 831 * This must not be \c NULL. 832 * \param buf The address of the pointer to the start of the input buffer. 833 * \param len The length of the input buffer \c *buf in Bytes. 834 * 835 * \return \c 0 on success. 836 * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid. 837 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the group is not 838 * recognized. 839 * \return Another negative error code on other kinds of failure. 840 */ 841 int mbedtls_ecp_tls_read_group_id( mbedtls_ecp_group_id *grp, 842 const unsigned char **buf, 843 size_t len ); 844 /** 845 * \brief This function exports an elliptic curve as a TLS 846 * ECParameters record as defined in RFC 4492, Section 5.4. 847 * 848 * \param grp The ECP group to be exported. 849 * This must be initialized and have group parameters 850 * set, for example through mbedtls_ecp_group_load(). 851 * \param olen The address at which to store the number of Bytes written. 852 * This must not be \c NULL. 853 * \param buf The buffer to write to. This must be a writable buffer 854 * of length \p blen Bytes. 855 * \param blen The length of the output buffer \p buf in Bytes. 856 * 857 * \return \c 0 on success. 858 * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the output 859 * buffer is too small to hold the exported group. 860 * \return Another negative error code on other kinds of failure. 861 */ 862 int mbedtls_ecp_tls_write_group( const mbedtls_ecp_group *grp, 863 size_t *olen, 864 unsigned char *buf, size_t blen ); 865 866 /** 867 * \brief This function performs a scalar multiplication of a point 868 * by an integer: \p R = \p m * \p P. 869 * 870 * It is not thread-safe to use same group in multiple threads. 871 * 872 * \note To prevent timing attacks, this function 873 * executes the exact same sequence of base-field 874 * operations for any valid \p m. It avoids any if-branch or 875 * array index depending on the value of \p m. 876 * 877 * \note If \p f_rng is not NULL, it is used to randomize 878 * intermediate results to prevent potential timing attacks 879 * targeting these results. We recommend always providing 880 * a non-NULL \p f_rng. The overhead is negligible. 881 * Note: unless #MBEDTLS_ECP_NO_INTERNAL_RNG is defined, when 882 * \p f_rng is NULL, an internal RNG (seeded from the value 883 * of \p m) will be used instead. 884 * 885 * \param grp The ECP group to use. 886 * This must be initialized and have group parameters 887 * set, for example through mbedtls_ecp_group_load(). 888 * \param R The point in which to store the result of the calculation. 889 * This must be initialized. 890 * \param m The integer by which to multiply. This must be initialized. 891 * \param P The point to multiply. This must be initialized. 892 * \param f_rng The RNG function. This may be \c NULL if randomization 893 * of intermediate results isn't desired (discouraged). 894 * \param p_rng The RNG context to be passed to \p p_rng. 895 * 896 * \return \c 0 on success. 897 * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m is not a valid private 898 * key, or \p P is not a valid public key. 899 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 900 * \return Another negative error code on other kinds of failure. 901 */ 902 int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, 903 const mbedtls_mpi *m, const mbedtls_ecp_point *P, 904 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ); 905 906 /** 907 * \brief This function performs multiplication of a point by 908 * an integer: \p R = \p m * \p P in a restartable way. 909 * 910 * \see mbedtls_ecp_mul() 911 * 912 * \note This function does the same as \c mbedtls_ecp_mul(), but 913 * it can return early and restart according to the limit set 914 * with \c mbedtls_ecp_set_max_ops() to reduce blocking. 915 * 916 * \param grp The ECP group to use. 917 * This must be initialized and have group parameters 918 * set, for example through mbedtls_ecp_group_load(). 919 * \param R The point in which to store the result of the calculation. 920 * This must be initialized. 921 * \param m The integer by which to multiply. This must be initialized. 922 * \param P The point to multiply. This must be initialized. 923 * \param f_rng The RNG function. This may be \c NULL if randomization 924 * of intermediate results isn't desired (discouraged). 925 * \param p_rng The RNG context to be passed to \p p_rng. 926 * \param rs_ctx The restart context (NULL disables restart). 927 * 928 * \return \c 0 on success. 929 * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m is not a valid private 930 * key, or \p P is not a valid public key. 931 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 932 * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of 933 * operations was reached: see \c mbedtls_ecp_set_max_ops(). 934 * \return Another negative error code on other kinds of failure. 935 */ 936 int mbedtls_ecp_mul_restartable( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, 937 const mbedtls_mpi *m, const mbedtls_ecp_point *P, 938 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, 939 mbedtls_ecp_restart_ctx *rs_ctx ); 940 941 #if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED) 942 /** 943 * \brief This function performs multiplication and addition of two 944 * points by integers: \p R = \p m * \p P + \p n * \p Q 945 * 946 * It is not thread-safe to use same group in multiple threads. 947 * 948 * \note In contrast to mbedtls_ecp_mul(), this function does not 949 * guarantee a constant execution flow and timing. 950 * 951 * \note This function is only defined for short Weierstrass curves. 952 * It may not be included in builds without any short 953 * Weierstrass curve. 954 * 955 * \param grp The ECP group to use. 956 * This must be initialized and have group parameters 957 * set, for example through mbedtls_ecp_group_load(). 958 * \param R The point in which to store the result of the calculation. 959 * This must be initialized. 960 * \param m The integer by which to multiply \p P. 961 * This must be initialized. 962 * \param P The point to multiply by \p m. This must be initialized. 963 * \param n The integer by which to multiply \p Q. 964 * This must be initialized. 965 * \param Q The point to be multiplied by \p n. 966 * This must be initialized. 967 * 968 * \return \c 0 on success. 969 * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m or \p n are not 970 * valid private keys, or \p P or \p Q are not valid public 971 * keys. 972 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 973 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if \p grp does not 974 * designate a short Weierstrass curve. 975 * \return Another negative error code on other kinds of failure. 976 */ 977 int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R, 978 const mbedtls_mpi *m, const mbedtls_ecp_point *P, 979 const mbedtls_mpi *n, const mbedtls_ecp_point *Q ); 980 981 /** 982 * \brief This function performs multiplication and addition of two 983 * points by integers: \p R = \p m * \p P + \p n * \p Q in a 984 * restartable way. 985 * 986 * \see \c mbedtls_ecp_muladd() 987 * 988 * \note This function works the same as \c mbedtls_ecp_muladd(), 989 * but it can return early and restart according to the limit 990 * set with \c mbedtls_ecp_set_max_ops() to reduce blocking. 991 * 992 * \note This function is only defined for short Weierstrass curves. 993 * It may not be included in builds without any short 994 * Weierstrass curve. 995 * 996 * \param grp The ECP group to use. 997 * This must be initialized and have group parameters 998 * set, for example through mbedtls_ecp_group_load(). 999 * \param R The point in which to store the result of the calculation. 1000 * This must be initialized. 1001 * \param m The integer by which to multiply \p P. 1002 * This must be initialized. 1003 * \param P The point to multiply by \p m. This must be initialized. 1004 * \param n The integer by which to multiply \p Q. 1005 * This must be initialized. 1006 * \param Q The point to be multiplied by \p n. 1007 * This must be initialized. 1008 * \param rs_ctx The restart context (NULL disables restart). 1009 * 1010 * \return \c 0 on success. 1011 * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m or \p n are not 1012 * valid private keys, or \p P or \p Q are not valid public 1013 * keys. 1014 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory-allocation failure. 1015 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if \p grp does not 1016 * designate a short Weierstrass curve. 1017 * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of 1018 * operations was reached: see \c mbedtls_ecp_set_max_ops(). 1019 * \return Another negative error code on other kinds of failure. 1020 */ 1021 int mbedtls_ecp_muladd_restartable( 1022 mbedtls_ecp_group *grp, mbedtls_ecp_point *R, 1023 const mbedtls_mpi *m, const mbedtls_ecp_point *P, 1024 const mbedtls_mpi *n, const mbedtls_ecp_point *Q, 1025 mbedtls_ecp_restart_ctx *rs_ctx ); 1026 #endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */ 1027 1028 /** 1029 * \brief This function checks that a point is a valid public key 1030 * on this curve. 1031 * 1032 * It only checks that the point is non-zero, has 1033 * valid coordinates and lies on the curve. It does not verify 1034 * that it is indeed a multiple of \p G. This additional 1035 * check is computationally more expensive, is not required 1036 * by standards, and should not be necessary if the group 1037 * used has a small cofactor. In particular, it is useless for 1038 * the NIST groups which all have a cofactor of 1. 1039 * 1040 * \note This function uses bare components rather than an 1041 * ::mbedtls_ecp_keypair structure, to ease use with other 1042 * structures, such as ::mbedtls_ecdh_context or 1043 * ::mbedtls_ecdsa_context. 1044 * 1045 * \param grp The ECP group the point should belong to. 1046 * This must be initialized and have group parameters 1047 * set, for example through mbedtls_ecp_group_load(). 1048 * \param pt The point to check. This must be initialized. 1049 * 1050 * \return \c 0 if the point is a valid public key. 1051 * \return #MBEDTLS_ERR_ECP_INVALID_KEY if the point is not 1052 * a valid public key for the given curve. 1053 * \return Another negative error code on other kinds of failure. 1054 */ 1055 int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp, 1056 const mbedtls_ecp_point *pt ); 1057 1058 /** 1059 * \brief This function checks that an \p mbedtls_mpi is a 1060 * valid private key for this curve. 1061 * 1062 * \note This function uses bare components rather than an 1063 * ::mbedtls_ecp_keypair structure to ease use with other 1064 * structures, such as ::mbedtls_ecdh_context or 1065 * ::mbedtls_ecdsa_context. 1066 * 1067 * \param grp The ECP group the private key should belong to. 1068 * This must be initialized and have group parameters 1069 * set, for example through mbedtls_ecp_group_load(). 1070 * \param d The integer to check. This must be initialized. 1071 * 1072 * \return \c 0 if the point is a valid private key. 1073 * \return #MBEDTLS_ERR_ECP_INVALID_KEY if the point is not a valid 1074 * private key for the given curve. 1075 * \return Another negative error code on other kinds of failure. 1076 */ 1077 int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, 1078 const mbedtls_mpi *d ); 1079 1080 /** 1081 * \brief This function generates a private key. 1082 * 1083 * \param grp The ECP group to generate a private key for. 1084 * This must be initialized and have group parameters 1085 * set, for example through mbedtls_ecp_group_load(). 1086 * \param d The destination MPI (secret part). This must be initialized. 1087 * \param f_rng The RNG function. This must not be \c NULL. 1088 * \param p_rng The RNG parameter to be passed to \p f_rng. This may be 1089 * \c NULL if \p f_rng doesn't need a context argument. 1090 * 1091 * \return \c 0 on success. 1092 * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code 1093 * on failure. 1094 */ 1095 int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp, 1096 mbedtls_mpi *d, 1097 int (*f_rng)(void *, unsigned char *, size_t), 1098 void *p_rng ); 1099 1100 /** 1101 * \brief This function generates a keypair with a configurable base 1102 * point. 1103 * 1104 * \note This function uses bare components rather than an 1105 * ::mbedtls_ecp_keypair structure to ease use with other 1106 * structures, such as ::mbedtls_ecdh_context or 1107 * ::mbedtls_ecdsa_context. 1108 * 1109 * \param grp The ECP group to generate a key pair for. 1110 * This must be initialized and have group parameters 1111 * set, for example through mbedtls_ecp_group_load(). 1112 * \param G The base point to use. This must be initialized 1113 * and belong to \p grp. It replaces the default base 1114 * point \c grp->G used by mbedtls_ecp_gen_keypair(). 1115 * \param d The destination MPI (secret part). 1116 * This must be initialized. 1117 * \param Q The destination point (public part). 1118 * This must be initialized. 1119 * \param f_rng The RNG function. This must not be \c NULL. 1120 * \param p_rng The RNG context to be passed to \p f_rng. This may 1121 * be \c NULL if \p f_rng doesn't need a context argument. 1122 * 1123 * \return \c 0 on success. 1124 * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code 1125 * on failure. 1126 */ 1127 int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp, 1128 const mbedtls_ecp_point *G, 1129 mbedtls_mpi *d, mbedtls_ecp_point *Q, 1130 int (*f_rng)(void *, unsigned char *, size_t), 1131 void *p_rng ); 1132 1133 /** 1134 * \brief This function generates an ECP keypair. 1135 * 1136 * \note This function uses bare components rather than an 1137 * ::mbedtls_ecp_keypair structure to ease use with other 1138 * structures, such as ::mbedtls_ecdh_context or 1139 * ::mbedtls_ecdsa_context. 1140 * 1141 * \param grp The ECP group to generate a key pair for. 1142 * This must be initialized and have group parameters 1143 * set, for example through mbedtls_ecp_group_load(). 1144 * \param d The destination MPI (secret part). 1145 * This must be initialized. 1146 * \param Q The destination point (public part). 1147 * This must be initialized. 1148 * \param f_rng The RNG function. This must not be \c NULL. 1149 * \param p_rng The RNG context to be passed to \p f_rng. This may 1150 * be \c NULL if \p f_rng doesn't need a context argument. 1151 * 1152 * \return \c 0 on success. 1153 * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code 1154 * on failure. 1155 */ 1156 int mbedtls_ecp_gen_keypair( mbedtls_ecp_group *grp, mbedtls_mpi *d, 1157 mbedtls_ecp_point *Q, 1158 int (*f_rng)(void *, unsigned char *, size_t), 1159 void *p_rng ); 1160 1161 /** 1162 * \brief This function generates an ECP key. 1163 * 1164 * \param grp_id The ECP group identifier. 1165 * \param key The destination key. This must be initialized. 1166 * \param f_rng The RNG function to use. This must not be \c NULL. 1167 * \param p_rng The RNG context to be passed to \p f_rng. This may 1168 * be \c NULL if \p f_rng doesn't need a context argument. 1169 * 1170 * \return \c 0 on success. 1171 * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code 1172 * on failure. 1173 */ 1174 int mbedtls_ecp_gen_key( mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key, 1175 int (*f_rng)(void *, unsigned char *, size_t), 1176 void *p_rng ); 1177 1178 /** 1179 * \brief This function reads an elliptic curve private key. 1180 * 1181 * \param grp_id The ECP group identifier. 1182 * \param key The destination key. 1183 * \param buf The the buffer containing the binary representation of the 1184 * key. (Big endian integer for Weierstrass curves, byte 1185 * string for Montgomery curves.) 1186 * \param buflen The length of the buffer in bytes. 1187 * 1188 * \return \c 0 on success. 1189 * \return #MBEDTLS_ERR_ECP_INVALID_KEY error if the key is 1190 * invalid. 1191 * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed. 1192 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the operation for 1193 * the group is not implemented. 1194 * \return Another negative error code on different kinds of failure. 1195 */ 1196 int mbedtls_ecp_read_key( mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key, 1197 const unsigned char *buf, size_t buflen ); 1198 1199 /** 1200 * \brief This function exports an elliptic curve private key. 1201 * 1202 * \param key The private key. 1203 * \param buf The output buffer for containing the binary representation 1204 * of the key. (Big endian integer for Weierstrass curves, byte 1205 * string for Montgomery curves.) 1206 * \param buflen The total length of the buffer in bytes. 1207 * 1208 * \return \c 0 on success. 1209 * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the \p key 1210 representation is larger than the available space in \p buf. 1211 * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the operation for 1212 * the group is not implemented. 1213 * \return Another negative error code on different kinds of failure. 1214 */ 1215 int mbedtls_ecp_write_key( mbedtls_ecp_keypair *key, 1216 unsigned char *buf, size_t buflen ); 1217 1218 /** 1219 * \brief This function checks that the keypair objects 1220 * \p pub and \p prv have the same group and the 1221 * same public point, and that the private key in 1222 * \p prv is consistent with the public key. 1223 * 1224 * \param pub The keypair structure holding the public key. This 1225 * must be initialized. If it contains a private key, that 1226 * part is ignored. 1227 * \param prv The keypair structure holding the full keypair. 1228 * This must be initialized. 1229 * 1230 * \return \c 0 on success, meaning that the keys are valid and match. 1231 * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the keys are invalid or do not match. 1232 * \return An \c MBEDTLS_ERR_ECP_XXX or an \c MBEDTLS_ERR_MPI_XXX 1233 * error code on calculation failure. 1234 */ 1235 int mbedtls_ecp_check_pub_priv( const mbedtls_ecp_keypair *pub, 1236 const mbedtls_ecp_keypair *prv ); 1237 1238 #if defined(MBEDTLS_SELF_TEST) 1239 1240 /** 1241 * \brief The ECP checkup routine. 1242 * 1243 * \return \c 0 on success. 1244 * \return \c 1 on failure. 1245 */ 1246 int mbedtls_ecp_self_test( int verbose ); 1247 1248 #endif /* MBEDTLS_SELF_TEST */ 1249 1250 #ifdef __cplusplus 1251 } 1252 #endif 1253 1254 #endif /* ecp.h */ 1255