1 /** 2 * \file psa/crypto_se_driver.h 3 * \brief PSA external cryptoprocessor driver module 4 * 5 * This header declares types and function signatures for cryptography 6 * drivers that access key material via opaque references. 7 * This is meant for cryptoprocessors that have a separate key storage from the 8 * space in which the PSA Crypto implementation runs, typically secure 9 * elements (SEs). 10 * 11 * This file is part of the PSA Crypto Driver HAL (hardware abstraction layer), 12 * containing functions for driver developers to implement to enable hardware 13 * to be called in a standardized way by a PSA Cryptography API 14 * implementation. The functions comprising the driver HAL, which driver 15 * authors implement, are not intended to be called by application developers. 16 */ 17 18 /* 19 * Copyright The Mbed TLS Contributors 20 * SPDX-License-Identifier: Apache-2.0 21 * 22 * Licensed under the Apache License, Version 2.0 (the "License"); you may 23 * not use this file except in compliance with the License. 24 * You may obtain a copy of the License at 25 * 26 * http://www.apache.org/licenses/LICENSE-2.0 27 * 28 * Unless required by applicable law or agreed to in writing, software 29 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 30 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 31 * See the License for the specific language governing permissions and 32 * limitations under the License. 33 */ 34 #ifndef PSA_CRYPTO_SE_DRIVER_H 35 #define PSA_CRYPTO_SE_DRIVER_H 36 37 #include "crypto_driver_common.h" 38 39 #ifdef __cplusplus 40 extern "C" { 41 #endif 42 43 /** \defgroup se_init Secure element driver initialization 44 */ 45 /**@{*/ 46 47 /** \brief Driver context structure 48 * 49 * Driver functions receive a pointer to this structure. 50 * Each registered driver has one instance of this structure. 51 * 52 * Implementations must include the fields specified here and 53 * may include other fields. 54 */ 55 typedef struct { 56 /** A read-only pointer to the driver's persistent data. 57 * 58 * Drivers typically use this persistent data to keep track of 59 * which slot numbers are available. This is only a guideline: 60 * drivers may use the persistent data for any purpose, keeping 61 * in mind the restrictions on when the persistent data is saved 62 * to storage: the persistent data is only saved after calling 63 * certain functions that receive a writable pointer to the 64 * persistent data. 65 * 66 * The core allocates a memory buffer for the persistent data. 67 * The pointer is guaranteed to be suitably aligned for any data type, 68 * like a pointer returned by `malloc` (but the core can use any 69 * method to allocate the buffer, not necessarily `malloc`). 70 * 71 * The size of this buffer is in the \c persistent_data_size field of 72 * this structure. 73 * 74 * Before the driver is initialized for the first time, the content of 75 * the persistent data is all-bits-zero. After a driver upgrade, if the 76 * size of the persistent data has increased, the original data is padded 77 * on the right with zeros; if the size has decreased, the original data 78 * is truncated to the new size. 79 * 80 * This pointer is to read-only data. Only a few driver functions are 81 * allowed to modify the persistent data. These functions receive a 82 * writable pointer. These functions are: 83 * - psa_drv_se_t::p_init 84 * - psa_drv_se_key_management_t::p_allocate 85 * - psa_drv_se_key_management_t::p_destroy 86 * 87 * The PSA Cryptography core saves the persistent data from one 88 * session to the next. It does this before returning from API functions 89 * that call a driver method that is allowed to modify the persistent 90 * data, specifically: 91 * - psa_crypto_init() causes a call to psa_drv_se_t::p_init, and may call 92 * psa_drv_se_key_management_t::p_destroy to complete an action 93 * that was interrupted by a power failure. 94 * - Key creation functions cause a call to 95 * psa_drv_se_key_management_t::p_allocate, and may cause a call to 96 * psa_drv_se_key_management_t::p_destroy in case an error occurs. 97 * - psa_destroy_key() causes a call to 98 * psa_drv_se_key_management_t::p_destroy. 99 */ 100 const void *const persistent_data; 101 102 /** The size of \c persistent_data in bytes. 103 * 104 * This is always equal to the value of the `persistent_data_size` field 105 * of the ::psa_drv_se_t structure when the driver is registered. 106 */ 107 const size_t persistent_data_size; 108 109 /** Driver transient data. 110 * 111 * The core initializes this value to 0 and does not read or modify it 112 * afterwards. The driver may store whatever it wants in this field. 113 */ 114 uintptr_t transient_data; 115 } psa_drv_se_context_t; 116 117 /** \brief A driver initialization function. 118 * 119 * \param[in,out] drv_context The driver context structure. 120 * \param[in,out] persistent_data A pointer to the persistent data 121 * that allows writing. 122 * \param location The location value for which this driver 123 * is registered. The driver will be invoked 124 * for all keys whose lifetime is in this 125 * location. 126 * 127 * \retval #PSA_SUCCESS 128 * The driver is operational. 129 * The core will update the persistent data in storage. 130 * \return 131 * Any other return value prevents the driver from being used in 132 * this session. 133 * The core will NOT update the persistent data in storage. 134 */ 135 typedef psa_status_t (*psa_drv_se_init_t)(psa_drv_se_context_t *drv_context, 136 void *persistent_data, 137 psa_key_location_t location); 138 139 #if defined(__DOXYGEN_ONLY__) || !defined(MBEDTLS_PSA_CRYPTO_SE_C) 140 /* Mbed Crypto with secure element support enabled defines this type in 141 * crypto_types.h because it is also visible to applications through an 142 * implementation-specific extension. 143 * For the PSA Cryptography specification, this type is only visible 144 * via crypto_se_driver.h. */ 145 /** An internal designation of a key slot between the core part of the 146 * PSA Crypto implementation and the driver. The meaning of this value 147 * is driver-dependent. */ 148 typedef uint64_t psa_key_slot_number_t; 149 #endif /* __DOXYGEN_ONLY__ || !MBEDTLS_PSA_CRYPTO_SE_C */ 150 151 /**@}*/ 152 153 /** \defgroup se_mac Secure Element Message Authentication Codes 154 * Generation and authentication of Message Authentication Codes (MACs) using 155 * a secure element can be done either as a single function call (via the 156 * `psa_drv_se_mac_generate_t` or `psa_drv_se_mac_verify_t` functions), or in 157 * parts using the following sequence: 158 * - `psa_drv_se_mac_setup_t` 159 * - `psa_drv_se_mac_update_t` 160 * - `psa_drv_se_mac_update_t` 161 * - ... 162 * - `psa_drv_se_mac_finish_t` or `psa_drv_se_mac_finish_verify_t` 163 * 164 * If a previously started secure element MAC operation needs to be terminated, 165 * it should be done so by the `psa_drv_se_mac_abort_t`. Failure to do so may 166 * result in allocated resources not being freed or in other undefined 167 * behavior. 168 */ 169 /**@{*/ 170 /** \brief A function that starts a secure element MAC operation for a PSA 171 * Crypto Driver implementation 172 * 173 * \param[in,out] drv_context The driver context structure. 174 * \param[in,out] op_context A structure that will contain the 175 * hardware-specific MAC context 176 * \param[in] key_slot The slot of the key to be used for the 177 * operation 178 * \param[in] algorithm The algorithm to be used to underly the MAC 179 * operation 180 * 181 * \retval #PSA_SUCCESS 182 * Success. 183 */ 184 typedef psa_status_t (*psa_drv_se_mac_setup_t)(psa_drv_se_context_t *drv_context, 185 void *op_context, 186 psa_key_slot_number_t key_slot, 187 psa_algorithm_t algorithm); 188 189 /** \brief A function that continues a previously started secure element MAC 190 * operation 191 * 192 * \param[in,out] op_context A hardware-specific structure for the 193 * previously-established MAC operation to be 194 * updated 195 * \param[in] p_input A buffer containing the message to be appended 196 * to the MAC operation 197 * \param[in] input_length The size in bytes of the input message buffer 198 */ 199 typedef psa_status_t (*psa_drv_se_mac_update_t)(void *op_context, 200 const uint8_t *p_input, 201 size_t input_length); 202 203 /** \brief a function that completes a previously started secure element MAC 204 * operation by returning the resulting MAC. 205 * 206 * \param[in,out] op_context A hardware-specific structure for the 207 * previously started MAC operation to be 208 * finished 209 * \param[out] p_mac A buffer where the generated MAC will be 210 * placed 211 * \param[in] mac_size The size in bytes of the buffer that has been 212 * allocated for the `output` buffer 213 * \param[out] p_mac_length After completion, will contain the number of 214 * bytes placed in the `p_mac` buffer 215 * 216 * \retval #PSA_SUCCESS 217 * Success. 218 */ 219 typedef psa_status_t (*psa_drv_se_mac_finish_t)(void *op_context, 220 uint8_t *p_mac, 221 size_t mac_size, 222 size_t *p_mac_length); 223 224 /** \brief A function that completes a previously started secure element MAC 225 * operation by comparing the resulting MAC against a provided value 226 * 227 * \param[in,out] op_context A hardware-specific structure for the previously 228 * started MAC operation to be fiinished 229 * \param[in] p_mac The MAC value against which the resulting MAC 230 * will be compared against 231 * \param[in] mac_length The size in bytes of the value stored in `p_mac` 232 * 233 * \retval #PSA_SUCCESS 234 * The operation completed successfully and the MACs matched each 235 * other 236 * \retval #PSA_ERROR_INVALID_SIGNATURE 237 * The operation completed successfully, but the calculated MAC did 238 * not match the provided MAC 239 */ 240 typedef psa_status_t (*psa_drv_se_mac_finish_verify_t)(void *op_context, 241 const uint8_t *p_mac, 242 size_t mac_length); 243 244 /** \brief A function that aborts a previous started secure element MAC 245 * operation 246 * 247 * \param[in,out] op_context A hardware-specific structure for the previously 248 * started MAC operation to be aborted 249 */ 250 typedef psa_status_t (*psa_drv_se_mac_abort_t)(void *op_context); 251 252 /** \brief A function that performs a secure element MAC operation in one 253 * command and returns the calculated MAC 254 * 255 * \param[in,out] drv_context The driver context structure. 256 * \param[in] p_input A buffer containing the message to be MACed 257 * \param[in] input_length The size in bytes of `p_input` 258 * \param[in] key_slot The slot of the key to be used 259 * \param[in] alg The algorithm to be used to underlie the MAC 260 * operation 261 * \param[out] p_mac A buffer where the generated MAC will be 262 * placed 263 * \param[in] mac_size The size in bytes of the `p_mac` buffer 264 * \param[out] p_mac_length After completion, will contain the number of 265 * bytes placed in the `output` buffer 266 * 267 * \retval #PSA_SUCCESS 268 * Success. 269 */ 270 typedef psa_status_t (*psa_drv_se_mac_generate_t)(psa_drv_se_context_t *drv_context, 271 const uint8_t *p_input, 272 size_t input_length, 273 psa_key_slot_number_t key_slot, 274 psa_algorithm_t alg, 275 uint8_t *p_mac, 276 size_t mac_size, 277 size_t *p_mac_length); 278 279 /** \brief A function that performs a secure element MAC operation in one 280 * command and compares the resulting MAC against a provided value 281 * 282 * \param[in,out] drv_context The driver context structure. 283 * \param[in] p_input A buffer containing the message to be MACed 284 * \param[in] input_length The size in bytes of `input` 285 * \param[in] key_slot The slot of the key to be used 286 * \param[in] alg The algorithm to be used to underlie the MAC 287 * operation 288 * \param[in] p_mac The MAC value against which the resulting MAC will 289 * be compared against 290 * \param[in] mac_length The size in bytes of `mac` 291 * 292 * \retval #PSA_SUCCESS 293 * The operation completed successfully and the MACs matched each 294 * other 295 * \retval #PSA_ERROR_INVALID_SIGNATURE 296 * The operation completed successfully, but the calculated MAC did 297 * not match the provided MAC 298 */ 299 typedef psa_status_t (*psa_drv_se_mac_verify_t)(psa_drv_se_context_t *drv_context, 300 const uint8_t *p_input, 301 size_t input_length, 302 psa_key_slot_number_t key_slot, 303 psa_algorithm_t alg, 304 const uint8_t *p_mac, 305 size_t mac_length); 306 307 /** \brief A struct containing all of the function pointers needed to 308 * perform secure element MAC operations 309 * 310 * PSA Crypto API implementations should populate the table as appropriate 311 * upon startup. 312 * 313 * If one of the functions is not implemented (such as 314 * `psa_drv_se_mac_generate_t`), it should be set to NULL. 315 * 316 * Driver implementers should ensure that they implement all of the functions 317 * that make sense for their hardware, and that they provide a full solution 318 * (for example, if they support `p_setup`, they should also support 319 * `p_update` and at least one of `p_finish` or `p_finish_verify`). 320 * 321 */ 322 typedef struct { 323 /**The size in bytes of the hardware-specific secure element MAC context 324 * structure 325 */ 326 size_t context_size; 327 /** Function that performs a MAC setup operation 328 */ 329 psa_drv_se_mac_setup_t p_setup; 330 /** Function that performs a MAC update operation 331 */ 332 psa_drv_se_mac_update_t p_update; 333 /** Function that completes a MAC operation 334 */ 335 psa_drv_se_mac_finish_t p_finish; 336 /** Function that completes a MAC operation with a verify check 337 */ 338 psa_drv_se_mac_finish_verify_t p_finish_verify; 339 /** Function that aborts a previoustly started MAC operation 340 */ 341 psa_drv_se_mac_abort_t p_abort; 342 /** Function that performs a MAC operation in one call 343 */ 344 psa_drv_se_mac_generate_t p_mac; 345 /** Function that performs a MAC and verify operation in one call 346 */ 347 psa_drv_se_mac_verify_t p_mac_verify; 348 } psa_drv_se_mac_t; 349 /**@}*/ 350 351 /** \defgroup se_cipher Secure Element Symmetric Ciphers 352 * 353 * Encryption and Decryption using secure element keys in block modes other 354 * than ECB must be done in multiple parts, using the following flow: 355 * - `psa_drv_se_cipher_setup_t` 356 * - `psa_drv_se_cipher_set_iv_t` (optional depending upon block mode) 357 * - `psa_drv_se_cipher_update_t` 358 * - `psa_drv_se_cipher_update_t` 359 * - ... 360 * - `psa_drv_se_cipher_finish_t` 361 * 362 * If a previously started secure element Cipher operation needs to be 363 * terminated, it should be done so by the `psa_drv_se_cipher_abort_t`. Failure 364 * to do so may result in allocated resources not being freed or in other 365 * undefined behavior. 366 * 367 * In situations where a PSA Cryptographic API implementation is using a block 368 * mode not-supported by the underlying hardware or driver, it can construct 369 * the block mode itself, while calling the `psa_drv_se_cipher_ecb_t` function 370 * for the cipher operations. 371 */ 372 /**@{*/ 373 374 /** \brief A function that provides the cipher setup function for a 375 * secure element driver 376 * 377 * \param[in,out] drv_context The driver context structure. 378 * \param[in,out] op_context A structure that will contain the 379 * hardware-specific cipher context. 380 * \param[in] key_slot The slot of the key to be used for the 381 * operation 382 * \param[in] algorithm The algorithm to be used in the cipher 383 * operation 384 * \param[in] direction Indicates whether the operation is an encrypt 385 * or decrypt 386 * 387 * \retval #PSA_SUCCESS 388 * \retval #PSA_ERROR_NOT_SUPPORTED 389 */ 390 typedef psa_status_t (*psa_drv_se_cipher_setup_t)(psa_drv_se_context_t *drv_context, 391 void *op_context, 392 psa_key_slot_number_t key_slot, 393 psa_algorithm_t algorithm, 394 psa_encrypt_or_decrypt_t direction); 395 396 /** \brief A function that sets the initialization vector (if 397 * necessary) for an secure element cipher operation 398 * 399 * Rationale: The `psa_se_cipher_*` operation in the PSA Cryptographic API has 400 * two IV functions: one to set the IV, and one to generate it internally. The 401 * generate function is not necessary for the drivers to implement as the PSA 402 * Crypto implementation can do the generation using its RNG features. 403 * 404 * \param[in,out] op_context A structure that contains the previously set up 405 * hardware-specific cipher context 406 * \param[in] p_iv A buffer containing the initialization vector 407 * \param[in] iv_length The size (in bytes) of the `p_iv` buffer 408 * 409 * \retval #PSA_SUCCESS 410 */ 411 typedef psa_status_t (*psa_drv_se_cipher_set_iv_t)(void *op_context, 412 const uint8_t *p_iv, 413 size_t iv_length); 414 415 /** \brief A function that continues a previously started secure element cipher 416 * operation 417 * 418 * \param[in,out] op_context A hardware-specific structure for the 419 * previously started cipher operation 420 * \param[in] p_input A buffer containing the data to be 421 * encrypted/decrypted 422 * \param[in] input_size The size in bytes of the buffer pointed to 423 * by `p_input` 424 * \param[out] p_output The caller-allocated buffer where the 425 * output will be placed 426 * \param[in] output_size The allocated size in bytes of the 427 * `p_output` buffer 428 * \param[out] p_output_length After completion, will contain the number 429 * of bytes placed in the `p_output` buffer 430 * 431 * \retval #PSA_SUCCESS 432 */ 433 typedef psa_status_t (*psa_drv_se_cipher_update_t)(void *op_context, 434 const uint8_t *p_input, 435 size_t input_size, 436 uint8_t *p_output, 437 size_t output_size, 438 size_t *p_output_length); 439 440 /** \brief A function that completes a previously started secure element cipher 441 * operation 442 * 443 * \param[in,out] op_context A hardware-specific structure for the 444 * previously started cipher operation 445 * \param[out] p_output The caller-allocated buffer where the output 446 * will be placed 447 * \param[in] output_size The allocated size in bytes of the `p_output` 448 * buffer 449 * \param[out] p_output_length After completion, will contain the number of 450 * bytes placed in the `p_output` buffer 451 * 452 * \retval #PSA_SUCCESS 453 */ 454 typedef psa_status_t (*psa_drv_se_cipher_finish_t)(void *op_context, 455 uint8_t *p_output, 456 size_t output_size, 457 size_t *p_output_length); 458 459 /** \brief A function that aborts a previously started secure element cipher 460 * operation 461 * 462 * \param[in,out] op_context A hardware-specific structure for the 463 * previously started cipher operation 464 */ 465 typedef psa_status_t (*psa_drv_se_cipher_abort_t)(void *op_context); 466 467 /** \brief A function that performs the ECB block mode for secure element 468 * cipher operations 469 * 470 * Note: this function should only be used with implementations that do not 471 * provide a needed higher-level operation. 472 * 473 * \param[in,out] drv_context The driver context structure. 474 * \param[in] key_slot The slot of the key to be used for the operation 475 * \param[in] algorithm The algorithm to be used in the cipher operation 476 * \param[in] direction Indicates whether the operation is an encrypt or 477 * decrypt 478 * \param[in] p_input A buffer containing the data to be 479 * encrypted/decrypted 480 * \param[in] input_size The size in bytes of the buffer pointed to by 481 * `p_input` 482 * \param[out] p_output The caller-allocated buffer where the output 483 * will be placed 484 * \param[in] output_size The allocated size in bytes of the `p_output` 485 * buffer 486 * 487 * \retval #PSA_SUCCESS 488 * \retval #PSA_ERROR_NOT_SUPPORTED 489 */ 490 typedef psa_status_t (*psa_drv_se_cipher_ecb_t)(psa_drv_se_context_t *drv_context, 491 psa_key_slot_number_t key_slot, 492 psa_algorithm_t algorithm, 493 psa_encrypt_or_decrypt_t direction, 494 const uint8_t *p_input, 495 size_t input_size, 496 uint8_t *p_output, 497 size_t output_size); 498 499 /** 500 * \brief A struct containing all of the function pointers needed to implement 501 * cipher operations using secure elements. 502 * 503 * PSA Crypto API implementations should populate instances of the table as 504 * appropriate upon startup or at build time. 505 * 506 * If one of the functions is not implemented (such as 507 * `psa_drv_se_cipher_ecb_t`), it should be set to NULL. 508 */ 509 typedef struct { 510 /** The size in bytes of the hardware-specific secure element cipher 511 * context structure 512 */ 513 size_t context_size; 514 /** Function that performs a cipher setup operation */ 515 psa_drv_se_cipher_setup_t p_setup; 516 /** Function that sets a cipher IV (if necessary) */ 517 psa_drv_se_cipher_set_iv_t p_set_iv; 518 /** Function that performs a cipher update operation */ 519 psa_drv_se_cipher_update_t p_update; 520 /** Function that completes a cipher operation */ 521 psa_drv_se_cipher_finish_t p_finish; 522 /** Function that aborts a cipher operation */ 523 psa_drv_se_cipher_abort_t p_abort; 524 /** Function that performs ECB mode for a cipher operation 525 * (Danger: ECB mode should not be used directly by clients of the PSA 526 * Crypto Client API) 527 */ 528 psa_drv_se_cipher_ecb_t p_ecb; 529 } psa_drv_se_cipher_t; 530 531 /**@}*/ 532 533 /** \defgroup se_asymmetric Secure Element Asymmetric Cryptography 534 * 535 * Since the amount of data that can (or should) be encrypted or signed using 536 * asymmetric keys is limited by the key size, asymmetric key operations using 537 * keys in a secure element must be done in single function calls. 538 */ 539 /**@{*/ 540 541 /** 542 * \brief A function that signs a hash or short message with a private key in 543 * a secure element 544 * 545 * \param[in,out] drv_context The driver context structure. 546 * \param[in] key_slot Key slot of an asymmetric key pair 547 * \param[in] alg A signature algorithm that is compatible 548 * with the type of `key` 549 * \param[in] p_hash The hash to sign 550 * \param[in] hash_length Size of the `p_hash` buffer in bytes 551 * \param[out] p_signature Buffer where the signature is to be written 552 * \param[in] signature_size Size of the `p_signature` buffer in bytes 553 * \param[out] p_signature_length On success, the number of bytes 554 * that make up the returned signature value 555 * 556 * \retval #PSA_SUCCESS 557 */ 558 typedef psa_status_t (*psa_drv_se_asymmetric_sign_t)(psa_drv_se_context_t *drv_context, 559 psa_key_slot_number_t key_slot, 560 psa_algorithm_t alg, 561 const uint8_t *p_hash, 562 size_t hash_length, 563 uint8_t *p_signature, 564 size_t signature_size, 565 size_t *p_signature_length); 566 567 /** 568 * \brief A function that verifies the signature a hash or short message using 569 * an asymmetric public key in a secure element 570 * 571 * \param[in,out] drv_context The driver context structure. 572 * \param[in] key_slot Key slot of a public key or an asymmetric key 573 * pair 574 * \param[in] alg A signature algorithm that is compatible with 575 * the type of `key` 576 * \param[in] p_hash The hash whose signature is to be verified 577 * \param[in] hash_length Size of the `p_hash` buffer in bytes 578 * \param[in] p_signature Buffer containing the signature to verify 579 * \param[in] signature_length Size of the `p_signature` buffer in bytes 580 * 581 * \retval #PSA_SUCCESS 582 * The signature is valid. 583 */ 584 typedef psa_status_t (*psa_drv_se_asymmetric_verify_t)(psa_drv_se_context_t *drv_context, 585 psa_key_slot_number_t key_slot, 586 psa_algorithm_t alg, 587 const uint8_t *p_hash, 588 size_t hash_length, 589 const uint8_t *p_signature, 590 size_t signature_length); 591 592 /** 593 * \brief A function that encrypts a short message with an asymmetric public 594 * key in a secure element 595 * 596 * \param[in,out] drv_context The driver context structure. 597 * \param[in] key_slot Key slot of a public key or an asymmetric key 598 * pair 599 * \param[in] alg An asymmetric encryption algorithm that is 600 * compatible with the type of `key` 601 * \param[in] p_input The message to encrypt 602 * \param[in] input_length Size of the `p_input` buffer in bytes 603 * \param[in] p_salt A salt or label, if supported by the 604 * encryption algorithm 605 * If the algorithm does not support a 606 * salt, pass `NULL`. 607 * If the algorithm supports an optional 608 * salt and you do not want to pass a salt, 609 * pass `NULL`. 610 * For #PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is 611 * supported. 612 * \param[in] salt_length Size of the `p_salt` buffer in bytes 613 * If `p_salt` is `NULL`, pass 0. 614 * \param[out] p_output Buffer where the encrypted message is to 615 * be written 616 * \param[in] output_size Size of the `p_output` buffer in bytes 617 * \param[out] p_output_length On success, the number of bytes that make up 618 * the returned output 619 * 620 * \retval #PSA_SUCCESS 621 */ 622 typedef psa_status_t (*psa_drv_se_asymmetric_encrypt_t)(psa_drv_se_context_t *drv_context, 623 psa_key_slot_number_t key_slot, 624 psa_algorithm_t alg, 625 const uint8_t *p_input, 626 size_t input_length, 627 const uint8_t *p_salt, 628 size_t salt_length, 629 uint8_t *p_output, 630 size_t output_size, 631 size_t *p_output_length); 632 633 /** 634 * \brief A function that decrypts a short message with an asymmetric private 635 * key in a secure element. 636 * 637 * \param[in,out] drv_context The driver context structure. 638 * \param[in] key_slot Key slot of an asymmetric key pair 639 * \param[in] alg An asymmetric encryption algorithm that is 640 * compatible with the type of `key` 641 * \param[in] p_input The message to decrypt 642 * \param[in] input_length Size of the `p_input` buffer in bytes 643 * \param[in] p_salt A salt or label, if supported by the 644 * encryption algorithm 645 * If the algorithm does not support a 646 * salt, pass `NULL`. 647 * If the algorithm supports an optional 648 * salt and you do not want to pass a salt, 649 * pass `NULL`. 650 * For #PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is 651 * supported. 652 * \param[in] salt_length Size of the `p_salt` buffer in bytes 653 * If `p_salt` is `NULL`, pass 0. 654 * \param[out] p_output Buffer where the decrypted message is to 655 * be written 656 * \param[in] output_size Size of the `p_output` buffer in bytes 657 * \param[out] p_output_length On success, the number of bytes 658 * that make up the returned output 659 * 660 * \retval #PSA_SUCCESS 661 */ 662 typedef psa_status_t (*psa_drv_se_asymmetric_decrypt_t)(psa_drv_se_context_t *drv_context, 663 psa_key_slot_number_t key_slot, 664 psa_algorithm_t alg, 665 const uint8_t *p_input, 666 size_t input_length, 667 const uint8_t *p_salt, 668 size_t salt_length, 669 uint8_t *p_output, 670 size_t output_size, 671 size_t *p_output_length); 672 673 /** 674 * \brief A struct containing all of the function pointers needed to implement 675 * asymmetric cryptographic operations using secure elements. 676 * 677 * PSA Crypto API implementations should populate instances of the table as 678 * appropriate upon startup or at build time. 679 * 680 * If one of the functions is not implemented, it should be set to NULL. 681 */ 682 typedef struct { 683 /** Function that performs an asymmetric sign operation */ 684 psa_drv_se_asymmetric_sign_t p_sign; 685 /** Function that performs an asymmetric verify operation */ 686 psa_drv_se_asymmetric_verify_t p_verify; 687 /** Function that performs an asymmetric encrypt operation */ 688 psa_drv_se_asymmetric_encrypt_t p_encrypt; 689 /** Function that performs an asymmetric decrypt operation */ 690 psa_drv_se_asymmetric_decrypt_t p_decrypt; 691 } psa_drv_se_asymmetric_t; 692 693 /**@}*/ 694 695 /** \defgroup se_aead Secure Element Authenticated Encryption with Additional Data 696 * Authenticated Encryption with Additional Data (AEAD) operations with secure 697 * elements must be done in one function call. While this creates a burden for 698 * implementers as there must be sufficient space in memory for the entire 699 * message, it prevents decrypted data from being made available before the 700 * authentication operation is complete and the data is known to be authentic. 701 */ 702 /**@{*/ 703 704 /** \brief A function that performs a secure element authenticated encryption 705 * operation 706 * 707 * \param[in,out] drv_context The driver context structure. 708 * \param[in] key_slot Slot containing the key to use. 709 * \param[in] algorithm The AEAD algorithm to compute 710 * (\c PSA_ALG_XXX value such that 711 * #PSA_ALG_IS_AEAD(`alg`) is true) 712 * \param[in] p_nonce Nonce or IV to use 713 * \param[in] nonce_length Size of the `p_nonce` buffer in bytes 714 * \param[in] p_additional_data Additional data that will be 715 * authenticated but not encrypted 716 * \param[in] additional_data_length Size of `p_additional_data` in bytes 717 * \param[in] p_plaintext Data that will be authenticated and 718 * encrypted 719 * \param[in] plaintext_length Size of `p_plaintext` in bytes 720 * \param[out] p_ciphertext Output buffer for the authenticated and 721 * encrypted data. The additional data is 722 * not part of this output. For algorithms 723 * where the encrypted data and the 724 * authentication tag are defined as 725 * separate outputs, the authentication 726 * tag is appended to the encrypted data. 727 * \param[in] ciphertext_size Size of the `p_ciphertext` buffer in 728 * bytes 729 * \param[out] p_ciphertext_length On success, the size of the output in 730 * the `p_ciphertext` buffer 731 * 732 * \retval #PSA_SUCCESS 733 * Success. 734 */ 735 typedef psa_status_t (*psa_drv_se_aead_encrypt_t)(psa_drv_se_context_t *drv_context, 736 psa_key_slot_number_t key_slot, 737 psa_algorithm_t algorithm, 738 const uint8_t *p_nonce, 739 size_t nonce_length, 740 const uint8_t *p_additional_data, 741 size_t additional_data_length, 742 const uint8_t *p_plaintext, 743 size_t plaintext_length, 744 uint8_t *p_ciphertext, 745 size_t ciphertext_size, 746 size_t *p_ciphertext_length); 747 748 /** A function that peforms a secure element authenticated decryption operation 749 * 750 * \param[in,out] drv_context The driver context structure. 751 * \param[in] key_slot Slot containing the key to use 752 * \param[in] algorithm The AEAD algorithm to compute 753 * (\c PSA_ALG_XXX value such that 754 * #PSA_ALG_IS_AEAD(`alg`) is true) 755 * \param[in] p_nonce Nonce or IV to use 756 * \param[in] nonce_length Size of the `p_nonce` buffer in bytes 757 * \param[in] p_additional_data Additional data that has been 758 * authenticated but not encrypted 759 * \param[in] additional_data_length Size of `p_additional_data` in bytes 760 * \param[in] p_ciphertext Data that has been authenticated and 761 * encrypted. 762 * For algorithms where the encrypted data 763 * and the authentication tag are defined 764 * as separate inputs, the buffer must 765 * contain the encrypted data followed by 766 * the authentication tag. 767 * \param[in] ciphertext_length Size of `p_ciphertext` in bytes 768 * \param[out] p_plaintext Output buffer for the decrypted data 769 * \param[in] plaintext_size Size of the `p_plaintext` buffer in 770 * bytes 771 * \param[out] p_plaintext_length On success, the size of the output in 772 * the `p_plaintext` buffer 773 * 774 * \retval #PSA_SUCCESS 775 * Success. 776 */ 777 typedef psa_status_t (*psa_drv_se_aead_decrypt_t)(psa_drv_se_context_t *drv_context, 778 psa_key_slot_number_t key_slot, 779 psa_algorithm_t algorithm, 780 const uint8_t *p_nonce, 781 size_t nonce_length, 782 const uint8_t *p_additional_data, 783 size_t additional_data_length, 784 const uint8_t *p_ciphertext, 785 size_t ciphertext_length, 786 uint8_t *p_plaintext, 787 size_t plaintext_size, 788 size_t *p_plaintext_length); 789 790 /** 791 * \brief A struct containing all of the function pointers needed to implement 792 * secure element Authenticated Encryption with Additional Data operations 793 * 794 * PSA Crypto API implementations should populate instances of the table as 795 * appropriate upon startup. 796 * 797 * If one of the functions is not implemented, it should be set to NULL. 798 */ 799 typedef struct { 800 /** Function that performs the AEAD encrypt operation */ 801 psa_drv_se_aead_encrypt_t p_encrypt; 802 /** Function that performs the AEAD decrypt operation */ 803 psa_drv_se_aead_decrypt_t p_decrypt; 804 } psa_drv_se_aead_t; 805 /**@}*/ 806 807 /** \defgroup se_key_management Secure Element Key Management 808 * Currently, key management is limited to importing keys in the clear, 809 * destroying keys, and exporting keys in the clear. 810 * Whether a key may be exported is determined by the key policies in place 811 * on the key slot. 812 */ 813 /**@{*/ 814 815 /** An enumeration indicating how a key is created. 816 */ 817 typedef enum 818 { 819 PSA_KEY_CREATION_IMPORT, /**< During psa_import_key() */ 820 PSA_KEY_CREATION_GENERATE, /**< During psa_generate_key() */ 821 PSA_KEY_CREATION_DERIVE, /**< During psa_key_derivation_output_key() */ 822 PSA_KEY_CREATION_COPY, /**< During psa_copy_key() */ 823 824 #ifndef __DOXYGEN_ONLY__ 825 /** A key is being registered with mbedtls_psa_register_se_key(). 826 * 827 * The core only passes this value to 828 * psa_drv_se_key_management_t::p_validate_slot_number, not to 829 * psa_drv_se_key_management_t::p_allocate. The call to 830 * `p_validate_slot_number` is not followed by any other call to the 831 * driver: the key is considered successfully registered if the call to 832 * `p_validate_slot_number` succeeds, or if `p_validate_slot_number` is 833 * null. 834 * 835 * With this creation method, the driver must return #PSA_SUCCESS if 836 * the given attributes are compatible with the existing key in the slot, 837 * and #PSA_ERROR_DOES_NOT_EXIST if the driver can determine that there 838 * is no key with the specified slot number. 839 * 840 * This is an Mbed Crypto extension. 841 */ 842 PSA_KEY_CREATION_REGISTER, 843 #endif 844 } psa_key_creation_method_t; 845 846 /** \brief A function that allocates a slot for a key. 847 * 848 * To create a key in a specific slot in a secure element, the core 849 * first calls this function to determine a valid slot number, 850 * then calls a function to create the key material in that slot. 851 * In nominal conditions (that is, if no error occurs), 852 * the effect of a call to a key creation function in the PSA Cryptography 853 * API with a lifetime that places the key in a secure element is the 854 * following: 855 * -# The core calls psa_drv_se_key_management_t::p_allocate 856 * (or in some implementations 857 * psa_drv_se_key_management_t::p_validate_slot_number). The driver 858 * selects (or validates) a suitable slot number given the key attributes 859 * and the state of the secure element. 860 * -# The core calls a key creation function in the driver. 861 * 862 * The key creation functions in the PSA Cryptography API are: 863 * - psa_import_key(), which causes 864 * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_IMPORT 865 * then a call to psa_drv_se_key_management_t::p_import. 866 * - psa_generate_key(), which causes 867 * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_GENERATE 868 * then a call to psa_drv_se_key_management_t::p_import. 869 * - psa_key_derivation_output_key(), which causes 870 * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_DERIVE 871 * then a call to psa_drv_se_key_derivation_t::p_derive. 872 * - psa_copy_key(), which causes 873 * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_COPY 874 * then a call to psa_drv_se_key_management_t::p_export. 875 * 876 * In case of errors, other behaviors are possible. 877 * - If the PSA Cryptography subsystem dies after the first step, 878 * for example because the device has lost power abruptly, 879 * the second step may never happen, or may happen after a reset 880 * and re-initialization. Alternatively, after a reset and 881 * re-initialization, the core may call 882 * psa_drv_se_key_management_t::p_destroy on the slot number that 883 * was allocated (or validated) instead of calling a key creation function. 884 * - If an error occurs, the core may call 885 * psa_drv_se_key_management_t::p_destroy on the slot number that 886 * was allocated (or validated) instead of calling a key creation function. 887 * 888 * Errors and system resets also have an impact on the driver's persistent 889 * data. If a reset happens before the overall key creation process is 890 * completed (before or after the second step above), it is unspecified 891 * whether the persistent data after the reset is identical to what it 892 * was before or after the call to `p_allocate` (or `p_validate_slot_number`). 893 * 894 * \param[in,out] drv_context The driver context structure. 895 * \param[in,out] persistent_data A pointer to the persistent data 896 * that allows writing. 897 * \param[in] attributes Attributes of the key. 898 * \param method The way in which the key is being created. 899 * \param[out] key_slot Slot where the key will be stored. 900 * This must be a valid slot for a key of the 901 * chosen type. It must be unoccupied. 902 * 903 * \retval #PSA_SUCCESS 904 * Success. 905 * The core will record \c *key_slot as the key slot where the key 906 * is stored and will update the persistent data in storage. 907 * \retval #PSA_ERROR_NOT_SUPPORTED 908 * \retval #PSA_ERROR_INSUFFICIENT_STORAGE 909 */ 910 typedef psa_status_t (*psa_drv_se_allocate_key_t)( 911 psa_drv_se_context_t *drv_context, 912 void *persistent_data, 913 const psa_key_attributes_t *attributes, 914 psa_key_creation_method_t method, 915 psa_key_slot_number_t *key_slot); 916 917 /** \brief A function that determines whether a slot number is valid 918 * for a key. 919 * 920 * To create a key in a specific slot in a secure element, the core 921 * first calls this function to validate the choice of slot number, 922 * then calls a function to create the key material in that slot. 923 * See the documentation of #psa_drv_se_allocate_key_t for more details. 924 * 925 * As of the PSA Cryptography API specification version 1.0, there is no way 926 * for applications to trigger a call to this function. However some 927 * implementations offer the capability to create or declare a key in 928 * a specific slot via implementation-specific means, generally for the 929 * sake of initial device provisioning or onboarding. Such a mechanism may 930 * be added to a future version of the PSA Cryptography API specification. 931 * 932 * This function may update the driver's persistent data through 933 * \p persistent_data. The core will save the updated persistent data at the 934 * end of the key creation process. See the description of 935 * ::psa_drv_se_allocate_key_t for more information. 936 * 937 * \param[in,out] drv_context The driver context structure. 938 * \param[in,out] persistent_data A pointer to the persistent data 939 * that allows writing. 940 * \param[in] attributes Attributes of the key. 941 * \param method The way in which the key is being created. 942 * \param[in] key_slot Slot where the key is to be stored. 943 * 944 * \retval #PSA_SUCCESS 945 * The given slot number is valid for a key with the given 946 * attributes. 947 * \retval #PSA_ERROR_INVALID_ARGUMENT 948 * The given slot number is not valid for a key with the 949 * given attributes. This includes the case where the slot 950 * number is not valid at all. 951 * \retval #PSA_ERROR_ALREADY_EXISTS 952 * There is already a key with the specified slot number. 953 * Drivers may choose to return this error from the key 954 * creation function instead. 955 */ 956 typedef psa_status_t (*psa_drv_se_validate_slot_number_t)( 957 psa_drv_se_context_t *drv_context, 958 void *persistent_data, 959 const psa_key_attributes_t *attributes, 960 psa_key_creation_method_t method, 961 psa_key_slot_number_t key_slot); 962 963 /** \brief A function that imports a key into a secure element in binary format 964 * 965 * This function can support any output from psa_export_key(). Refer to the 966 * documentation of psa_export_key() for the format for each key type. 967 * 968 * \param[in,out] drv_context The driver context structure. 969 * \param key_slot Slot where the key will be stored. 970 * This must be a valid slot for a key of the 971 * chosen type. It must be unoccupied. 972 * \param[in] attributes The key attributes, including the lifetime, 973 * the key type and the usage policy. 974 * Drivers should not access the key size stored 975 * in the attributes: it may not match the 976 * data passed in \p data. 977 * Drivers can call psa_get_key_lifetime(), 978 * psa_get_key_type(), 979 * psa_get_key_usage_flags() and 980 * psa_get_key_algorithm() to access this 981 * information. 982 * \param[in] data Buffer containing the key data. 983 * \param[in] data_length Size of the \p data buffer in bytes. 984 * \param[out] bits On success, the key size in bits. The driver 985 * must determine this value after parsing the 986 * key according to the key type. 987 * This value is not used if the function fails. 988 * 989 * \retval #PSA_SUCCESS 990 * Success. 991 */ 992 typedef psa_status_t (*psa_drv_se_import_key_t)( 993 psa_drv_se_context_t *drv_context, 994 psa_key_slot_number_t key_slot, 995 const psa_key_attributes_t *attributes, 996 const uint8_t *data, 997 size_t data_length, 998 size_t *bits); 999 1000 /** 1001 * \brief A function that destroys a secure element key and restore the slot to 1002 * its default state 1003 * 1004 * This function destroys the content of the key from a secure element. 1005 * Implementations shall make a best effort to ensure that any previous content 1006 * of the slot is unrecoverable. 1007 * 1008 * This function returns the specified slot to its default state. 1009 * 1010 * \param[in,out] drv_context The driver context structure. 1011 * \param[in,out] persistent_data A pointer to the persistent data 1012 * that allows writing. 1013 * \param key_slot The key slot to erase. 1014 * 1015 * \retval #PSA_SUCCESS 1016 * The slot's content, if any, has been erased. 1017 */ 1018 typedef psa_status_t (*psa_drv_se_destroy_key_t)( 1019 psa_drv_se_context_t *drv_context, 1020 void *persistent_data, 1021 psa_key_slot_number_t key_slot); 1022 1023 /** 1024 * \brief A function that exports a secure element key in binary format 1025 * 1026 * The output of this function can be passed to psa_import_key() to 1027 * create an equivalent object. 1028 * 1029 * If a key is created with `psa_import_key()` and then exported with 1030 * this function, it is not guaranteed that the resulting data is 1031 * identical: the implementation may choose a different representation 1032 * of the same key if the format permits it. 1033 * 1034 * This function should generate output in the same format that 1035 * `psa_export_key()` does. Refer to the 1036 * documentation of `psa_export_key()` for the format for each key type. 1037 * 1038 * \param[in,out] drv_context The driver context structure. 1039 * \param[in] key Slot whose content is to be exported. This must 1040 * be an occupied key slot. 1041 * \param[out] p_data Buffer where the key data is to be written. 1042 * \param[in] data_size Size of the `p_data` buffer in bytes. 1043 * \param[out] p_data_length On success, the number of bytes 1044 * that make up the key data. 1045 * 1046 * \retval #PSA_SUCCESS 1047 * \retval #PSA_ERROR_DOES_NOT_EXIST 1048 * \retval #PSA_ERROR_NOT_PERMITTED 1049 * \retval #PSA_ERROR_NOT_SUPPORTED 1050 * \retval #PSA_ERROR_COMMUNICATION_FAILURE 1051 * \retval #PSA_ERROR_HARDWARE_FAILURE 1052 * \retval #PSA_ERROR_CORRUPTION_DETECTED 1053 */ 1054 typedef psa_status_t (*psa_drv_se_export_key_t)(psa_drv_se_context_t *drv_context, 1055 psa_key_slot_number_t key, 1056 uint8_t *p_data, 1057 size_t data_size, 1058 size_t *p_data_length); 1059 1060 /** 1061 * \brief A function that generates a symmetric or asymmetric key on a secure 1062 * element 1063 * 1064 * If \p type is asymmetric (#PSA_KEY_TYPE_IS_ASYMMETRIC(\p type) = 1), 1065 * the driver may export the public key at the time of generation, 1066 * in the format documented for psa_export_public_key() by writing it 1067 * to the \p pubkey buffer. 1068 * This is optional, intended for secure elements that output the 1069 * public key at generation time and that cannot export the public key 1070 * later. Drivers that do not need this feature should leave 1071 * \p *pubkey_length set to 0 and should 1072 * implement the psa_drv_key_management_t::p_export_public function. 1073 * Some implementations do not support this feature, in which case 1074 * \p pubkey is \c NULL and \p pubkey_size is 0. 1075 * 1076 * \param[in,out] drv_context The driver context structure. 1077 * \param key_slot Slot where the key will be stored. 1078 * This must be a valid slot for a key of the 1079 * chosen type. It must be unoccupied. 1080 * \param[in] attributes The key attributes, including the lifetime, 1081 * the key type and size, and the usage policy. 1082 * Drivers can call psa_get_key_lifetime(), 1083 * psa_get_key_type(), psa_get_key_bits(), 1084 * psa_get_key_usage_flags() and 1085 * psa_get_key_algorithm() to access this 1086 * information. 1087 * \param[out] pubkey A buffer where the driver can write the 1088 * public key, when generating an asymmetric 1089 * key pair. 1090 * This is \c NULL when generating a symmetric 1091 * key or if the core does not support 1092 * exporting the public key at generation time. 1093 * \param pubkey_size The size of the `pubkey` buffer in bytes. 1094 * This is 0 when generating a symmetric 1095 * key or if the core does not support 1096 * exporting the public key at generation time. 1097 * \param[out] pubkey_length On entry, this is always 0. 1098 * On success, the number of bytes written to 1099 * \p pubkey. If this is 0 or unchanged on return, 1100 * the core will not read the \p pubkey buffer, 1101 * and will instead call the driver's 1102 * psa_drv_key_management_t::p_export_public 1103 * function to export the public key when needed. 1104 */ 1105 typedef psa_status_t (*psa_drv_se_generate_key_t)( 1106 psa_drv_se_context_t *drv_context, 1107 psa_key_slot_number_t key_slot, 1108 const psa_key_attributes_t *attributes, 1109 uint8_t *pubkey, size_t pubkey_size, size_t *pubkey_length); 1110 1111 /** 1112 * \brief A struct containing all of the function pointers needed to for secure 1113 * element key management 1114 * 1115 * PSA Crypto API implementations should populate instances of the table as 1116 * appropriate upon startup or at build time. 1117 * 1118 * If one of the functions is not implemented, it should be set to NULL. 1119 */ 1120 typedef struct { 1121 /** Function that allocates a slot for a key. */ 1122 psa_drv_se_allocate_key_t p_allocate; 1123 /** Function that checks the validity of a slot for a key. */ 1124 psa_drv_se_validate_slot_number_t p_validate_slot_number; 1125 /** Function that performs a key import operation */ 1126 psa_drv_se_import_key_t p_import; 1127 /** Function that performs a generation */ 1128 psa_drv_se_generate_key_t p_generate; 1129 /** Function that performs a key destroy operation */ 1130 psa_drv_se_destroy_key_t p_destroy; 1131 /** Function that performs a key export operation */ 1132 psa_drv_se_export_key_t p_export; 1133 /** Function that performs a public key export operation */ 1134 psa_drv_se_export_key_t p_export_public; 1135 } psa_drv_se_key_management_t; 1136 1137 /**@}*/ 1138 1139 /** \defgroup driver_derivation Secure Element Key Derivation and Agreement 1140 * Key derivation is the process of generating new key material using an 1141 * existing key and additional parameters, iterating through a basic 1142 * cryptographic function, such as a hash. 1143 * Key agreement is a part of cryptographic protocols that allows two parties 1144 * to agree on the same key value, but starting from different original key 1145 * material. 1146 * The flows are similar, and the PSA Crypto Driver Model uses the same functions 1147 * for both of the flows. 1148 * 1149 * There are two different final functions for the flows, 1150 * `psa_drv_se_key_derivation_derive` and `psa_drv_se_key_derivation_export`. 1151 * `psa_drv_se_key_derivation_derive` is used when the key material should be 1152 * placed in a slot on the hardware and not exposed to the caller. 1153 * `psa_drv_se_key_derivation_export` is used when the key material should be 1154 * returned to the PSA Cryptographic API implementation. 1155 * 1156 * Different key derivation algorithms require a different number of inputs. 1157 * Instead of having an API that takes as input variable length arrays, which 1158 * can be problemmatic to manage on embedded platforms, the inputs are passed 1159 * to the driver via a function, `psa_drv_se_key_derivation_collateral`, that 1160 * is called multiple times with different `collateral_id`s. Thus, for a key 1161 * derivation algorithm that required 3 paramter inputs, the flow would look 1162 * something like: 1163 * ~~~~~~~~~~~~~{.c} 1164 * psa_drv_se_key_derivation_setup(kdf_algorithm, source_key, dest_key_size_bytes); 1165 * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_0, 1166 * p_collateral_0, 1167 * collateral_0_size); 1168 * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_1, 1169 * p_collateral_1, 1170 * collateral_1_size); 1171 * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_2, 1172 * p_collateral_2, 1173 * collateral_2_size); 1174 * psa_drv_se_key_derivation_derive(); 1175 * ~~~~~~~~~~~~~ 1176 * 1177 * key agreement example: 1178 * ~~~~~~~~~~~~~{.c} 1179 * psa_drv_se_key_derivation_setup(alg, source_key. dest_key_size_bytes); 1180 * psa_drv_se_key_derivation_collateral(DHE_PUBKEY, p_pubkey, pubkey_size); 1181 * psa_drv_se_key_derivation_export(p_session_key, 1182 * session_key_size, 1183 * &session_key_length); 1184 * ~~~~~~~~~~~~~ 1185 */ 1186 /**@{*/ 1187 1188 /** \brief A function that Sets up a secure element key derivation operation by 1189 * specifying the algorithm and the source key sot 1190 * 1191 * \param[in,out] drv_context The driver context structure. 1192 * \param[in,out] op_context A hardware-specific structure containing any 1193 * context information for the implementation 1194 * \param[in] kdf_alg The algorithm to be used for the key derivation 1195 * \param[in] source_key The key to be used as the source material for 1196 * the key derivation 1197 * 1198 * \retval #PSA_SUCCESS 1199 */ 1200 typedef psa_status_t (*psa_drv_se_key_derivation_setup_t)(psa_drv_se_context_t *drv_context, 1201 void *op_context, 1202 psa_algorithm_t kdf_alg, 1203 psa_key_slot_number_t source_key); 1204 1205 /** \brief A function that provides collateral (parameters) needed for a secure 1206 * element key derivation or key agreement operation 1207 * 1208 * Since many key derivation algorithms require multiple parameters, it is 1209 * expeced that this function may be called multiple times for the same 1210 * operation, each with a different algorithm-specific `collateral_id` 1211 * 1212 * \param[in,out] op_context A hardware-specific structure containing any 1213 * context information for the implementation 1214 * \param[in] collateral_id An ID for the collateral being provided 1215 * \param[in] p_collateral A buffer containing the collateral data 1216 * \param[in] collateral_size The size in bytes of the collateral 1217 * 1218 * \retval #PSA_SUCCESS 1219 */ 1220 typedef psa_status_t (*psa_drv_se_key_derivation_collateral_t)(void *op_context, 1221 uint32_t collateral_id, 1222 const uint8_t *p_collateral, 1223 size_t collateral_size); 1224 1225 /** \brief A function that performs the final secure element key derivation 1226 * step and place the generated key material in a slot 1227 * 1228 * \param[in,out] op_context A hardware-specific structure containing any 1229 * context information for the implementation 1230 * \param[in] dest_key The slot where the generated key material 1231 * should be placed 1232 * 1233 * \retval #PSA_SUCCESS 1234 */ 1235 typedef psa_status_t (*psa_drv_se_key_derivation_derive_t)(void *op_context, 1236 psa_key_slot_number_t dest_key); 1237 1238 /** \brief A function that performs the final step of a secure element key 1239 * agreement and place the generated key material in a buffer 1240 * 1241 * \param[out] p_output Buffer in which to place the generated key 1242 * material 1243 * \param[in] output_size The size in bytes of `p_output` 1244 * \param[out] p_output_length Upon success, contains the number of bytes of 1245 * key material placed in `p_output` 1246 * 1247 * \retval #PSA_SUCCESS 1248 */ 1249 typedef psa_status_t (*psa_drv_se_key_derivation_export_t)(void *op_context, 1250 uint8_t *p_output, 1251 size_t output_size, 1252 size_t *p_output_length); 1253 1254 /** 1255 * \brief A struct containing all of the function pointers needed to for secure 1256 * element key derivation and agreement 1257 * 1258 * PSA Crypto API implementations should populate instances of the table as 1259 * appropriate upon startup. 1260 * 1261 * If one of the functions is not implemented, it should be set to NULL. 1262 */ 1263 typedef struct { 1264 /** The driver-specific size of the key derivation context */ 1265 size_t context_size; 1266 /** Function that performs a key derivation setup */ 1267 psa_drv_se_key_derivation_setup_t p_setup; 1268 /** Function that sets key derivation collateral */ 1269 psa_drv_se_key_derivation_collateral_t p_collateral; 1270 /** Function that performs a final key derivation step */ 1271 psa_drv_se_key_derivation_derive_t p_derive; 1272 /** Function that perforsm a final key derivation or agreement and 1273 * exports the key */ 1274 psa_drv_se_key_derivation_export_t p_export; 1275 } psa_drv_se_key_derivation_t; 1276 1277 /**@}*/ 1278 1279 /** \defgroup se_registration Secure element driver registration 1280 */ 1281 /**@{*/ 1282 1283 /** A structure containing pointers to all the entry points of a 1284 * secure element driver. 1285 * 1286 * Future versions of this specification may add extra substructures at 1287 * the end of this structure. 1288 */ 1289 typedef struct { 1290 /** The version of the driver HAL that this driver implements. 1291 * This is a protection against loading driver binaries built against 1292 * a different version of this specification. 1293 * Use #PSA_DRV_SE_HAL_VERSION. 1294 */ 1295 uint32_t hal_version; 1296 1297 /** The size of the driver's persistent data in bytes. 1298 * 1299 * This can be 0 if the driver does not need persistent data. 1300 * 1301 * See the documentation of psa_drv_se_context_t::persistent_data 1302 * for more information about why and how a driver can use 1303 * persistent data. 1304 */ 1305 size_t persistent_data_size; 1306 1307 /** The driver initialization function. 1308 * 1309 * This function is called once during the initialization of the 1310 * PSA Cryptography subsystem, before any other function of the 1311 * driver is called. If this function returns a failure status, 1312 * the driver will be unusable, at least until the next system reset. 1313 * 1314 * If this field is \c NULL, it is equivalent to a function that does 1315 * nothing and returns #PSA_SUCCESS. 1316 */ 1317 psa_drv_se_init_t p_init; 1318 1319 const psa_drv_se_key_management_t *key_management; 1320 const psa_drv_se_mac_t *mac; 1321 const psa_drv_se_cipher_t *cipher; 1322 const psa_drv_se_aead_t *aead; 1323 const psa_drv_se_asymmetric_t *asymmetric; 1324 const psa_drv_se_key_derivation_t *derivation; 1325 } psa_drv_se_t; 1326 1327 /** The current version of the secure element driver HAL. 1328 */ 1329 /* 0.0.0 patchlevel 5 */ 1330 #define PSA_DRV_SE_HAL_VERSION 0x00000005 1331 1332 /** Register an external cryptoprocessor (secure element) driver. 1333 * 1334 * This function is only intended to be used by driver code, not by 1335 * application code. In implementations with separation between the 1336 * PSA cryptography module and applications, this function should 1337 * only be available to callers that run in the same memory space as 1338 * the cryptography module, and should not be exposed to applications 1339 * running in a different memory space. 1340 * 1341 * This function may be called before psa_crypto_init(). It is 1342 * implementation-defined whether this function may be called 1343 * after psa_crypto_init(). 1344 * 1345 * \note Implementations store metadata about keys including the lifetime 1346 * value, which contains the driver's location indicator. Therefore, 1347 * from one instantiation of the PSA Cryptography 1348 * library to the next one, if there is a key in storage with a certain 1349 * lifetime value, you must always register the same driver (or an 1350 * updated version that communicates with the same secure element) 1351 * with the same location value. 1352 * 1353 * \param location The location value through which this driver will 1354 * be exposed to applications. 1355 * This driver will be used for all keys such that 1356 * `location == #PSA_KEY_LIFETIME_GET_LOCATION( lifetime )`. 1357 * The value #PSA_KEY_LOCATION_LOCAL_STORAGE is reserved 1358 * and may not be used for drivers. Implementations 1359 * may reserve other values. 1360 * \param[in] methods The method table of the driver. This structure must 1361 * remain valid for as long as the cryptography 1362 * module keeps running. It is typically a global 1363 * constant. 1364 * 1365 * \return #PSA_SUCCESS 1366 * The driver was successfully registered. Applications can now 1367 * use \p lifetime to access keys through the methods passed to 1368 * this function. 1369 * \return #PSA_ERROR_BAD_STATE 1370 * This function was called after the initialization of the 1371 * cryptography module, and this implementation does not support 1372 * driver registration at this stage. 1373 * \return #PSA_ERROR_ALREADY_EXISTS 1374 * There is already a registered driver for this value of \p lifetime. 1375 * \return #PSA_ERROR_INVALID_ARGUMENT 1376 * \p lifetime is a reserved value. 1377 * \return #PSA_ERROR_NOT_SUPPORTED 1378 * `methods->hal_version` is not supported by this implementation. 1379 * \return #PSA_ERROR_INSUFFICIENT_MEMORY 1380 * \return #PSA_ERROR_NOT_PERMITTED 1381 */ 1382 psa_status_t psa_register_se_driver( 1383 psa_key_location_t location, 1384 const psa_drv_se_t *methods); 1385 1386 /**@}*/ 1387 1388 #ifdef __cplusplus 1389 } 1390 #endif 1391 1392 #endif /* PSA_CRYPTO_SE_DRIVER_H */ 1393
