/** * \file psa/crypto_se_driver.h * \brief PSA external cryptoprocessor driver module * * 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. */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef PSA_CRYPTO_SE_DRIVER_H #define PSA_CRYPTO_SE_DRIVER_H #include "mbedtls/private_access.h" #include "crypto_driver_common.h" #ifdef __cplusplus extern "C" { #endif /** \defgroup se_init Secure element driver initialization */ /**@{*/ /** \brief Driver context structure * * 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. */ psa_drv_se_context_t; /** \brief A driver initialization function. * * \param[in,out] drv_context The driver context structure. * \param[in,out] 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. * * \retval #PSA_SUCCESS * The driver is operational. * The core will update the persistent data in storage. * \return * Any other return value prevents the driver from being used in * this session. * The core will NOT update the persistent data in storage. */ psa_drv_se_init_t; #if defined(__DOXYGEN_ONLY__) || !defined(MBEDTLS_PSA_CRYPTO_SE_C) /* Mbed TLS with secure element support enabled defines this type in * crypto_types.h because it is also visible to applications through an * implementation-specific extension. * For the PSA Cryptography specification, this type is only visible * via crypto_se_driver.h. */ /** An internal designation of a key slot between the core part of the * PSA Crypto implementation and the driver. The meaning of this value * is driver-dependent. */ psa_key_slot_number_t; #endif /* __DOXYGEN_ONLY__ || !MBEDTLS_PSA_CRYPTO_SE_C */ /**@}*/ /** \defgroup se_mac Secure Element Message Authentication Codes * 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[in,out] drv_context The driver context structure. * \param[in,out] op_context A structure that will contain the * hardware-specific MAC context * \param[in] key_slot The slot of the key to be used for the * operation * \param[in] algorithm The algorithm to be used to underly the MAC * operation * * \retval #PSA_SUCCESS * Success. */ psa_drv_se_mac_setup_t; /** \brief A function that continues a previously started secure element MAC * operation * * \param[in,out] op_context A hardware-specific structure for the * previously-established MAC operation to be * updated * \param[in] p_input A buffer containing the message to be appended * to the MAC operation * \param[in] input_length The size in bytes of the input message buffer */ psa_drv_se_mac_update_t; /** \brief a function that completes a previously started secure element MAC * operation by returning the resulting MAC. * * \param[in,out] op_context A hardware-specific structure for the * previously started MAC operation to be * finished * \param[out] p_mac A buffer where the generated MAC will be * placed * \param[in] mac_size The size in bytes of the buffer that has been * allocated for the `output` buffer * \param[out] p_mac_length After completion, will contain the number of * bytes placed in the `p_mac` buffer * * \retval #PSA_SUCCESS * Success. */ psa_drv_se_mac_finish_t; /** \brief A function that completes a previously started secure element MAC * operation by comparing the resulting MAC against a provided value * * \param[in,out] op_context A hardware-specific structure for the previously * started MAC operation to be finished * \param[in] p_mac The MAC value against which the resulting MAC * will be compared against * \param[in] mac_length The size in bytes of the value stored in `p_mac` * * \retval #PSA_SUCCESS * The operation completed successfully and the MACs matched each * other * \retval #PSA_ERROR_INVALID_SIGNATURE * The operation completed successfully, but the calculated MAC did * not match the provided MAC */ psa_drv_se_mac_finish_verify_t; /** \brief A function that aborts a previous started secure element MAC * operation * * \param[in,out] op_context A hardware-specific structure for the previously * started MAC operation to be aborted */ psa_drv_se_mac_abort_t; /** \brief A function that performs a secure element MAC operation in one * command and returns the calculated MAC * * \param[in,out] drv_context The driver context structure. * \param[in] p_input A buffer containing the message to be MACed * \param[in] input_length The size in bytes of `p_input` * \param[in] key_slot The slot of the key to be used * \param[in] alg The algorithm to be used to underlie the MAC * operation * \param[out] p_mac A buffer where the generated MAC will be * placed * \param[in] mac_size The size in bytes of the `p_mac` buffer * \param[out] p_mac_length After completion, will contain the number of * bytes placed in the `output` buffer * * \retval #PSA_SUCCESS * Success. */ psa_drv_se_mac_generate_t; /** \brief A function that performs a secure element MAC operation in one * command and compares the resulting MAC against a provided value * * \param[in,out] drv_context The driver context structure. * \param[in] p_input A buffer containing the message to be MACed * \param[in] input_length The size in bytes of `input` * \param[in] key_slot The slot of the key to be used * \param[in] alg The algorithm to be used to underlie the MAC * operation * \param[in] p_mac The MAC value against which the resulting MAC will * be compared against * \param[in] mac_length The size in bytes of `mac` * * \retval #PSA_SUCCESS * The operation completed successfully and the MACs matched each * other * \retval #PSA_ERROR_INVALID_SIGNATURE * The operation completed successfully, but the calculated MAC did * not match the provided MAC */ psa_drv_se_mac_verify_t; /** \brief A struct containing all of the function pointers needed to * perform secure element MAC operations * * PSA Crypto API implementations should populate the table as appropriate * upon startup. * * If one of the functions is not implemented (such as * `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 `p_setup`, they should also support * `p_update` and at least one of `p_finish` or `p_finish_verify`). * */ psa_drv_se_mac_t; /**@}*/ /** \defgroup se_cipher Secure Element Symmetric Ciphers * * Encryption and Decryption using secure element keys in block modes other * than ECB must be done in multiple parts, using the following flow: * - `psa_drv_se_cipher_setup_t` * - `psa_drv_se_cipher_set_iv_t` (optional depending upon block mode) * - `psa_drv_se_cipher_update_t` * - `psa_drv_se_cipher_update_t` * - ... * - `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 `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 `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[in,out] drv_context The driver context structure. * \param[in,out] op_context A structure that will contain the * hardware-specific cipher context. * \param[in] key_slot The slot of the key to be used for the * operation * \param[in] algorithm The algorithm to be used in the cipher * operation * \param[in] direction Indicates whether the operation is an encrypt * or decrypt * * \retval #PSA_SUCCESS \emptydescription * \retval #PSA_ERROR_NOT_SUPPORTED \emptydescription */ psa_drv_se_cipher_setup_t; /** \brief A function that sets the initialization vector (if * necessary) for a secure element cipher operation * * Rationale: The `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[in,out] op_context A structure that contains the previously set up * hardware-specific cipher context * \param[in] p_iv A buffer containing the initialization vector * \param[in] iv_length The size (in bytes) of the `p_iv` buffer * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_cipher_set_iv_t; /** \brief A function that continues a previously started secure element cipher * operation * * \param[in,out] op_context A hardware-specific structure for the * previously started cipher operation * \param[in] p_input A buffer containing the data to be * encrypted/decrypted * \param[in] input_size The size in bytes of the buffer pointed to * by `p_input` * \param[out] p_output The caller-allocated buffer where the * output will be placed * \param[in] output_size The allocated size in bytes of the * `p_output` buffer * \param[out] p_output_length After completion, will contain the number * of bytes placed in the `p_output` buffer * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_cipher_update_t; /** \brief A function that completes a previously started secure element cipher * operation * * \param[in,out] op_context A hardware-specific structure for the * previously started cipher operation * \param[out] p_output The caller-allocated buffer where the output * will be placed * \param[in] output_size The allocated size in bytes of the `p_output` * buffer * \param[out] p_output_length After completion, will contain the number of * bytes placed in the `p_output` buffer * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_cipher_finish_t; /** \brief A function that aborts a previously started secure element cipher * operation * * \param[in,out] op_context A hardware-specific structure for the * previously started cipher operation */ psa_drv_se_cipher_abort_t; /** \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[in,out] drv_context The driver context structure. * \param[in] key_slot The slot of the key to be used for the operation * \param[in] algorithm The algorithm to be used in the cipher operation * \param[in] direction Indicates whether the operation is an encrypt or * decrypt * \param[in] p_input A buffer containing the data to be * encrypted/decrypted * \param[in] input_size The size in bytes of the buffer pointed to by * `p_input` * \param[out] p_output The caller-allocated buffer where the output * will be placed * \param[in] output_size The allocated size in bytes of the `p_output` * buffer * * \retval #PSA_SUCCESS \emptydescription * \retval #PSA_ERROR_NOT_SUPPORTED \emptydescription */ psa_drv_se_cipher_ecb_t; /** * \brief A struct containing all of the function pointers needed to implement * cipher operations using secure elements. * * 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 * `psa_drv_se_cipher_ecb_t`), it should be set to NULL. */ psa_drv_se_cipher_t; /**@}*/ /** \defgroup se_asymmetric Secure Element Asymmetric Cryptography * * 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[in,out] drv_context The driver context structure. * \param[in] key_slot Key slot of an asymmetric key pair * \param[in] alg A signature algorithm that is compatible * with the type of `key` * \param[in] p_hash The hash to sign * \param[in] hash_length Size of the `p_hash` buffer in bytes * \param[out] p_signature Buffer where the signature is to be written * \param[in] signature_size Size of the `p_signature` buffer in bytes * \param[out] p_signature_length On success, the number of bytes * that make up the returned signature value * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_asymmetric_sign_t; /** * \brief A function that verifies the signature a hash or short message using * an asymmetric public key in a secure element * * \param[in,out] drv_context The driver context structure. * \param[in] key_slot Key slot of a public key or an asymmetric key * pair * \param[in] alg A signature algorithm that is compatible with * the type of `key` * \param[in] p_hash The hash whose signature is to be verified * \param[in] hash_length Size of the `p_hash` buffer in bytes * \param[in] p_signature Buffer containing the signature to verify * \param[in] signature_length Size of the `p_signature` buffer in bytes * * \retval #PSA_SUCCESS * The signature is valid. */ psa_drv_se_asymmetric_verify_t; /** * \brief A function that encrypts a short message with an asymmetric public * key in a secure element * * \param[in,out] drv_context The driver context structure. * \param[in] key_slot Key slot of a public key or an asymmetric key * pair * \param[in] alg An asymmetric encryption algorithm that is * compatible with the type of `key` * \param[in] p_input The message to encrypt * \param[in] input_length Size of the `p_input` buffer in bytes * \param[in] p_salt A salt or label, if supported by the * encryption algorithm * If the algorithm does not support a * salt, pass `NULL`. * If the algorithm supports an optional * salt and you do not want to pass a salt, * pass `NULL`. * For #PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is * supported. * \param[in] salt_length Size of the `p_salt` buffer in bytes * If `p_salt` is `NULL`, pass 0. * \param[out] p_output Buffer where the encrypted message is to * be written * \param[in] output_size Size of the `p_output` buffer in bytes * \param[out] p_output_length On success, the number of bytes that make up * the returned output * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_asymmetric_encrypt_t; /** * \brief A function that decrypts a short message with an asymmetric private * key in a secure element. * * \param[in,out] drv_context The driver context structure. * \param[in] key_slot Key slot of an asymmetric key pair * \param[in] alg An asymmetric encryption algorithm that is * compatible with the type of `key` * \param[in] p_input The message to decrypt * \param[in] input_length Size of the `p_input` buffer in bytes * \param[in] p_salt A salt or label, if supported by the * encryption algorithm * If the algorithm does not support a * salt, pass `NULL`. * If the algorithm supports an optional * salt and you do not want to pass a salt, * pass `NULL`. * For #PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is * supported. * \param[in] salt_length Size of the `p_salt` buffer in bytes * If `p_salt` is `NULL`, pass 0. * \param[out] p_output Buffer where the decrypted message is to * be written * \param[in] output_size Size of the `p_output` buffer in bytes * \param[out] p_output_length On success, the number of bytes * that make up the returned output * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_asymmetric_decrypt_t; /** * \brief A struct containing all of the function pointers needed to implement * asymmetric cryptographic operations using secure elements. * * 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 NULL. */ psa_drv_se_asymmetric_t; /**@}*/ /** \defgroup se_aead Secure Element Authenticated Encryption with Additional Data * 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[in,out] drv_context The driver context structure. * \param[in] key_slot Slot containing the key to use. * \param[in] algorithm The AEAD algorithm to compute * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(`alg`) is true) * \param[in] p_nonce Nonce or IV to use * \param[in] nonce_length Size of the `p_nonce` buffer in bytes * \param[in] p_additional_data Additional data that will be * authenticated but not encrypted * \param[in] additional_data_length Size of `p_additional_data` in bytes * \param[in] p_plaintext Data that will be authenticated and * encrypted * \param[in] plaintext_length Size of `p_plaintext` in bytes * \param[out] 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[in] ciphertext_size Size of the `p_ciphertext` buffer in * bytes * \param[out] p_ciphertext_length On success, the size of the output in * the `p_ciphertext` buffer * * \retval #PSA_SUCCESS * Success. */ psa_drv_se_aead_encrypt_t; /** A function that performs a secure element authenticated decryption operation * * \param[in,out] drv_context The driver context structure. * \param[in] key_slot Slot containing the key to use * \param[in] algorithm The AEAD algorithm to compute * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(`alg`) is true) * \param[in] p_nonce Nonce or IV to use * \param[in] nonce_length Size of the `p_nonce` buffer in bytes * \param[in] p_additional_data Additional data that has been * authenticated but not encrypted * \param[in] additional_data_length Size of `p_additional_data` in bytes * \param[in] 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[in] ciphertext_length Size of `p_ciphertext` in bytes * \param[out] p_plaintext Output buffer for the decrypted data * \param[in] plaintext_size Size of the `p_plaintext` buffer in * bytes * \param[out] p_plaintext_length On success, the size of the output in * the `p_plaintext` buffer * * \retval #PSA_SUCCESS * Success. */ psa_drv_se_aead_decrypt_t; /** * \brief A struct containing all of the function pointers needed to implement * secure element Authenticated Encryption with Additional Data operations * * 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. */ psa_drv_se_aead_t; /**@}*/ /** \defgroup se_key_management Secure Element Key Management * 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. */ psa_key_creation_method_t; /** \brief A function that allocates a slot for a key. * * 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 psa_drv_se_key_management_t::p_allocate * (or in some implementations * 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: * - psa_import_key(), which causes * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_IMPORT * then a call to psa_drv_se_key_management_t::p_import. * - psa_generate_key(), which causes * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_GENERATE * then a call to psa_drv_se_key_management_t::p_import. * - psa_key_derivation_output_key(), which causes * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_DERIVE * then a call to psa_drv_se_key_derivation_t::p_derive. * - psa_copy_key(), which causes * a call to `p_allocate` with \p method = #PSA_KEY_CREATION_COPY * then a call to 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 * 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 * 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 `p_allocate` (or `p_validate_slot_number`). * * \param[in,out] drv_context The driver context structure. * \param[in,out] persistent_data A pointer to the persistent data * that allows writing. * \param[in] attributes Attributes of the key. * \param method The way in which the key is being created. * \param[out] 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. * * \retval #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. * \retval #PSA_ERROR_NOT_SUPPORTED \emptydescription * \retval #PSA_ERROR_INSUFFICIENT_STORAGE \emptydescription */ psa_drv_se_allocate_key_t; /** \brief A function that determines whether a slot number is valid * for a key. * * 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 #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 * \p persistent_data. The core will save the updated persistent data at the * end of the key creation process. See the description of * ::psa_drv_se_allocate_key_t for more information. * * \param[in,out] drv_context The driver context structure. * \param[in,out] persistent_data A pointer to the persistent data * that allows writing. * \param[in] attributes Attributes of the key. * \param method The way in which the key is being created. * \param[in] key_slot Slot where the key is to be stored. * * \retval #PSA_SUCCESS * The given slot number is valid for a key with the given * attributes. * \retval #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. * \retval #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. */ psa_drv_se_validate_slot_number_t; /** \brief A function that imports a key into a secure element in binary format * * This function can support any output from psa_export_key(). Refer to the * documentation of psa_export_key() for the format for each key type. * * \param[in,out] 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[in] 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 \p data. * Drivers can call psa_get_key_lifetime(), * psa_get_key_type(), * psa_get_key_usage_flags() and * psa_get_key_algorithm() to access this * information. * \param[in] data Buffer containing the key data. * \param[in] data_length Size of the \p data buffer in bytes. * \param[out] 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. * * \retval #PSA_SUCCESS * Success. */ psa_drv_se_import_key_t; /** * \brief A function that destroys a secure element key and restore the slot to * its default state * * 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[in,out] drv_context The driver context structure. * \param[in,out] persistent_data A pointer to the persistent data * that allows writing. * \param key_slot The key slot to erase. * * \retval #PSA_SUCCESS * The slot's content, if any, has been erased. */ psa_drv_se_destroy_key_t; /** * \brief A function that exports a secure element key in binary format * * The output of this function can be passed to psa_import_key() to * create an equivalent object. * * If a key is created with `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 * `psa_export_key()` does. Refer to the * documentation of `psa_export_key()` for the format for each key type. * * \param[in,out] drv_context The driver context structure. * \param[in] key Slot whose content is to be exported. This must * be an occupied key slot. * \param[out] p_data Buffer where the key data is to be written. * \param[in] data_size Size of the `p_data` buffer in bytes. * \param[out] p_data_length On success, the number of bytes * that make up the key data. * * \retval #PSA_SUCCESS \emptydescription * \retval #PSA_ERROR_DOES_NOT_EXIST \emptydescription * \retval #PSA_ERROR_NOT_PERMITTED \emptydescription * \retval #PSA_ERROR_NOT_SUPPORTED \emptydescription * \retval #PSA_ERROR_COMMUNICATION_FAILURE \emptydescription * \retval #PSA_ERROR_HARDWARE_FAILURE \emptydescription * \retval #PSA_ERROR_CORRUPTION_DETECTED \emptydescription */ psa_drv_se_export_key_t; /** * \brief A function that generates a symmetric or asymmetric key on a secure * element * * If the key type \c type recorded in \p attributes * is asymmetric (#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 psa_export_public_key() by writing it * to the \p 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 * \p *pubkey_length set to 0 and should * implement the psa_drv_key_management_t::p_export_public function. * Some implementations do not support this feature, in which case * \p pubkey is \c NULL and \p pubkey_size is 0. * * \param[in,out] 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[in] attributes The key attributes, including the lifetime, * the key type and size, and the usage policy. * Drivers can call psa_get_key_lifetime(), * psa_get_key_type(), psa_get_key_bits(), * psa_get_key_usage_flags() and * psa_get_key_algorithm() to access this * information. * \param[out] 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 `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[out] pubkey_length On entry, this is always 0. * On success, the number of bytes written to * \p pubkey. If this is 0 or unchanged on return, * the core will not read the \p pubkey buffer, * and will instead call the driver's * psa_drv_key_management_t::p_export_public * function to export the public key when needed. */ psa_drv_se_generate_key_t; /** * \brief A struct containing all of the function pointers needed to for secure * element key management * * 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 NULL. */ psa_drv_se_key_management_t; /**@}*/ /** \defgroup driver_derivation Secure Element Key Derivation and Agreement * 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, * `psa_drv_se_key_derivation_derive` and `psa_drv_se_key_derivation_export`. * `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. * `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 problematic to manage on embedded platforms, the inputs are passed * to the driver via a function, `psa_drv_se_key_derivation_collateral`, that * is called multiple times with different `collateral_id`s. Thus, for a key * derivation algorithm that required 3 parameter inputs, the flow would look * something like: * ~~~~~~~~~~~~~{.c} * 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(); * ~~~~~~~~~~~~~ * * key agreement example: * ~~~~~~~~~~~~~{.c} * 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); * ~~~~~~~~~~~~~ */ /**@{*/ /** \brief A function that Sets up a secure element key derivation operation by * specifying the algorithm and the source key sot * * \param[in,out] drv_context The driver context structure. * \param[in,out] op_context A hardware-specific structure containing any * context information for the implementation * \param[in] kdf_alg The algorithm to be used for the key derivation * \param[in] source_key The key to be used as the source material for * the key derivation * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_key_derivation_setup_t; /** \brief A function that provides collateral (parameters) needed for a secure * element key derivation or key agreement operation * * 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[in,out] op_context A hardware-specific structure containing any * context information for the implementation * \param[in] collateral_id An ID for the collateral being provided * \param[in] p_collateral A buffer containing the collateral data * \param[in] collateral_size The size in bytes of the collateral * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_key_derivation_collateral_t; /** \brief A function that performs the final secure element key derivation * step and place the generated key material in a slot * * \param[in,out] op_context A hardware-specific structure containing any * context information for the implementation * \param[in] dest_key The slot where the generated key material * should be placed * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_key_derivation_derive_t; /** \brief A function that performs the final step of a secure element key * agreement and place the generated key material in a buffer * * \param[out] p_output Buffer in which to place the generated key * material * \param[in] output_size The size in bytes of `p_output` * \param[out] p_output_length Upon success, contains the number of bytes of * key material placed in `p_output` * * \retval #PSA_SUCCESS \emptydescription */ psa_drv_se_key_derivation_export_t; /** * \brief A struct containing all of the function pointers needed to for secure * element key derivation and agreement * * 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. */ psa_drv_se_key_derivation_t; /**@}*/ /** \defgroup se_registration Secure element driver registration */ /**@{*/ /** A structure containing pointers to all the entry points of a * secure element driver. * * Future versions of this specification may add extra substructures at * the end of this structure. */ psa_drv_se_t; /** The current version of the secure element driver HAL. */ /* 0.0.0 patchlevel 5 */ #define PSA_DRV_SE_HAL_VERSION … /** Register an external cryptoprocessor (secure element) driver. * * This function is only intended to be used by driver code, not by * application code. In implementations with separation between the * PSA cryptography module and applications, this function should * only be available to callers that run in the same memory space as * the cryptography module, and should not be exposed to applications * running in a different memory space. * * This function may be called before psa_crypto_init(). It is * implementation-defined whether this function may be called * after psa_crypto_init(). * * \note Implementations store metadata about keys including the lifetime * value, which contains the driver's location indicator. Therefore, * from one instantiation of the PSA Cryptography * library to the next one, if there is a key in storage with a certain * lifetime value, you must always register the same driver (or an * updated version that communicates with the same secure element) * with the same location value. * * \param location The location value through which this driver will * be exposed to applications. * This driver will be used for all keys such that * `location == #PSA_KEY_LIFETIME_GET_LOCATION( lifetime )`. * The value #PSA_KEY_LOCATION_LOCAL_STORAGE is reserved * and may not be used for drivers. Implementations * may reserve other values. * \param[in] methods The method table of the driver. This structure must * remain valid for as long as the cryptography * module keeps running. It is typically a global * constant. * * \return #PSA_SUCCESS * The driver was successfully registered. Applications can now * use \p location to access keys through the methods passed to * this function. * \return #PSA_ERROR_BAD_STATE * This function was called after the initialization of the * cryptography module, and this implementation does not support * driver registration at this stage. * \return #PSA_ERROR_ALREADY_EXISTS * There is already a registered driver for this value of \p location. * \return #PSA_ERROR_INVALID_ARGUMENT * \p location is a reserved value. * \return #PSA_ERROR_NOT_SUPPORTED * `methods->hal_version` is not supported by this implementation. * \return #PSA_ERROR_INSUFFICIENT_MEMORY * \return #PSA_ERROR_NOT_PERMITTED * \return #PSA_ERROR_STORAGE_FAILURE * \return #PSA_ERROR_DATA_CORRUPT */ psa_status_t psa_register_se_driver( psa_key_location_t location, const psa_drv_se_t *methods); /**@}*/ #ifdef __cplusplus } #endif #endif /* PSA_CRYPTO_SE_DRIVER_H */
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