/* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * * You may obtain a copy of the License at * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** * @ingroup sys_psa_crypto * @defgroup sys_psa_crypto_se_driver PSA Crypto Secure Element Wrapper * @{ * * @file psa_crypto_se_driver.h * @brief PSA external cryptoprocessor driver module * * @details This header declares types and function signatures for cryptography * drivers that access key material via opaque references. * This is meant for cryptoprocessors that have a separate key storage from the * space in which the PSA Crypto implementation runs, typically secure * elements (SEs). * * This file is part of the PSA Crypto Driver HAL (hardware abstraction layer), * containing functions for driver developers to implement to enable hardware * to be called in a standardized way by a PSA Cryptography API * implementation. The functions comprising the driver HAL, which driver * authors implement, are not intended to be called by application developers. */ #ifndef PSA_CRYPTO_SE_DRIVER_H #define PSA_CRYPTO_SE_DRIVER_H #ifdef __cplusplus extern "C" { #endif #include #include #include "psa/crypto_values.h" #include "psa/crypto_types.h" /** * @brief Maximum size of persistent driver data in bytes */ #define PSA_MAX_PERSISTENT_DATA_SIZE (16) /** * @defgroup se_init Secure Element Driver Initialization */ /**@{*/ /** * @brief Driver context structure * * @details Driver functions receive a pointer to this structure. * Each registered driver has one instance of this structure. * * Implementations must include the fields specified here and * may include other fields. */ typedef struct { /** * A read-only pointer to the driver's persistent data. * * Drivers typically use this persistent data to keep track of * which slot numbers are available. This is only a guideline: * drivers may use the persistent data for any purpose, keeping * in mind the restrictions on when the persistent data is saved * to storage: the persistent data is only saved after calling * certain functions that receive a writable pointer to the * persistent data. * * The core allocates a memory buffer for the persistent data. * The pointer is guaranteed to be suitably aligned for any data type, * like a pointer returned by @c malloc (but the core can use any * method to allocate the buffer, not necessarily @c malloc). * * The size of this buffer is in the @c persistent_data_size field of * this structure. * * Before the driver is initialized for the first time, the content of * the persistent data is all-bits-zero. After a driver upgrade, if the * size of the persistent data has increased, the original data is padded * on the right with zeros; if the size has decreased, the original data * is truncated to the new size. * * This pointer is to read-only data. Only a few driver functions are * allowed to modify the persistent data. These functions receive a * writable pointer. These functions are: * - @ref psa_drv_se_t::p_init * - @ref psa_drv_se_key_management_t::p_allocate * - @ref psa_drv_se_key_management_t::p_destroy * * The PSA Cryptography core saves the persistent data from one * session to the next. It does this before returning from API functions * that call a driver method that is allowed to modify the persistent * data, specifically: * - @ref psa_crypto_init() causes a call to @ref psa_drv_se_t::p_init, and may call * @ref psa_drv_se_key_management_t::p_destroy to complete an action that was * interrupted by a power failure. * - Key creation functions cause a call to @ref psa_drv_se_key_management_t::p_allocate, * and may cause a call to @ref psa_drv_se_key_management_t::p_destroy in case an error * occurs. * - @ref psa_destroy_key() causes a call to @ref psa_drv_se_key_management_t::p_destroy. */ const void * persistent_data; /** * The size of @c persistent_data in bytes. * * This is always equal to the value of the @c persistent_data_size field * of the @ref psa_drv_se_t structure when the driver is registered. */ const size_t persistent_data_size; /** * Driver transient data. * * The core initializes this value to 0 and does not read or modify it * afterwards. The driver may store whatever it wants in this field. */ uintptr_t transient_data; } psa_drv_se_context_t; /** * @brief A driver initialization function. * * @param drv_context The driver context structure. * @param persistent_data A pointer to the persistent data * that allows writing. * @param location The location value for which this driver * is registered. The driver will be invoked * for all keys whose lifetime is in this * location. * * @return @ref PSA_SUCCESS The driver is operational. * The core will update the persistent data in storage. * Any other return value prevents the driver from being used in * this session. * The core will NOT update the persistent data in storage. */ typedef psa_status_t (*psa_drv_se_init_t)(psa_drv_se_context_t *drv_context, void *persistent_data, psa_key_location_t location); /** * @brief Encoding of a key slot number on a secure element. */ typedef uint64_t psa_key_slot_number_t; /**@}*/ /** * @defgroup se_mac Secure Element Message Authentication Codes * * @details Generation and authentication of Message Authentication Codes (MACs) * using a secure element can be done either as a single function call * (via the `psa_drv_se_mac_generate_t` or `psa_drv_se_mac_verify_t` functions), * or in parts using the following sequence: * - `psa_drv_se_mac_setup_t` * - `psa_drv_se_mac_update_t` * - `psa_drv_se_mac_update_t` * - ... * - `psa_drv_se_mac_finish_t` or `psa_drv_se_mac_finish_verify_t` * * If a previously started secure element MAC operation needs to be terminated, * it should be done so by the `psa_drv_se_mac_abort_t`. Failure to do so may * result in allocated resources not being freed or in other undefined * behavior. * @{ */ /** * @brief A function that starts a secure element MAC operation for a PSA * Crypto Driver implementation * * @param drv_context The driver context structure. * @param op_context A structure that will contain the * hardware-specific MAC context * @param key_slot The slot of the key to be used for the * operation * @param algorithm The algorithm to be used to underly the MAC * operation * * @return @ref PSA_SUCCESS Success. * */ typedef psa_status_t (*psa_drv_se_mac_setup_t)(psa_drv_se_context_t *drv_context, void *op_context, psa_key_slot_number_t key_slot, psa_algorithm_t algorithm); /** * @brief A function that continues a previously started secure element MAC * operation * * @param op_context A hardware-specific structure for the * previously-established MAC operation to be * updated * @param p_input A buffer containing the message to be appended * to the MAC operation * @param input_length The size in bytes of the input message buffer */ typedef psa_status_t (*psa_drv_se_mac_update_t)(void *op_context, const uint8_t *p_input, size_t input_length); /** * @brief A function that completes a previously started secure element MAC * operation by returning the resulting MAC. * * @param op_context A hardware-specific structure for the * previously started MAC operation to be * finished * @param p_mac A buffer where the generated MAC will be * placed * @param mac_size The size in bytes of the buffer that has been * allocated for the @c output buffer * @param p_mac_length After completion, will contain the number of * bytes placed in the @c p_mac buffer * * @return @ref PSA_SUCCESS Success. */ typedef psa_status_t (*psa_drv_se_mac_finish_t)(void *op_context, uint8_t *p_mac, size_t mac_size, size_t *p_mac_length); /** * @brief A function that completes a previously started secure element MAC * operation by comparing the resulting MAC against a provided value * * @param op_context A hardware-specific structure for the previously * started MAC operation to be fiinished * @param p_mac The MAC value against which the resulting MAC * will be compared against * @param mac_length The size in bytes of the value stored in @c p_mac * * @return @ref PSA_SUCCESS The operation completed successfully and the MACs * matched each other * @ref PSA_ERROR_INVALID_SIGNATURE The operation completed successfully, but the * calculated MAC did not match the provided MAC */ typedef psa_status_t (*psa_drv_se_mac_finish_verify_t)(void *op_context, const uint8_t *p_mac, size_t mac_length); /** @brief A function that aborts a previous started secure element MAC * operation * * @param op_context A hardware-specific structure for the previously * started MAC operation to be aborted */ typedef psa_status_t (*psa_drv_se_mac_abort_t)(void *op_context); /** * @brief A function that performs a secure element MAC operation in one * command and returns the calculated MAC * * @param drv_context The driver context structure. * @param p_input A buffer containing the message to be MACed * @param input_length The size in bytes of @c p_input * @param key_slot The slot of the key to be used * @param alg The algorithm to be used to underlie the MAC * operation * @param p_mac A buffer where the generated MAC will be * placed * @param mac_size The size in bytes of the @c p_mac buffer * @param p_mac_length After completion, will contain the number of * bytes placed in the @c output buffer * * @return @ref PSA_SUCCESS Success. */ typedef psa_status_t (*psa_drv_se_mac_generate_t)(psa_drv_se_context_t *drv_context, const uint8_t *p_input, size_t input_length, psa_key_slot_number_t key_slot, psa_algorithm_t alg, uint8_t *p_mac, size_t mac_size, size_t *p_mac_length); /** * @brief A function that performs a secure element MAC operation in one * command and compares the resulting MAC against a provided value * * @param drv_context The driver context structure. * @param p_input A buffer containing the message to be MACed * @param input_length The size in bytes of @c input * @param key_slot The slot of the key to be used * @param alg The algorithm to be used to underlie the MAC * operation * @param p_mac The MAC value against which the resulting MAC will * be compared against * @param mac_length The size in bytes of @c p_mac * * @return @ref PSA_SUCCESS The operation completed successfully and the MACs * matched each other * @ref PSA_ERROR_INVALID_SIGNATURE The operation completed successfully, but the * calculated MAC did not match the provided MAC */ typedef psa_status_t (*psa_drv_se_mac_verify_t)(psa_drv_se_context_t *drv_context, const uint8_t *p_input, size_t input_length, psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_mac, size_t mac_length); /** * @brief A struct containing all of the function pointers needed to * perform secure element MAC operations * * @details PSA Crypto API implementations should populate the table as appropriate * upon startup. * * If one of the functions is not implemented (such as * @ref psa_drv_se_mac_generate_t), it should be set to NULL. * * Driver implementers should ensure that they implement all of the functions * that make sense for their hardware, and that they provide a full solution * (for example, if they support @c p_setup, they should also support * @c p_update and at least one of @c p_finish or @c p_finish_verify ). * */ typedef struct { /** The size in bytes of the hardware-specific secure element MAC context structure */ size_t context_size; /** Function that performs a MAC setup operation */ psa_drv_se_mac_setup_t p_setup; /** Function that performs a MAC update operation */ psa_drv_se_mac_update_t p_update; /** Function that completes a MAC operation */ psa_drv_se_mac_finish_t p_finish; /** Function that completes a MAC operation with a verify check */ psa_drv_se_mac_finish_verify_t p_finish_verify; /** Function that aborts a previoustly started MAC operation */ psa_drv_se_mac_abort_t p_abort; /** Function that performs a MAC operation in one call */ psa_drv_se_mac_generate_t p_mac; /** Function that performs a MAC and verify operation in one call */ psa_drv_se_mac_verify_t p_mac_verify; } psa_drv_se_mac_t; /**@}*/ /** * @defgroup se_cipher Secure Element Symmetric Ciphers * * @details Encryption and Decryption using secure element keys in block modes other * than ECB must be done in multiple parts, using the following flow: * - @ref psa_drv_se_cipher_setup_t * - @ref psa_drv_se_cipher_set_iv_t (optional depending upon block mode) * - @ref psa_drv_se_cipher_update_t * - @ref psa_drv_se_cipher_update_t * - ... * - @ref psa_drv_se_cipher_finish_t * * If a previously started secure element Cipher operation needs to be * terminated, it should be done so by the @ref psa_drv_se_cipher_abort_t. Failure * to do so may result in allocated resources not being freed or in other * undefined behavior. * * In situations where a PSA Cryptographic API implementation is using a block * mode not-supported by the underlying hardware or driver, it can construct * the block mode itself, while calling the @ref psa_drv_se_cipher_ecb_t function * for the cipher operations. * @{ */ /** * @brief A function that provides the cipher setup function for a * secure element driver * * @param drv_context The driver context structure. * @param op_context A structure that will contain the * hardware-specific cipher context. * @param key_slot The slot of the key to be used for the * operation * @param algorithm The algorithm to be used in the cipher * operation * @param direction Indicates whether the operation is an encrypt * or decrypt * * @return @ref PSA_SUCCESS * @ref PSA_ERROR_NOT_SUPPORTED */ typedef psa_status_t (*psa_drv_se_cipher_setup_t)(psa_drv_se_context_t *drv_context, void *op_context, psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, psa_encrypt_or_decrypt_t direction); /** * @brief A function that sets the initialization vector (if necessary) for an secure element * cipher operation * * @details Rationale: The @c psa_se_cipher_* operation in the PSA Cryptographic API has * two IV functions: one to set the IV, and one to generate it internally. The * generate function is not necessary for the drivers to implement as the PSA * Crypto implementation can do the generation using its RNG features. * * @param op_context A structure that contains the previously set up * hardware-specific cipher context * @param p_iv A buffer containing the initialization vector * @param iv_length The size (in bytes) of the @c p_iv buffer * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_cipher_set_iv_t)(void *op_context, const uint8_t *p_iv, size_t iv_length); /** * @brief A function that continues a previously started secure element cipher * operation * * @param op_context A hardware-specific structure for the * previously started cipher operation * @param p_input A buffer containing the data to be * encrypted/decrypted * @param input_size The size in bytes of the buffer pointed to * by @c p_input * @param p_output The caller-allocated buffer where the * output will be placed * @param output_size The allocated size in bytes of the * @c p_output buffer * @param p_output_length After completion, will contain the number * of bytes placed in the @c p_output buffer * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_cipher_update_t)(void *op_context, const uint8_t *p_input, size_t input_size, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * @brief A function that completes a previously started secure element cipher * operation * * @param op_context A hardware-specific structure for the * previously started cipher operation * @param p_output The caller-allocated buffer where the output * will be placed * @param output_size The allocated size in bytes of the @c p_output * buffer * @param p_output_length After completion, will contain the number of * bytes placed in the @c p_output buffer * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_cipher_finish_t)(void *op_context, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * @brief A function that aborts a previously started secure element cipher * operation * * @param op_context A hardware-specific structure for the * previously started cipher operation */ typedef psa_status_t (*psa_drv_se_cipher_abort_t)(void *op_context); /** * @brief A function that performs the ECB block mode for secure element * cipher operations * * @note This function should only be used with implementations that do not * provide a needed higher-level operation. * * @param drv_context The driver context structure. * @param key_slot The slot of the key to be used for the operation * @param algorithm The algorithm to be used in the cipher operation * @param direction Indicates whether the operation is an encrypt or * decrypt * @param p_input A buffer containing the data to be * encrypted/decrypted * @param input_size The size in bytes of the buffer pointed to by * @c input * @param p_output The caller-allocated buffer where the output * will be placed * @param output_size The allocated size in bytes of the @c output * buffer * * @return @ref PSA_SUCCESS * @ref PSA_ERROR_NOT_SUPPORTED */ typedef psa_status_t (*psa_drv_se_cipher_ecb_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, psa_encrypt_or_decrypt_t direction, const uint8_t *p_input, size_t input_size, uint8_t *p_output, size_t output_size); /** * @brief A struct containing all of the function pointers needed to implement * cipher operations using secure elements. * * @details PSA Crypto API implementations should populate instances of the table as * appropriate upon startup or at build time. * * If one of the functions is not implemented (such as * @c psa_drv_se_cipher_ecb_t ), it should be set to NULL. */ typedef struct { /** The size in bytes of the hardware-specific secure element cipher context structure */ size_t context_size; /** Function that performs a cipher setup operation */ psa_drv_se_cipher_setup_t p_setup; /** Function that sets a cipher IV (if necessary) */ psa_drv_se_cipher_set_iv_t p_set_iv; /** Function that performs a cipher update operation */ psa_drv_se_cipher_update_t p_update; /** Function that completes a cipher operation */ psa_drv_se_cipher_finish_t p_finish; /** Function that aborts a cipher operation */ psa_drv_se_cipher_abort_t p_abort; /** * Function that performs ECB mode for a cipher operation * @warning ECB mode should not be used directly by clients of the PSA * Crypto Client API) */ psa_drv_se_cipher_ecb_t p_ecb; } psa_drv_se_cipher_t; /**@}*/ /** * @defgroup se_asymmetric Secure Element Asymmetric Cryptography * * @details Since the amount of data that can (or should) be encrypted or signed using * asymmetric keys is limited by the key size, asymmetric key operations using * keys in a secure element must be done in single function calls. * @{ */ /** * @brief A function that signs a hash or short message with a private key in * a secure element * * @param drv_context The driver context structure. * @param key_slot Key slot of an asymmetric key pair * @param alg A signature algorithm that is compatible * with the type of @c key * @param p_hash The hash to sign * @param hash_length Size of the @c p_hash buffer in bytes * @param p_signature Buffer where the signature is to be written * @param signature_size Size of the @c p_signature buffer in bytes * @param p_signature_length On success, the number of bytes * that make up the returned signature value * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_asymmetric_sign_t)( psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_hash, size_t hash_length, uint8_t *p_signature, size_t signature_size, size_t *p_signature_length); /** * @brief A function that verifies the signature a hash or short message using * an asymmetric public key in a secure element * * @param drv_context The driver context structure. * @param key_slot Key slot of a public key or an asymmetric key * pair * @param alg A signature algorithm that is compatible with * the type of @c key * @param p_hash The hash whose signature is to be verified * @param hash_length Size of the @c p_hash buffer in bytes * @param p_signature Buffer containing the signature to verify * @param signature_length Size of the @c p_signature buffer in bytes * * @return @ref PSA_SUCCESS The signature is valid. */ typedef psa_status_t (*psa_drv_se_asymmetric_verify_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_hash, size_t hash_length, const uint8_t *p_signature, size_t signature_length); /** * @brief A function that encrypts a short message with an asymmetric public * key in a secure element * * @param drv_context The driver context structure. * @param key_slot Key slot of a public key or an asymmetric key pair * @param alg An asymmetric encryption algorithm that is compatible * with the type of @c key * @param p_input The message to encrypt * @param input_length Size of the @c p_input buffer in bytes * @param p_salt A salt or label, if supported by the * encryption algorithm * If the algorithm does not support a * salt, pass @c NULL. * If the algorithm supports an optional * salt and you do not want to pass a salt, * pass @c NULL. * For @ref PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is * supported. * @param salt_length Size of the @c p_salt buffer in bytes * If @c p_salt is @c NULL, pass 0. * @param p_output Buffer where the encrypted message is to * be written * @param output_size Size of the @c p_output buffer in bytes * @param p_output_length On success, the number of bytes that make up * the returned output * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_asymmetric_encrypt_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_input, size_t input_length, const uint8_t *p_salt, size_t salt_length, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * @brief A function that decrypts a short message with an asymmetric private * key in a secure element. * * @param drv_context The driver context structure. * @param key_slot Key slot of an asymmetric key pair * @param alg An asymmetric encryption algorithm that is * compatible with the type of @c key * @param p_input The message to decrypt * @param input_length Size of the @c p_input buffer in bytes * @param p_salt A salt or label, if supported by the * encryption algorithm * If the algorithm does not support a * salt, pass @c NULL. * If the algorithm supports an optional * salt and you do not want to pass a salt, * pass @c NULL. * For #PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is * supported. * @param salt_length Size of the @c p_salt buffer in bytes * If @c p_salt is @c NULL, pass 0. * @param p_output Buffer where the decrypted message is to * be written * @param output_size Size of the @c p_output buffer in bytes * @param p_output_length On success, the number of bytes * that make up the returned output * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_asymmetric_decrypt_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, psa_algorithm_t alg, const uint8_t *p_input, size_t input_length, const uint8_t *p_salt, size_t salt_length, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * @brief A struct containing all of the function pointers needed to implement * asymmetric cryptographic operations using secure elements. * * @details PSA Crypto API implementations should populate instances of the table as * appropriate upon startup or at build time. * * If one of the functions is not implemented, it should be set to @c NULL. */ typedef struct { /** Function that performs an asymmetric sign operation */ psa_drv_se_asymmetric_sign_t p_sign; /** Function that performs an asymmetric verify operation */ psa_drv_se_asymmetric_verify_t p_verify; /** Function that performs an asymmetric encrypt operation */ psa_drv_se_asymmetric_encrypt_t p_encrypt; /** Function that performs an asymmetric decrypt operation */ psa_drv_se_asymmetric_decrypt_t p_decrypt; } psa_drv_se_asymmetric_t; /**@}*/ /** * @defgroup se_aead Secure Element Authenticated Encryption with Additional Data * * @details Authenticated Encryption with Additional Data (AEAD) operations with secure * elements must be done in one function call. While this creates a burden for * implementers as there must be sufficient space in memory for the entire * message, it prevents decrypted data from being made available before the * authentication operation is complete and the data is known to be authentic. * @{ */ /** * @brief A function that performs a secure element authenticated encryption operation * * @param drv_context The driver context structure. * @param key_slot Slot containing the key to use. * @param algorithm The AEAD algorithm to compute * (@c PSA_ALG_XXX value such that * @ref PSA_ALG_IS_AEAD(@p alg) is true) * @param p_nonce Nonce or IV to use * @param nonce_length Size of the @c p_nonce buffer in bytes * @param p_additional_data Additional data that will be * authenticated but not encrypted * @param additional_data_length Size of @c p_additional_data in bytes * @param p_plaintext Data that will be authenticated and * encrypted * @param plaintext_length Size of @c p_plaintext in bytes * @param p_ciphertext Output buffer for the authenticated and * encrypted data. The additional data is * not part of this output. For algorithms * where the encrypted data and the * authentication tag are defined as * separate outputs, the authentication * tag is appended to the encrypted data. * @param ciphertext_size Size of the @c p_ciphertext buffer in * bytes * @param p_ciphertext_length On success, the size of the output in * the @c p_ciphertext buffer * * @return @ref PSA_SUCCESS Success. */ typedef psa_status_t (*psa_drv_se_aead_encrypt_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, const uint8_t *p_nonce, size_t nonce_length, const uint8_t *p_additional_data, size_t additional_data_length, const uint8_t *p_plaintext, size_t plaintext_length, uint8_t *p_ciphertext, size_t ciphertext_size, size_t *p_ciphertext_length); /** * @brief A function that performs a secure element authenticated decryption operation * * @param drv_context The driver context structure. * @param key_slot Slot containing the key to use * @param algorithm The AEAD algorithm to compute * (@c PSA_ALG_XXX value such that * @ref PSA_ALG_IS_AEAD(@p alg) is true) * @param p_nonce Nonce or IV to use * @param nonce_length Size of the @c p_nonce buffer in bytes * @param p_additional_data Additional data that has been * authenticated but not encrypted * @param additional_data_length Size of @c p_additional_data in bytes * @param p_ciphertext Data that has been authenticated and * encrypted. * For algorithms where the encrypted data * and the authentication tag are defined * as separate inputs, the buffer must * contain the encrypted data followed by * the authentication tag. * @param ciphertext_length Size of @c p_ciphertext in bytes * @param p_plaintext Output buffer for the decrypted data * @param plaintext_size Size of the @c p_plaintext buffer in * bytes * @param p_plaintext_length On success, the size of the output in * the @c p_plaintext buffer * * @return @ref PSA_SUCCESS Success. */ typedef psa_status_t (*psa_drv_se_aead_decrypt_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, psa_algorithm_t algorithm, const uint8_t *p_nonce, size_t nonce_length, const uint8_t *p_additional_data, size_t additional_data_length, const uint8_t *p_ciphertext, size_t ciphertext_length, uint8_t *p_plaintext, size_t plaintext_size, size_t *p_plaintext_length); /** * @brief A struct containing all of the function pointers needed to implement * secure element Authenticated Encryption with Additional Data operations * * @details PSA Crypto API implementations should populate instances of the table as * appropriate upon startup. * * If one of the functions is not implemented, it should be set to NULL. */ typedef struct { /** Function that performs the AEAD encrypt operation */ psa_drv_se_aead_encrypt_t p_encrypt; /** Function that performs the AEAD decrypt operation */ psa_drv_se_aead_decrypt_t p_decrypt; } psa_drv_se_aead_t; /**@}*/ /** * @defgroup se_key_management Secure Element Key Management * * @details Currently, key management is limited to importing keys in the clear, * destroying keys, and exporting keys in the clear. * Whether a key may be exported is determined by the key policies in place * on the key slot. * * @{ */ /** * An enumeration indicating how a key is created. */ typedef enum { PSA_KEY_CREATION_IMPORT, /**< During @ref psa_import_key() */ PSA_KEY_CREATION_GENERATE, /**< During @ref psa_generate_key() */ PSA_KEY_CREATION_DERIVE, /**< During @ref psa_key_derivation_output_key() */ PSA_KEY_CREATION_COPY, /**< During @ref psa_copy_key() */ } psa_key_creation_method_t; /** * @brief A function that allocates a slot for a key. * * @details To create a key in a specific slot in a secure element, the core first calls this * function to determine a valid slot number, then calls a function to create the key * material in that slot. In nominal conditions (that is, if no error occurs), the effect * of a call to a key creation function in the PSA Cryptography API with a lifetime that * places the key in a secure element is the following: * -# The core calls @ref psa_drv_se_key_management_t::p_allocate * (or in some implementations @ref * psa_drv_se_key_management_t::p_validate_slot_number). The driver selects (or * validates) a suitable slot number given the key attributes and the state of the * secure element. * -# The core calls a key creation function in the driver. * * The key creation functions in the PSA Cryptography API are: * - @ref psa_import_key(), which causes a call to @c p_allocate with * @c method = @ref PSA_KEY_CREATION_IMPORT then a call to * @ref psa_drv_se_key_management_t::p_import. * - @ref psa_generate_key(), which causes a call to @c p_allocate with * @c method = @ref PSA_KEY_CREATION_GENERATE then a call to * @ref psa_drv_se_key_management_t::p_import. * - @ref psa_key_derivation_output_key(), which causes a call to @c p_allocate with * @p method = @ref PSA_KEY_CREATION_DERIVE then a call to * @ref psa_drv_se_key_derivation_t::p_derive. * - @ref psa_copy_key(), which causes a call to @c p_allocate with * @p method = @ref PSA_KEY_CREATION_COPY then a call to * @ref psa_drv_se_key_management_t::p_export. * * In case of errors, other behaviors are possible. * - If the PSA Cryptography subsystem dies after the first step, for example because the * device has lost power abruptly, the second step may never happen, or may happen after * a reset and re-initialization. Alternatively, after a reset and re-initialization, * the core may call @ref psa_drv_se_key_management_t::p_destroy on the slot number that * was allocated (or validated) instead of calling a key creation function. * - If an error occurs, the core may call @ref psa_drv_se_key_management_t::p_destroy on * the slot number that was allocated (or validated) instead of calling a key creation * function. * * Errors and system resets also have an impact on the driver's persistent * data. If a reset happens before the overall key creation process is * completed (before or after the second step above), it is unspecified * whether the persistent data after the reset is identical to what it * was before or after the call to @c p_allocate (or @c p_validate_slot_number). * * @param drv_context The driver context structure. * @param persistent_data A pointer to the persistent data * that allows writing. * @param attributes Attributes of the key. * @param method The way in which the key is being created. * @param key_slot Slot where the key will be stored. * This must be a valid slot for a key of the * chosen type. It must be unoccupied. * * @return @ref PSA_SUCCESS Success. The core will record @c *key_slot as the key slot where * the key is stored and will update the persistent data in storage. * @ref PSA_ERROR_NOT_SUPPORTED * @ref PSA_ERROR_INSUFFICIENT_STORAGE */ typedef psa_status_t (*psa_drv_se_allocate_key_t)( psa_drv_se_context_t *drv_context, void *persistent_data, const psa_key_attributes_t *attributes, psa_key_creation_method_t method, psa_key_slot_number_t *key_slot); /** * @brief A function that determines whether a slot number is valid for a key. * * @details To create a key in a specific slot in a secure element, the core * first calls this function to validate the choice of slot number, * then calls a function to create the key material in that slot. * See the documentation of @ref psa_drv_se_allocate_key_t for more details. * * As of the PSA Cryptography API specification version 1.0, there is no way * for applications to trigger a call to this function. However some * implementations offer the capability to create or declare a key in * a specific slot via implementation-specific means, generally for the * sake of initial device provisioning or onboarding. Such a mechanism may * be added to a future version of the PSA Cryptography API specification. * * This function may update the driver's persistent data through * @c persistent_data. The core will save the updated persistent data at the * end of the key creation process. See the description of * @ref psa_drv_se_allocate_key_t for more information. * * @param drv_context The driver context structure. * @param persistent_data A pointer to the persistent data * that allows writing. * @param attributes Attributes of the key. * @param method The way in which the key is being created. * @param key_slot Slot where the key is to be stored. * * @return @ref PSA_SUCCESS The given slot number is valid for a key with the given * attributes. * @ref PSA_ERROR_INVALID_ARGUMENT The given slot number is not valid for a key with the * given attributes. This includes the case where the slot * number is not valid at all. * @ref PSA_ERROR_ALREADY_EXISTS There is already a key with the specified slot number. * Drivers may choose to return this error from the key * creation function instead. */ typedef psa_status_t (*psa_drv_se_validate_slot_number_t)( psa_drv_se_context_t *drv_context, void *persistent_data, const psa_key_attributes_t *attributes, psa_key_creation_method_t method, psa_key_slot_number_t key_slot); /** * @brief A function that imports a key into a secure element in binary format * * @details This function can support any output from @ref psa_export_key(). Refer to the * documentation of @ref psa_export_key() for the format for each key type. * * @param drv_context The driver context structure. * @param key_slot Slot where the key will be stored. * This must be a valid slot for a key of the * chosen type. It must be unoccupied. * @param attributes The key attributes, including the lifetime, * the key type and the usage policy. * Drivers should not access the key size stored * in the attributes: it may not match the * data passed in @c data. * Drivers can call @ref psa_get_key_lifetime(), * @ref psa_get_key_type(), @ref psa_get_key_usage_flags() * and @ref psa_get_key_algorithm() to access this * information. * @param data Buffer containing the key data. * @param data_length Size of the @c data buffer in bytes. * @param bits On success, the key size in bits. The driver * must determine this value after parsing the * key according to the key type. * This value is not used if the function fails. * * @return @ref PSA_SUCCESS Success. */ typedef psa_status_t (*psa_drv_se_import_key_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, const psa_key_attributes_t *attributes, const uint8_t *data, size_t data_length, size_t *bits); /** * @brief A function that destroys a secure element key and restore the slot to * its default state * * @details This function destroys the content of the key from a secure element. * Implementations shall make a best effort to ensure that any previous content * of the slot is unrecoverable. * * This function returns the specified slot to its default state. * * @param drv_context The driver context structure. * @param persistent_data A pointer to the persistent data * that allows writing. * @param key_slot The key slot to erase. * * @return @ref PSA_SUCCESS The slot's content, if any, has been erased. */ typedef psa_status_t (*psa_drv_se_destroy_key_t)( psa_drv_se_context_t *drv_context, void *persistent_data, psa_key_slot_number_t key_slot); /** * @brief A function that exports a secure element key in binary format * * @details The output of this function can be passed to @ref psa_import_key() to * create an equivalent object. * * If a key is created with @ref psa_import_key() and then exported with * this function, it is not guaranteed that the resulting data is * identical: the implementation may choose a different representation * of the same key if the format permits it. * * This function should generate output in the same format that @ref psa_export_key() * does. Refer to the documentation of @ref psa_export_key() for the format for each key * type. * * @param drv_context The driver context structure. * @param key_slot Slot whose content is to be exported. This must be an occupied key slot. * @param p_data Buffer where the key data is to be written. * @param data_size Size of the @c p_data buffer in bytes. * @param p_data_length On success, the number of bytes that make up the key data. * * @return @ref PSA_SUCCESS * @ref PSA_ERROR_DOES_NOT_EXIST * @ref PSA_ERROR_NOT_PERMITTED * @ref PSA_ERROR_NOT_SUPPORTED * @ref PSA_ERROR_COMMUNICATION_FAILURE * @ref PSA_ERROR_HARDWARE_FAILURE * @ref PSA_ERROR_CORRUPTION_DETECTED */ typedef psa_status_t (*psa_drv_se_export_key_t)(psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, uint8_t *p_data, size_t data_size, size_t *p_data_length); /** * @brief A function that generates a symmetric or asymmetric key on a secure element * * @details If the key type @c type recorded in @c attributes is asymmetric (@ref * PSA_KEY_TYPE_IS_ASYMMETRIC(@c type) = 1), the driver may export the public key at the * time of generation, in the format documented for @ref psa_export_public_key() by * writing it to the @c pubkey buffer. * This is optional, intended for secure elements that output the public key at generation * time and that cannot export the public key later. Drivers that do not need this feature * should leave @c *pubkey_length set to 0 and should implement the * @c p_export_public function. Some implementations do not * support this feature, in which case @c pubkey is @c NULL and @c pubkey_size is 0. * * @param drv_context The driver context structure. * @param key_slot Slot where the key will be stored. This must be a valid slot for a key * of the chosen type. It must be unoccupied. * @param attributes The key attributes, including the lifetime, the key type and size, and * the usage policy. Drivers can call @ref psa_get_key_lifetime(), * @ref psa_get_key_type(), @ref psa_get_key_bits(), * @ref psa_get_key_usage_flags() and @ref psa_get_key_algorithm() to * access this information. * @param pubkey A buffer where the driver can write the public key, when generating an * asymmetric key pair. This is @c NULL when generating a symmetric key or * if the core does not support exporting the public key at generation * time. * @param pubkey_size The size of the @c pubkey buffer in bytes. This is 0 when generating a * symmetric key or if the core does not support exporting the public key * at generation time. * @param pubkey_length On entry, this is always 0. On success, the number of bytes written to * @c pubkey. If this is 0 or unchanged on return, the core will not read * the @c pubkey buffer, and will instead call the driver's * @c p_export_public function to export the * public key when needed. */ typedef psa_status_t (*psa_drv_se_generate_key_t)( psa_drv_se_context_t *drv_context, psa_key_slot_number_t key_slot, const psa_key_attributes_t *attributes, uint8_t *pubkey, size_t pubkey_size, size_t *pubkey_length); /** * @brief A struct containing all of the function pointers needed to for secure element key * management * * @details PSA Crypto API implementations should populate instances of the table as * appropriate upon startup or at build time. * * If one of the functions is not implemented, it should be set to @c NULL. */ typedef struct { /** Function that allocates a slot for a key. */ psa_drv_se_allocate_key_t p_allocate; /** Function that checks the validity of a slot for a key. */ psa_drv_se_validate_slot_number_t p_validate_slot_number; /** Function that performs a key import operation */ psa_drv_se_import_key_t p_import; /** Function that performs a generation */ psa_drv_se_generate_key_t p_generate; /** Function that performs a key destroy operation */ psa_drv_se_destroy_key_t p_destroy; /** Function that performs a key export operation */ psa_drv_se_export_key_t p_export; /** Function that performs a public key export operation */ psa_drv_se_export_key_t p_export_public; } psa_drv_se_key_management_t; /**@}*/ /** * @defgroup driver_derivation Secure Element Key Derivation and Agreement * * @details Key derivation is the process of generating new key material using an * existing key and additional parameters, iterating through a basic * cryptographic function, such as a hash. * Key agreement is a part of cryptographic protocols that allows two parties * to agree on the same key value, but starting from different original key * material. * The flows are similar, and the PSA Crypto Driver Model uses the same functions * for both of the flows. * * There are two different final functions for the flows, * @c psa_drv_se_key_derivation_derive and @c psa_drv_se_key_derivation_export. * @c psa_drv_se_key_derivation_derive is used when the key material should be * placed in a slot on the hardware and not exposed to the caller. * @c psa_drv_se_key_derivation_export is used when the key material should be * returned to the PSA Cryptographic API implementation. * * Different key derivation algorithms require a different number of inputs. * Instead of having an API that takes as input variable length arrays, which * can be problemmatic to manage on embedded platforms, the inputs are passed * to the driver via a function, @c psa_drv_se_key_derivation_collateral, that * is called multiple times with different @c collateral_ids. Thus, for a key * derivation algorithm that required 3 parameter inputs, the flow would look * something like: * * @code * psa_drv_se_key_derivation_setup(kdf_algorithm, source_key, * dest_key_size_bytes); * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_0, * p_collateral_0, * collateral_0_size); * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_1, * p_collateral_1, * collateral_1_size); * psa_drv_se_key_derivation_collateral(kdf_algorithm_collateral_id_2, * p_collateral_2, * collateral_2_size); * psa_drv_se_key_derivation_derive(); * @endcode * * key agreement example: * @code * psa_drv_se_key_derivation_setup(alg, source_key. dest_key_size_bytes); * psa_drv_se_key_derivation_collateral(DHE_PUBKEY, p_pubkey, pubkey_size); * psa_drv_se_key_derivation_export(p_session_key, * session_key_size, * &session_key_length); * @endcode * @{ */ /** * @brief A function that Sets up a secure element key derivation operation by specifying the * algorithm and the source key sot * * @param drv_context The driver context structure. * @param op_context A hardware-specific structure containing any * context information for the implementation * @param kdf_alg The algorithm to be used for the key derivation * @param source_key The key to be used as the source material for * the key derivation * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_setup_t)(psa_drv_se_context_t *drv_context, void *op_context, psa_algorithm_t kdf_alg, psa_key_slot_number_t source_key); /** * @brief A function that provides collateral (parameters) needed for a secure * element key derivation or key agreement operation * * @details Since many key derivation algorithms require multiple parameters, it is * expected that this function may be called multiple times for the same * operation, each with a different algorithm-specific `collateral_id` * * @param op_context A hardware-specific structure containing any * context information for the implementation * @param collateral_id An ID for the collateral being provided * @param p_collateral A buffer containing the collateral data * @param collateral_size The size in bytes of the collateral * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_collateral_t)(void *op_context, uint32_t collateral_id, const uint8_t *p_collateral, size_t collateral_size); /** * @brief A function that performs the final secure element key derivation * step and place the generated key material in a slot * * @param op_context A hardware-specific structure containing any * context information for the implementation * @param dest_key The slot where the generated key material should be placed * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_derive_t)(void *op_context, psa_key_slot_number_t dest_key); /** * @brief A function that performs the final step of a secure element key * agreement and place the generated key material in a buffer * * @param op_context A hardware-specific structure containing any * context information for the implementation * @param p_output Buffer in which to place the generated key material * @param output_size The size in bytes of @c p_output * @param p_output_length Upon success, contains the number of bytes of key * material placed in @c p_output * * @return @ref PSA_SUCCESS */ typedef psa_status_t (*psa_drv_se_key_derivation_export_t)(void *op_context, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** * @brief A struct containing all of the function pointers needed to for secure * element key derivation and agreement * * @details PSA Crypto API implementations should populate instances of the table as * appropriate upon startup. * * If one of the functions is not implemented, it should be set to @c NULL. */ typedef struct { /** The driver-specific size of the key derivation context */ size_t context_size; /** Function that performs a key derivation setup */ psa_drv_se_key_derivation_setup_t p_setup; /** Function that sets key derivation collateral */ psa_drv_se_key_derivation_collateral_t p_collateral; /** Function that performs a final key derivation step */ psa_drv_se_key_derivation_derive_t p_derive; /** Function that perforsm a final key derivation or agreement and exports the key */ psa_drv_se_key_derivation_export_t p_export; } psa_drv_se_key_derivation_t; /**@}*/ /** * @defgroup se_registration Secure Element Driver Registration * @{ */ /** * @brief A structure containing pointers to all the entry points of a secure element driver. * * @details Future versions of this specification may add extra substructures at the end of this * structure. */ typedef struct { /** * The version of the driver HAL that this driver implements. * This is a protection against loading driver binaries built against * a different version of this specification. * Use @ref PSA_DRV_SE_HAL_VERSION. */ uint32_t hal_version; /** * The size of the driver's persistent data in bytes. * * This can be 0 if the driver does not need persistent data. * * See the documentation of @ref psa_drv_se_context_t::persistent_data * for more information about why and how a driver can use * persistent data. */ size_t persistent_data_size; /** * The driver initialization function. * * This function is called once during the initialization of the * PSA Cryptography subsystem, before any other function of the * driver is called. If this function returns a failure status, * the driver will be unusable, at least until the next system reset. * * If this field is @c NULL, it is equivalent to a function that does * nothing and returns @ref PSA_SUCCESS. */ psa_drv_se_init_t p_init; const psa_drv_se_key_management_t *key_management; /**< Key management methods */ const psa_drv_se_mac_t *mac; /**< MAC operation methods */ const psa_drv_se_cipher_t *cipher; /**< Cipher operation methods */ const psa_drv_se_aead_t *aead; /**< AEAD operation methods */ const psa_drv_se_asymmetric_t *asymmetric; /**< Asymmetric operation methods */ const psa_drv_se_key_derivation_t *derivation; /**< Key derivation methods */ } psa_drv_se_t; /**@}*/ /** * The current version of the secure element driver HAL. */ #define PSA_DRV_SE_HAL_VERSION 0x00000005 #ifdef __cplusplus } #endif #endif /* PSA_CRYPTO_SE_DRIVER_H */ /** @} */