/** * \file psa/crypto_driver.h * \brief Platform Security Architecture cryptographic driver module * * This file describes an API for driver developers to implement to enable * hardware to be called in a standardized way by a PSA Cryptographic API * implementation. The API described is not intended to be called by * application developers. */ /* * Copyright (C) 2018, ARM Limited, All Rights Reserved * 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. */ #ifndef __PSA_CRYPTO_DRIVER_H__ #define __PSA_CRYPTO_DRIVER_H__ #include #include /** The following types are redefinitions from the psa/crypto.h file. * It is intended that these will be moved to a new common header file to * avoid duplication. They are included here for expediency in publication. */ typedef uint32_t psa_status_t; typedef uint32_t psa_algorithm_t; typedef uint8_t encrypt_or_decrypt_t; typedef uint32_t psa_key_slot_t; typedef uint32_t psa_key_type_t; /** \defgroup opaque_mac Opaque Message Authentication Code */ /**@{*/ /** \brief A function that starts a MAC operation for a PSA Crypto Driver * implementation using an opaque key * * \param[in,out] p_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. */ typedef psa_status_t (*pcd_mac_opaque_setup_t)(void *p_context, psa_key_slot_t key_slot, psa_algorithm_t algorithm); /** \brief A function that continues a previously started MAC operation using * an opaque key * * \param[in,out] p_context A hardware-specific structure for the * previously-established MAC operation to be * continued * \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 */ typedef psa_status_t (*pcd_mac_opaque_update_t)(void *p_context, const uint8_t *p_input, size_t input_length); /** \brief a function that completes a previously started MAC operation by * returning the resulting MAC using an opaque key * * \param[in] p_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_output` buffer * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*pcd_mac_opaque_finish_t)(void *p_context, uint8_t *p_mac, size_t mac_size, size_t *p_mac_length); /** \brief A function that completes a previously started MAC operation by * comparing the resulting MAC against a known value using an opaque key * * \param[in] p_context A hardware-specific structure for the previously * started MAC operation to be fiinished * \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 */ typedef psa_status_t (*pcd_mac_opaque_finish_verify_t)(void *p_context, const uint8_t *p_mac, size_t mac_length); /** \brief A function that aborts a previous started opaque-key MAC operation * \param[in] p_context A hardware-specific structure for the previously * started MAC operation to be aborted */ typedef psa_status_t (*pcd_mac_opaque_abort_t)(void *p_context); /** \brief A funciton that performs a MAC operation in one command and return * the calculated MAC using an opaque key * * \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 MA * operation * \param[out] p_mac A buffer where the generated MAC will be * placed * \param[in] mac_size The size in bytes of the `output` buffer * \param[out] p_mac_length After completion, will contain the number of * bytes placed in the `output` buffer * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*pcd_mac_opaque_generate_t)(const uint8_t *p_input, size_t input_length, psa_key_slot_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 an MAC operation in one command and * compare the resulting MAC against a known value using an opaque key * * \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 */ typedef psa_status_t (*pcd_mac_opaque_verify_t)(const uint8_t *p_input, size_t input_length, psa_key_slot_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 * implement MAC operations using opaque keys. * * PSA Crypto API implementations should populate the table as appropriate * upon startup. * * If one of the functions is not implemented (such as `pcd_mac_opaque_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`). * */ struct pcd_mac_opaque_t { /**The size in bytes of the hardware-specific Opaque-MAC Context structure */ size_t context_size; /** Function that performs the setup operation */ pcd_mac_opaque_setup_t *p_setup; /** Function that performs the update operation */ pcd_mac_opaque_update_t *p_update; /** Function that completes the operation */ pcd_mac_opaque_finish_t *p_finish; /** Function that completed a MAC operation with a verify check */ pcd_mac_opaque_finish_verify_t *p_finish_verify; /** Function that aborts a previoustly started operation */ pcd_mac_opaque_abort_t *p_abort; /** Function that performs the MAC operation in one call */ pcd_mac_opaque_generate_t *p_mac; /** Function that performs the MAC and verify operation in one call */ pcd_mac_opaque_verify_t *p_mac_verify; }; /**@}*/ /** \defgroup transparent_mac Transparent Message Authentication Code */ /**@{*/ /** \brief The hardware-specific transparent-key MAC context structure * The contents of this structure are implementation dependent and are * therefore not described here. */ struct pcd_mac_transparent_context_t { // Implementation specific }; /** \brief The function prototype for the setup operation of a * transparent-key MAC operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_mac_transparent___setup * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying primitive, and `MAC_VARIANT` * is the specific variant of a MAC operation (such as HMAC or CMAC) * * \param[in,out] p_context A structure that will contain the * hardware-specific MAC context * \param[in] p_key A buffer containing the cleartext key material * to be used in the operation * \param[in] key_length The size in bytes of the key material * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*pcd_mac_transparent_setup_t)(struct pcd_mac_transparent_context_t *p_context, const uint8_t *p_key, size_t key_length); /** \brief The function prototype for the update operation of a * transparent-key MAC operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_mac_transparent___update * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm, and `MAC_VARIANT` * is the specific variant of a MAC operation (such as HMAC or CMAC) * * \param[in,out] p_context A hardware-specific structure for the * previously-established MAC operation to be * continued * \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 */ typedef psa_status_t (*pcd_mac_transparent_update_t)(struct pcd_mac_transparent_context_t *p_context, const uint8_t *p_input, size_t input_length); /** \brief The function prototype for the finish operation of a * transparent-key MAC operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_mac_transparent___finish * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm, and `MAC_VARIANT` is * the specific variant of a MAC operation (such as HMAC or CMAC) * * \param[in] p_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_length The size in bytes of the buffer that has been * allocated for the `p_mac` buffer * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*pcd_mac_transparent_finish_t)(struct pcd_mac_transparent_context_t *p_context, uint8_t *p_mac, size_t mac_length); /** \brief The function prototype for the finish and verify operation of a * transparent-key MAC operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_mac_transparent___finish_verify * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm, and `MAC_VARIANT` is * the specific variant of a MAC operation (such as HMAC or CMAC) * * \param[in] p_context A hardware-specific structure for the * previously started MAC operation to be * fiinished * \param[in] p_mac A buffer containing the MAC that will be used * for verification * \param[in] mac_length The size in bytes of the data in the `p_mac` * buffer * * \retval PSA_SUCCESS * The operation completed successfully and the comparison matched */ typedef psa_status_t (*pcd_mac_transparent_verify_finish_t)(struct pcd_mac_transparent_context_t *p_context, const uint8_t *p_mac, size_t mac_length); /** \brief The function prototype for the abort operation for a previously * started transparent-key MAC operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_mac_transparent___abort * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm, and `MAC_VARIANT` is * the specific variant of a MAC operation (such as HMAC or CMAC) * * \param[in] p_context A hardware-specific structure for the * previously started MAC operation to be * fiinished * */ typedef psa_status_t (*pcd_mac_transparent_abort_t)(struct pcd_mac_transparent_context_t *p_context); /** \brief The function prototype for a one-shot operation of a transparent-key * MAC operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_mac_transparent__ * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm, and `MAC_VARIANT` is * the specific variant of a MAC operation (such as HMAC or CMAC) * * \param[in] p_input A buffer containing the data to be MACed * \param[in] input_length The length in bytes of the `p_input` data * \param[in] p_key A buffer containing the key material to be used * for the MAC operation * \param[in] key_length The length in bytes of the `p_key` data * \param[in] alg The algorithm to be performed * \param[out] p_mac The buffer where the resulting MAC will be placed * upon success * \param[in] mac_length The length in bytes of the `p_mac` buffer */ typedef psa_status_t (*pcd_mac_transparent_t)(const uint8_t *p_input, size_t input_length, const uint8_t *p_key, size_t key_length, psa_algorithm_t alg, uint8_t *p_mac, size_t mac_length); /** \brief The function prototype for a one-shot operation of a transparent-key * MAC Verify operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_mac_transparent___verify * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm, and `MAC_VARIANT` is * the specific variant of a MAC operation (such as HMAC or CMAC) * * \param[in] p_input A buffer containing the data to be MACed * \param[in] input_length The length in bytes of the `p_input` data * \param[in] p_key A buffer containing the key material to be used * for the MAC operation * \param[in] key_length The length in bytes of the `p_key` data * \param[in] alg The algorithm to be performed * \param[in] p_mac The MAC data to be compared * \param[in] mac_length The length in bytes of the `p_mac` buffer * * \retval PSA_SUCCESS * The operation completed successfully and the comparison matched */ typedef psa_status_t (*pcd_mac_transparent_verify_t)(const uint8_t *p_input, size_t input_length, const uint8_t *p_key, size_t key_length, psa_algorithm_t alg, const uint8_t *p_mac, size_t mac_length); /**@}*/ /** \defgroup opaque_cipher Opaque Symmetric Ciphers */ /**@{*/ /** \brief A function pointer that provides the cipher setup function for * opaque-key operations * * \param[in,out] p_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 * \retval PSA_ERROR_NOT_SUPPORTED */ typedef psa_status_t (*pcd_cipher_opaque_setup_t)(void *p_context, psa_key_slot_t key_slot, psa_algorithm_t algorithm, encrypt_or_decrypt_t direction); /** \brief A function pointer that sets the initialization vector (if * necessary) for an opaque cipher operation * * Rationale: that the psa_cipher_* function set has two IV functions: one to * set the IV, and one to generate it internally. the generate function is not * necessary for the driver API as the PSA Crypto implementation can do the * generation using its RNG features. * * \param[in,out] p_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 */ typedef psa_status_t (*pcd_cipher_opaque_set_iv_t)(void *p_context, const uint8_t *p_iv, size_t iv_length); /** \brief A function that continues a previously started opaque-key cipher * operation * * \param[in,out] p_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 */ typedef psa_status_t (*pcd_cipher_opaque_update_t)(void *p_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 opaque-key cipher * operation * * \param[in] p_context A hardware-specific structure for the * previously started cipher operation * \param[out] p_output The caller-callocated 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 */ typedef psa_status_t (*pcd_cipher_opaque_finish_t)(void *p_context, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** \brief A function that aborts a previously started opaque-key cipher * operation * * \param[in] p_context A hardware-specific structure for the * previously started cipher operation */ typedef psa_status_t (*pcd_cipher_opaque_abort_t)(void *p_context); /** \brief A function that performs the ECB block mode for opaque-key cipher * operations * * Note: this function should only be used with implementations that do not * provide a needed higher-level operation. * * \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 byffer where the output will * be placed * \param[in] output_size The allocated size in bytes of the `p_output` * buffer * * \retval PSA_SUCCESS * \retval PSA_ERROR_NOT_SUPPORTED */ typedef psa_status_t (*pcd_cipher_opaque_ecb_t)(psa_key_slot_t key_slot, psa_algorithm_t algorithm, 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 opaque keys. * * PSA Crypto API implementations should populate instances of the table as * appropriate upon startup. * * If one of the functions is not implemented (such as * `pcd_cipher_opaque_ecb_t`), it should be set to NULL. */ struct pcd_cipher_opaque_t { /** The size in bytes of the hardware-specific Opaque Cipher context * structure */ size_t size; /** Function that performs the setup operation */ pcd_cipher_opaque_setup_t *p_setup; /** Function that sets the IV (if necessary) */ pcd_cipher_opaque_set_iv_t *p_set_iv; /** Function that performs the update operation */ pcd_cipher_opaque_update_t *p_update; /** Function that completes the operation */ pcd_cipher_opaque_finish_t *p_finish; /** Function that aborts the operation */ pcd_cipher_opaque_abort_t *p_abort; /** Function that performs ECB mode for the cipher * (Danger: ECB mode should not be used directly by clients of the PSA * Crypto Client API) */ pcd_cipher_opaque_ecb_t *p_ecb; }; /**@}*/ /** \defgroup transparent_cipher Transparent Block Cipher */ /**@{*/ /** \brief The hardware-specific transparent-key Cipher context structure * The contents of this structure are implementation dependent and are * therefore not described here. */ struct pcd_cipher_transparent_context_t { // Implementation specific }; /** \brief The function prototype for the setup operation of transparent-key * block cipher operations. * Functions that implement the prototype should be named in the following * conventions: * ~~~~~~~~~~~~~{.c} * pcd_cipher_transparent_setup__ * ~~~~~~~~~~~~~ * Where * - `CIPHER_NAME` is the name of the underlying block cipher (i.e. AES or DES) * - `MODE` is the block mode of the cipher operation (i.e. CBC or CTR) * or for stream ciphers: * ~~~~~~~~~~~~~{.c} * pcd_cipher_transparent_setup_ * ~~~~~~~~~~~~~ * Where `CIPHER_NAME` is the name of a stream cipher (i.e. RC4) * * \param[in,out] p_context A structure that will contain the * hardware-specific cipher context * \param[in] direction Indicates if the operation is an encrypt or a * decrypt * \param[in] p_key_data A buffer containing the cleartext key material * to be used in the operation * \param[in] key_data_size The size in bytes of the key material * * \retval PSA_SUCCESS */ typedef psa_status_t (*pcd_cipher_transparent_setup_t)(struct pcd_cipher_transparent_context_t *p_context, encrypt_or_decrypt_t direction, const uint8_t *p_key_data, size_t key_data_size); /** \brief The function prototype for the set initialization vector operation * of transparent-key block cipher operations * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_cipher_transparent_set_iv__ * ~~~~~~~~~~~~~ * Where * - `CIPHER_NAME` is the name of the underlying block cipher (i.e. AES or DES) * - `MODE` is the block mode of the cipher operation (i.e. CBC or CTR) * * \param[in,out] p_context A structure that contains the previously setup * hardware-specific cipher context * \param[in] p_iv A buffer containing the initialization vecotr * \param[in] iv_length The size in bytes of the contents of `p_iv` * * \retval PSA_SUCCESS */ typedef psa_status_t (*pcd_cipher_transparent_set_iv_t)(struct pcd_cipher_transparent_context_t *p_context, const uint8_t *p_iv, size_t iv_length); /** \brief The function prototype for the update operation of transparent-key * block cipher operations. * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_cipher_transparent_update__ * ~~~~~~~~~~~~~ * Where * - `CIPHER_NAME` is the name of the underlying block cipher (i.e. AES or DES) * - `MODE` is the block mode of the cipher operation (i.e. CBC or CTR) * * \param[in,out] p_context A hardware-specific structure for the * previously started cipher operation * \param[in] p_input A buffer containing the data to be * encrypted or decrypted * \param[in] input_size The size in bytes of the `p_input` buffer * \param[out] p_output A caller-allocated buffer where the * generated output will be placed * \param[in] output_size The 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 */ typedef psa_status_t (*pcd_cipher_transparent_update_t)(struct pcd_cipher_transparent_context_t *p_context, const uint8_t *p_input, size_t input_size, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** \brief The function prototype for the finish operation of transparent-key * block cipher operations. * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_cipher_transparent_finish__ * ~~~~~~~~~~~~~ * Where * - `CIPHER_NAME` is the name of the underlying block cipher (i.e. AES or DES) * - `MODE` is the block mode of the cipher operation (i.e. CBC or CTR) * * \param[in] p_context A hardware-specific structure for the * previously started cipher operation * \param[out] p_output A caller-allocated buffer where the generated * output will be placed * \param[in] output_size The 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 */ typedef psa_status_t (*pcd_cipher_transparent_finish_t)(struct pcd_cipher_transparent_context_t *p_context, uint8_t *p_output, size_t output_size, size_t *p_output_length); /** \brief The function prototype for the abort operation of transparent-key * block cipher operations. * * Functions that implement the following prototype should be named in the * following convention: * ~~~~~~~~~~~~~{.c} * pcd_cipher_transparent_abort__ * ~~~~~~~~~~~~~ * Where * - `CIPHER_NAME` is the name of the underlying block cipher (i.e. AES or DES) * - `MODE` is the block mode of the cipher operation (i.e. CBC or CTR) * * \param[in] p_context A hardware-specific structure for the * previously started cipher operation * * \retval PSA_SUCCESS */ typedef psa_status_t (*pcd_cipher_transparent_abort_t)(struct pcd_cipher_transparent_context_t *p_context); /**@}*/ /** \defgroup driver_digest Message Digests */ /**@{*/ /** \brief The hardware-specific hash context structure * The contents of this structure are implementation dependent and are * therefore not described here */ struct pcd_hash_context_t { // Implementation specific }; /** \brief The function prototype for the start operation of a hash (message * digest) operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_hash__setup * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying hash function * * \param[in,out] p_context A structure that will contain the * hardware-specific hash context * * \retval PSA_SUCCESS Success. */ typedef psa_status_t (*pcd_hash_setup_t)(struct pcd_hash_context_t *p_context); /** \brief The function prototype for the update operation of a hash (message * digest) operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_hash__update * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm * * \param[in,out] p_context A hardware-specific structure for the * previously-established hash operation to be * continued * \param[in] p_input A buffer containing the message to be appended * to the hash operation * \param[in] input_length The size in bytes of the input message buffer */ typedef psa_status_t (*pcd_hash_update_t)(struct pcd_hash_context_t *p_context, const uint8_t *p_input, size_t input_length); /** \brief The prototype for the finish operation of a hash (message digest) * operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_hash__finish * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm * * \param[in] p_context A hardware-specific structure for the * previously started hash operation to be * fiinished * \param[out] p_output A buffer where the generated digest will be * placed * \param[in] output_size The size in bytes of the buffer that has been * allocated for the `p_output` buffer * * \retval PSA_SUCCESS * Success. */ typedef psa_status_t (*pcd_hash_finish_t)(struct pcd_hash_context_t *p_context, uint8_t *p_output, size_t output_size); /** \brief The function prototype for the abort operation of a hash (message * digest) operation * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_hash__abort * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the underlying algorithm * * \param[in] p_context A hardware-specific structure for the previously * started hash operation to be aborted */ typedef void (*pcd_hash_abort_t)(struct pcd_hash_context_t *p_context); /**@}*/ /** \defgroup opaque_asymmetric Opaque Asymmetric Cryptography */ /**@{*/ /** * \brief A function that signs a hash or short message with a private key * * \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 or message 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 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 */ typedef psa_status_t (*pcd_asymmetric_opaque_sign_t)(psa_key_slot_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 * a public key * * \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 or message 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. */ typedef psa_status_t (*pcd_asymmetric_opaque_verify_t)(psa_key_slot_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 a public key * * \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 */ typedef psa_status_t (*pcd_asymmetric_opaque_encrypt_t)(psa_key_slot_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 Decrypt a short message with a private key. * * \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 */ typedef psa_status_t (*pcd_asymmetric_opaque_decrypt_t)(psa_key_slot_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 opaque keys. * * 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. */ struct pcd_asymmetric_opaque_t { /** Function that performs the asymmetric sign operation */ pcd_asymmetric_opaque_sign_t *p_sign; /** Function that performs the asymmetric verify operation */ pcd_asymmetric_opaque_verify_t *p_verify; /** Function that performs the asymmetric encrypt operation */ pcd_asymmetric_opaque_encrypt_t *p_encrypt; /** Function that performs the asymmetric decrypt operation */ pcd_asymmetric_opaque_decrypt_t *p_decrypt; }; /**@}*/ /** \defgroup transparent_asymmetric Transparent Asymmetric Cryptography */ /**@{*/ /** * \brief A function that signs a hash or short message with a transparent * private key * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_asymmetric__sign * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the signing algorithm * * \param[in] p_key A buffer containing the private key * material * \param[in] key_size The size in bytes of the `p_key` data * \param[in] alg A signature algorithm that is compatible * with the type of `p_key` * \param[in] p_hash The hash or message 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 */ typedef psa_status_t (*pcd_asymmetric_transparent_sign_t)(const uint8_t *p_key, size_t key_size, 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 * a transparent public key * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_asymmetric__verify * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the signing algorithm * * \param[in] p_key A buffer containing the public key material * \param[in] key_size The size in bytes of the `p_key` data * \param[in] alg A signature algorithm that is compatible with * the type of `key` * \param[in] p_hash The hash or message 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. */ typedef psa_status_t (*pcd_asymmetric_transparent_verify_t)(const uint8_t *p_key, size_t key_size, 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 a transparent public * key * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_asymmetric__encrypt * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the encryption algorithm * * \param[in] p_key A buffer containing the public key material * \param[in] key_size The size in bytes of the `p_key` data * \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 */ typedef psa_status_t (*pcd_asymmetric_transparent_encrypt_t)(const uint8_t *p_key, size_t key_size, 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 Decrypt a short message with a transparent private key * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_asymmetric__decrypt * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the encryption algorithm * * \param[in] p_key A buffer containing the private key material * \param[in] key_size The size in bytes of the `p_key` data * \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 */ typedef psa_status_t (*pcd_asymmetric_transparent_decrypt_t)(const uint8_t *p_key, size_t key_size, 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); /**@}*/ /** \defgroup aead_opaque AEAD Opaque */ /**@{*/ /** \brief Process an authenticated encryption operation using an opaque key * * \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. */ typedef psa_status_t (*psa_aead_opaque_encrypt_t)(psa_key_slot_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); /** Process an authenticated decryption operation using an opaque key * * \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. */ typedef psa_status_t (*psa_aead_opaque_decrypt_t)(psa_key_slot_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 * Authenticated Encryption with Additional Data operations using opaque keys * * 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. */ struct psa_aead_opaque_t { /** Function that performs the AEAD encrypt operation */ psa_aead_opaque_encrypt_t *p_encrypt; /** Function that performs the AEAD decrypt operation */ psa_aead_opaque_decrypt_t *p_decrypt; }; /**@}*/ /** \defgroup aead_transparent AEAD Transparent */ /**@{*/ /** Process an authenticated encryption operation. * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_aead__encrypt * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the AEAD algorithm * * \param[in] p_key A pointer to the key material * \param[in] key_length The size in bytes of the key material * \param[in] alg The AEAD algorithm to compute * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(`alg`) is true) * \param[in] nonce Nonce or IV to use * \param[in] nonce_length Size of the `nonce` buffer in bytes * \param[in] additional_data Additional data that will be MACed * but not encrypted. * \param[in] additional_data_length Size of `additional_data` in bytes * \param[in] plaintext Data that will be MACed and * encrypted. * \param[in] plaintext_length Size of `plaintext` in bytes * \param[out] 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 `ciphertext` buffer in * bytes * This must be at least * #PSA_AEAD_ENCRYPT_OUTPUT_SIZE(`alg`, * `plaintext_length`). * \param[out] ciphertext_length On success, the size of the output in * the `ciphertext` buffer * * \retval #PSA_SUCCESS */ typedef psa_status_t (*psa_aead_transparent_encrypt_t)(const uint8_t *p_key, size_t key_length, psa_algorithm_t alg, const uint8_t *nonce, size_t nonce_length, const uint8_t *additional_data, size_t additional_data_length, const uint8_t *plaintext, size_t plaintext_length, uint8_t *ciphertext, size_t ciphertext_size, size_t *ciphertext_length); /** Process an authenticated decryption operation. * * Functions that implement the prototype should be named in the following * convention: * ~~~~~~~~~~~~~{.c} * pcd_aead__decrypt * ~~~~~~~~~~~~~ * Where `ALGO` is the name of the AEAD algorithm * \param[in] p_key A pointer to the key material * \param[in] key_length The size in bytes of the key material * \param[in] alg The AEAD algorithm to compute * (\c PSA_ALG_XXX value such that * #PSA_ALG_IS_AEAD(`alg`) is true) * \param[in] nonce Nonce or IV to use * \param[in] nonce_length Size of the `nonce` buffer in bytes * \param[in] additional_data Additional data that has been MACed * but not encrypted * \param[in] additional_data_length Size of `additional_data` in bytes * \param[in] ciphertext Data that has been MACed 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 `ciphertext` in bytes * \param[out] plaintext Output buffer for the decrypted data * \param[in] plaintext_size Size of the `plaintext` buffer in * bytes * This must be at least * #PSA_AEAD_DECRYPT_OUTPUT_SIZE(`alg`, * `ciphertext_length`). * \param[out] plaintext_length On success, the size of the output * in the \b plaintext buffer * * \retval #PSA_SUCCESS * Success. */ typedef psa_status_t (*psa_aead_transparent_decrypt_t)(const uint8_t *p_key, size_t key_length, psa_algorithm_t alg, const uint8_t *nonce, size_t nonce_length, const uint8_t *additional_data, size_t additional_data_length, const uint8_t *ciphertext, size_t ciphertext_length, uint8_t *plaintext, size_t plaintext_size, size_t *plaintext_length); /**@}*/ /** \defgroup driver_rng Entropy Generation */ /**@{*/ /** \brief A hardware-specific structure for a entropy providing hardware */ struct pcd_entropy_context_t { // Implementation specific }; /** \brief Initialize an entropy driver * * * \param[in,out] p_context A hardware-specific structure * containing any context information for * the implementation * * \retval PSA_SUCCESS */ typedef psa_status_t (*pcd_entropy_init_t)(struct pcd_entropy_context_t *p_context); /** \brief Get a specified number of bytes from the entropy source * * It retrives `buffer_size` bytes of data from the entropy source. The entropy * source will always fill the provided buffer to its full size, however, most * entropy sources have biases, and the actual amount of entropy contained in * the buffer will be less than the number of bytes. * The driver will return the actual number of bytes of entropy placed in the * buffer in `p_received_entropy_bytes`. * A PSA Crypto API implementation will likely feed the output of this function * into a Digital Random Bit Generator (DRBG), and typically has a minimum * amount of entropy that it needs. * To accomplish this, the PSA Crypto implementation should be designed to call * this function multiple times until it has received the required amount of * entropy from the entropy source. * * \param[in,out] p_context A hardware-specific structure * containing any context information * for the implementation * \param[out] p_buffer A caller-allocated buffer for the * retrieved bytes to be placed in * \param[in] buffer_size The allocated size of `p_buffer` * \param[out] p_received_entropy_bytes The amount of entropy (in bytes) * actually provided in `p_buffer` * * \retval PSA_SUCCESS */ typedef psa_status_t (*pcd_entropy_get_bytes_t)(struct pcd_entropy_context_t *p_context, uint8_t *p_buffer, uint32_t buffer_size, uint32_t *p_received_entropy_bytes); /** * \brief A struct containing all of the function pointers needed to interface * to an entropy source * * 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. */ struct pcd_entropy_t { /** Function that performs initialization for the entropy source */ pcd_entropy_init_t *p_init; /** Function that performs the get_bytes operation for the entropy source */ pcd_entropy_get_bytes_t *p_get_bytes; }; /**@}*/ /** \defgroup driver_key_management Key Management */ /**@{*/ /** \brief Import a key 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] 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] type Key type (a \c PSA_KEY_TYPE_XXX value). * \param[in] p_data Buffer containing the key data. * \param[in] data_length Size of the `data` buffer in bytes. * * \retval #PSA_SUCCESS * Success. */ typedef psa_status_t (*pcd_opaque_import_key_t)(psa_key_slot_t key_slot, psa_key_type_t type, const uint8_t *p_data, size_t data_length); /** * \brief Destroy a key and restore the slot to its default state * * This function destroys the content of the key slot from both volatile * memory and, if applicable, non-volatile storage. Implementations shall * make a best effort to ensure that any previous content of the slot is * unrecoverable. * * This function also erases any metadata such as policies. It returns the * specified slot to its default state. * * \param[in] key_slot The key slot to erase. * * \retval #PSA_SUCCESS * The slot's content, if any, has been erased. */ typedef psa_status_t (*pcd_destroy_key_t)(psa_key_slot_t key); /** * \brief Export a 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. * * For standard key types, the output format is as follows: * * - For symmetric keys (including MAC keys), the format is the * raw bytes of the key. * - For DES, the key data consists of 8 bytes. The parity bits must be * correct. * - For Triple-DES, the format is the concatenation of the * two or three DES keys. * - For RSA key pairs (#PSA_KEY_TYPE_RSA_KEYPAIR), the format * is the non-encrypted DER representation defined by PKCS\#1 (RFC 8017) * as RSAPrivateKey. * - For RSA public keys (#PSA_KEY_TYPE_RSA_PUBLIC_KEY), the format * is the DER representation defined by RFC 5280 as SubjectPublicKeyInfo. * * \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 * \retval #PSA_ERROR_EMPTY_SLOT * \retval #PSA_ERROR_NOT_PERMITTED * \retval #PSA_ERROR_NOT_SUPPORTED * \retval #PSA_ERROR_COMMUNICATION_FAILURE * \retval #PSA_ERROR_HARDWARE_FAILURE * \retval #PSA_ERROR_TAMPERING_DETECTED */ typedef psa_status_t (*pcd_export_key_t)(psa_key_slot_t key, uint8_t *p_data, size_t data_size, size_t *p_data_length); /** * \brief Export a public key or the public part of a key pair in binary format * * The output of this function can be passed to psa_import_key() to * create an object that is equivalent to the public key. * * For standard key types, the output format is as follows: * * - For RSA keys (#PSA_KEY_TYPE_RSA_KEYPAIR or #PSA_KEY_TYPE_RSA_PUBLIC_KEY), * the format is the DER representation of the public key defined by RFC 5280 * as SubjectPublicKeyInfo. * * \param[in] key_slot 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 `data` buffer in bytes. * \param[out] p_data_length On success, the number of bytes * that make up the key data. * * \retval #PSA_SUCCESS */ typedef psa_status_t (*pcd_export_public_key_t)(psa_key_slot_t key, uint8_t *p_data, size_t data_size, size_t *p_data_length); /** * \brief A struct containing all of the function pointers needed to for key * management using opaque keys * * 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. */ struct pcd_key_management_t { /** Function that performs the key import operation */ pcd_opaque_import_key_t *p_import; /** Function that performs the key destroy operation */ pcd_destroy_key_t *p_destroy; /** Function that performs the key export operation */ pcd_export_key_t *p_export; /** Function that perforsm the public key export operation */ pcd_export_public_key_t *p_export_public; }; /**@}*/ /** \defgroup driver_derivation 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 API uses the same functions * for both of the flows. * * There are two different final functions for the flows, * `pcd_key_derivation_derive` and `pcd_key_derivation_export`. * `pcd_key_derivation_derive` is used when the key material should be placed * in a slot on the hardware and not exposed to the caller. * `pcd_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, `pcd_key_derivation_collateral`, that is * called multiple times with different `collateral_id`s. Thus, for a key * derivation algorithm that required 3 paramter inputs, the flow would look * something like: * ~~~~~~~~~~~~~{.c} * pcd_key_derivation_setup(kdf_algorithm, source_key, dest_key_size_bytes); * pcd_key_derivation_collateral(kdf_algorithm_collateral_id_0, * p_collateral_0, * collateral_0_size); * pcd_key_derivation_collateral(kdf_algorithm_collateral_id_1, * p_collateral_1, * collateral_1_size); * pcd_key_derivation_collateral(kdf_algorithm_collateral_id_2, * p_collateral_2, * collateral_2_size); * pcd_key_derivation_derive(); * ~~~~~~~~~~~~~ * * key agreement example: * ~~~~~~~~~~~~~{.c} * pcd_key_derivation_setup(alg, source_key. dest_key_size_bytes); * pcd_key_derivation_collateral(DHE_PUBKEY, p_pubkey, pubkey_size); * pcd_key_derivation_export(p_session_key, * session_key_size, * &session_key_length); * ~~~~~~~~~~~~~ */ struct pcd_key_derivation_context_t { // Implementation specific }; /** \brief Set up a key derivation operation by specifying the algorithm and * the source key sot * * \param[in,out] p_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] souce_key The key to be used as the source material for the * key derivation * * \retval PSA_SUCCESS */ typedef psa_status_t (*pcd_key_derivation_setup_t)(struct pcd_key_derivation_context_t *p_context, psa_algorithm_t kdf_alg, psa_key_slot_t source_key); /** \brief Provide collateral (parameters) needed for a key derivation or key * agreement operation * * Since many key derivation algorithms require multiple parameters, it is * expeced that this function may be called multiple times for the same * operation, each with a different algorithm-specific `collateral_id` * * \param[in,out] p_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 */ typedef psa_status_t (*pcd_key_derivation_collateral_t)(struct pcd_key_derivation_context_t *p_context, uint32_t collateral_id, const uint8_t p_collateral, size_t collateral_size); /** \brief Perform the final key derivation step and place the generated key * material in a slot * \param[in,out] p_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 */ typedef psa_status_t (*pcd_key_derivation_derive_t)(struct pcd_key_derivation_context_t *p_context, psa_key_slot_t dest_key); /** \brief Perform the final step of a 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 */ typedef psa_status_t (*pcd_key_derivation_export_t)(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 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. */ struct pcd_key_derivation_t { /** Function that performs the key derivation setup */ pcd_key_derivation_setup_t *p_setup; /** Function that sets the key derivation collateral */ pcd_key_derivation_collateral_t *p_collateral; /** Function that performs the final key derivation step */ pcd_key_derivation_derive_t *p_derive; /** Function that perforsm the final key derivation or agreement and * exports the key */ pcd_key_derivation_export_t *p_export; }; /**@}*/ #endif // __PSA_CRYPTO_DRIVER_H__