mbedtls/include/psa/crypto_extra.h
gabor-mezei-arm 452b0a32ad Update documentation
The return values of the functions are updated in the documetation.
All possible return values are added including nested functions' return
values. The values which cannot be returned are removed.

Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
2020-11-25 13:10:50 +01:00

659 lines
26 KiB
C

/**
* \file psa/crypto_extra.h
*
* \brief PSA cryptography module: Mbed TLS vendor extensions
*
* \note This file may not be included directly. Applications must
* include psa/crypto.h.
*
* This file is reserved for vendor-specific definitions.
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef PSA_CRYPTO_EXTRA_H
#define PSA_CRYPTO_EXTRA_H
#include "mbedtls/platform_util.h"
#include "crypto_compat.h"
#ifdef __cplusplus
extern "C" {
#endif
/* UID for secure storage seed */
#define PSA_CRYPTO_ITS_RANDOM_SEED_UID 0xFFFFFF52
/** \addtogroup attributes
* @{
*/
/** \brief Declare the enrollment algorithm for a key.
*
* An operation on a key may indifferently use the algorithm set with
* psa_set_key_algorithm() or with this function.
*
* \param[out] attributes The attribute structure to write to.
* \param alg2 A second algorithm that the key may be used
* for, in addition to the algorithm set with
* psa_set_key_algorithm().
*
* \warning Setting an enrollment algorithm is not recommended, because
* using the same key with different algorithms can allow some
* attacks based on arithmetic relations between different
* computations made with the same key, or can escalate harmless
* side channels into exploitable ones. Use this function only
* if it is necessary to support a protocol for which it has been
* verified that the usage of the key with multiple algorithms
* is safe.
*/
static inline void psa_set_key_enrollment_algorithm(
psa_key_attributes_t *attributes,
psa_algorithm_t alg2)
{
attributes->core.policy.alg2 = alg2;
}
/** Retrieve the enrollment algorithm policy from key attributes.
*
* \param[in] attributes The key attribute structure to query.
*
* \return The enrollment algorithm stored in the attribute structure.
*/
static inline psa_algorithm_t psa_get_key_enrollment_algorithm(
const psa_key_attributes_t *attributes)
{
return( attributes->core.policy.alg2 );
}
#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
/** Retrieve the slot number where a key is stored.
*
* A slot number is only defined for keys that are stored in a secure
* element.
*
* This information is only useful if the secure element is not entirely
* managed through the PSA Cryptography API. It is up to the secure
* element driver to decide how PSA slot numbers map to any other interface
* that the secure element may have.
*
* \param[in] attributes The key attribute structure to query.
* \param[out] slot_number On success, the slot number containing the key.
*
* \retval #PSA_SUCCESS
* The key is located in a secure element, and \p *slot_number
* indicates the slot number that contains it.
* \retval #PSA_ERROR_NOT_PERMITTED
* The caller is not permitted to query the slot number.
* Mbed Crypto currently does not return this error.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* The key is not located in a secure element.
*/
psa_status_t psa_get_key_slot_number(
const psa_key_attributes_t *attributes,
psa_key_slot_number_t *slot_number );
/** Choose the slot number where a key is stored.
*
* This function declares a slot number in the specified attribute
* structure.
*
* A slot number is only meaningful for keys that are stored in a secure
* element. It is up to the secure element driver to decide how PSA slot
* numbers map to any other interface that the secure element may have.
*
* \note Setting a slot number in key attributes for a key creation can
* cause the following errors when creating the key:
* - #PSA_ERROR_NOT_SUPPORTED if the selected secure element does
* not support choosing a specific slot number.
* - #PSA_ERROR_NOT_PERMITTED if the caller is not permitted to
* choose slot numbers in general or to choose this specific slot.
* - #PSA_ERROR_INVALID_ARGUMENT if the chosen slot number is not
* valid in general or not valid for this specific key.
* - #PSA_ERROR_ALREADY_EXISTS if there is already a key in the
* selected slot.
*
* \param[out] attributes The attribute structure to write to.
* \param slot_number The slot number to set.
*/
static inline void psa_set_key_slot_number(
psa_key_attributes_t *attributes,
psa_key_slot_number_t slot_number )
{
attributes->core.flags |= MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER;
attributes->slot_number = slot_number;
}
/** Remove the slot number attribute from a key attribute structure.
*
* This function undoes the action of psa_set_key_slot_number().
*
* \param[out] attributes The attribute structure to write to.
*/
static inline void psa_clear_key_slot_number(
psa_key_attributes_t *attributes )
{
attributes->core.flags &= ~MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER;
}
/** Register a key that is already present in a secure element.
*
* The key must be located in a secure element designated by the
* lifetime field in \p attributes, in the slot set with
* psa_set_key_slot_number() in the attribute structure.
* This function makes the key available through the key identifier
* specified in \p attributes.
*
* \param[in] attributes The attributes of the existing key.
*
* \retval #PSA_SUCCESS
* The key was successfully registered.
* Note that depending on the design of the driver, this may or may
* not guarantee that a key actually exists in the designated slot
* and is compatible with the specified attributes.
* \retval #PSA_ERROR_ALREADY_EXISTS
* There is already a key with the identifier specified in
* \p attributes.
* \retval #PSA_ERROR_NOT_SUPPORTED
* The secure element driver for the specified lifetime does not
* support registering a key.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \p attributes specifies a lifetime which is not located
* in a secure element.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* No slot number is specified in \p attributes,
* or the specified slot number is not valid.
* \retval #PSA_ERROR_NOT_PERMITTED
* The caller is not authorized to register the specified key slot.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
* \retval #PSA_ERROR_INSUFFICIENT_STORAGE
* \retval #PSA_ERROR_COMMUNICATION_FAILURE
* \retval #PSA_ERROR_DATA_INVALID
* \retval #PSA_ERROR_DATA_CORRUPT
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* \retval #PSA_ERROR_BAD_STATE
* The library has not been previously initialized by psa_crypto_init().
* It is implementation-dependent whether a failure to initialize
* results in this error code.
*/
psa_status_t mbedtls_psa_register_se_key(
const psa_key_attributes_t *attributes);
#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
/**@}*/
/**
* \brief Library deinitialization.
*
* This function clears all data associated with the PSA layer,
* including the whole key store.
*
* This is an Mbed TLS extension.
*/
void mbedtls_psa_crypto_free( void );
/** \brief Statistics about
* resource consumption related to the PSA keystore.
*
* \note The content of this structure is not part of the stable API and ABI
* of Mbed Crypto and may change arbitrarily from version to version.
*/
typedef struct mbedtls_psa_stats_s
{
/** Number of slots containing key material for a volatile key. */
size_t volatile_slots;
/** Number of slots containing key material for a key which is in
* internal persistent storage. */
size_t persistent_slots;
/** Number of slots containing a reference to a key in a
* secure element. */
size_t external_slots;
/** Number of slots which are occupied, but do not contain
* key material yet. */
size_t half_filled_slots;
/** Number of slots that contain cache data. */
size_t cache_slots;
/** Number of slots that are not used for anything. */
size_t empty_slots;
/** Number of slots that are locked. */
size_t locked_slots;
/** Largest key id value among open keys in internal persistent storage. */
psa_key_id_t max_open_internal_key_id;
/** Largest key id value among open keys in secure elements. */
psa_key_id_t max_open_external_key_id;
} mbedtls_psa_stats_t;
/** \brief Get statistics about
* resource consumption related to the PSA keystore.
*
* \note When Mbed Crypto is built as part of a service, with isolation
* between the application and the keystore, the service may or
* may not expose this function.
*/
void mbedtls_psa_get_stats( mbedtls_psa_stats_t *stats );
/**
* \brief Inject an initial entropy seed for the random generator into
* secure storage.
*
* This function injects data to be used as a seed for the random generator
* used by the PSA Crypto implementation. On devices that lack a trusted
* entropy source (preferably a hardware random number generator),
* the Mbed PSA Crypto implementation uses this value to seed its
* random generator.
*
* On devices without a trusted entropy source, this function must be
* called exactly once in the lifetime of the device. On devices with
* a trusted entropy source, calling this function is optional.
* In all cases, this function may only be called before calling any
* other function in the PSA Crypto API, including psa_crypto_init().
*
* When this function returns successfully, it populates a file in
* persistent storage. Once the file has been created, this function
* can no longer succeed.
*
* If any error occurs, this function does not change the system state.
* You can call this function again after correcting the reason for the
* error if possible.
*
* \warning This function **can** fail! Callers MUST check the return status.
*
* \warning If you use this function, you should use it as part of a
* factory provisioning process. The value of the injected seed
* is critical to the security of the device. It must be
* *secret*, *unpredictable* and (statistically) *unique per device*.
* You should be generate it randomly using a cryptographically
* secure random generator seeded from trusted entropy sources.
* You should transmit it securely to the device and ensure
* that its value is not leaked or stored anywhere beyond the
* needs of transmitting it from the point of generation to
* the call of this function, and erase all copies of the value
* once this function returns.
*
* This is an Mbed TLS extension.
*
* \note This function is only available on the following platforms:
* * If the compile-time option MBEDTLS_PSA_INJECT_ENTROPY is enabled.
* Note that you must provide compatible implementations of
* mbedtls_nv_seed_read and mbedtls_nv_seed_write.
* * In a client-server integration of PSA Cryptography, on the client side,
* if the server supports this feature.
* \param[in] seed Buffer containing the seed value to inject.
* \param[in] seed_size Size of the \p seed buffer.
* The size of the seed in bytes must be greater
* or equal to both #MBEDTLS_ENTROPY_MIN_PLATFORM
* and #MBEDTLS_ENTROPY_BLOCK_SIZE.
* It must be less or equal to
* #MBEDTLS_ENTROPY_MAX_SEED_SIZE.
*
* \retval #PSA_SUCCESS
* The seed value was injected successfully. The random generator
* of the PSA Crypto implementation is now ready for use.
* You may now call psa_crypto_init() and use the PSA Crypto
* implementation.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \p seed_size is out of range.
* \retval #PSA_ERROR_STORAGE_FAILURE
* There was a failure reading or writing from storage.
* \retval #PSA_ERROR_NOT_PERMITTED
* The library has already been initialized. It is no longer
* possible to call this function.
*/
psa_status_t mbedtls_psa_inject_entropy(const uint8_t *seed,
size_t seed_size);
/** \addtogroup crypto_types
* @{
*/
/** DSA public key.
*
* The import and export format is the
* representation of the public key `y = g^x mod p` as a big-endian byte
* string. The length of the byte string is the length of the base prime `p`
* in bytes.
*/
#define PSA_KEY_TYPE_DSA_PUBLIC_KEY ((psa_key_type_t)0x4002)
/** DSA key pair (private and public key).
*
* The import and export format is the
* representation of the private key `x` as a big-endian byte string. The
* length of the byte string is the private key size in bytes (leading zeroes
* are not stripped).
*
* Determinstic DSA key derivation with psa_generate_derived_key follows
* FIPS 186-4 &sect;B.1.2: interpret the byte string as integer
* in big-endian order. Discard it if it is not in the range
* [0, *N* - 2] where *N* is the boundary of the private key domain
* (the prime *p* for Diffie-Hellman, the subprime *q* for DSA,
* or the order of the curve's base point for ECC).
* Add 1 to the resulting integer and use this as the private key *x*.
*
*/
#define PSA_KEY_TYPE_DSA_KEY_PAIR ((psa_key_type_t)0x7002)
/** Whether a key type is an DSA key (pair or public-only). */
#define PSA_KEY_TYPE_IS_DSA(type) \
(PSA_KEY_TYPE_PUBLIC_KEY_OF_KEY_PAIR(type) == PSA_KEY_TYPE_DSA_PUBLIC_KEY)
#define PSA_ALG_DSA_BASE ((psa_algorithm_t)0x10040000)
/** DSA signature with hashing.
*
* This is the signature scheme defined by FIPS 186-4,
* with a random per-message secret number (*k*).
*
* \param hash_alg A hash algorithm (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
* This includes #PSA_ALG_ANY_HASH
* when specifying the algorithm in a usage policy.
*
* \return The corresponding DSA signature algorithm.
* \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_DSA(hash_alg) \
(PSA_ALG_DSA_BASE | ((hash_alg) & PSA_ALG_HASH_MASK))
#define PSA_ALG_DETERMINISTIC_DSA_BASE ((psa_algorithm_t)0x10050000)
#define PSA_ALG_DSA_DETERMINISTIC_FLAG PSA_ALG_ECDSA_DETERMINISTIC_FLAG
/** Deterministic DSA signature with hashing.
*
* This is the deterministic variant defined by RFC 6979 of
* the signature scheme defined by FIPS 186-4.
*
* \param hash_alg A hash algorithm (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
* This includes #PSA_ALG_ANY_HASH
* when specifying the algorithm in a usage policy.
*
* \return The corresponding DSA signature algorithm.
* \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_DETERMINISTIC_DSA(hash_alg) \
(PSA_ALG_DETERMINISTIC_DSA_BASE | ((hash_alg) & PSA_ALG_HASH_MASK))
#define PSA_ALG_IS_DSA(alg) \
(((alg) & ~PSA_ALG_HASH_MASK & ~PSA_ALG_DSA_DETERMINISTIC_FLAG) == \
PSA_ALG_DSA_BASE)
#define PSA_ALG_DSA_IS_DETERMINISTIC(alg) \
(((alg) & PSA_ALG_DSA_DETERMINISTIC_FLAG) != 0)
#define PSA_ALG_IS_DETERMINISTIC_DSA(alg) \
(PSA_ALG_IS_DSA(alg) && PSA_ALG_DSA_IS_DETERMINISTIC(alg))
#define PSA_ALG_IS_RANDOMIZED_DSA(alg) \
(PSA_ALG_IS_DSA(alg) && !PSA_ALG_DSA_IS_DETERMINISTIC(alg))
/* We need to expand the sample definition of this macro from
* the API definition. */
#undef PSA_ALG_IS_HASH_AND_SIGN
#define PSA_ALG_IS_HASH_AND_SIGN(alg) \
(PSA_ALG_IS_RSA_PSS(alg) || PSA_ALG_IS_RSA_PKCS1V15_SIGN(alg) || \
PSA_ALG_IS_DSA(alg) || PSA_ALG_IS_ECDSA(alg))
/**@}*/
/** \addtogroup attributes
* @{
*/
/** Custom Diffie-Hellman group.
*
* For keys of type #PSA_KEY_TYPE_DH_PUBLIC_KEY(#PSA_DH_FAMILY_CUSTOM) or
* #PSA_KEY_TYPE_DH_KEY_PAIR(#PSA_DH_FAMILY_CUSTOM), the group data comes
* from domain parameters set by psa_set_key_domain_parameters().
*/
#define PSA_DH_FAMILY_CUSTOM ((psa_dh_family_t) 0x7e)
/**
* \brief Set domain parameters for a key.
*
* Some key types require additional domain parameters in addition to
* the key type identifier and the key size. Use this function instead
* of psa_set_key_type() when you need to specify domain parameters.
*
* The format for the required domain parameters varies based on the key type.
*
* - For RSA keys (#PSA_KEY_TYPE_RSA_PUBLIC_KEY or #PSA_KEY_TYPE_RSA_KEY_PAIR),
* the domain parameter data consists of the public exponent,
* represented as a big-endian integer with no leading zeros.
* This information is used when generating an RSA key pair.
* When importing a key, the public exponent is read from the imported
* key data and the exponent recorded in the attribute structure is ignored.
* As an exception, the public exponent 65537 is represented by an empty
* byte string.
* - For DSA keys (#PSA_KEY_TYPE_DSA_PUBLIC_KEY or #PSA_KEY_TYPE_DSA_KEY_PAIR),
* the `Dss-Parms` format as defined by RFC 3279 &sect;2.3.2.
* ```
* Dss-Parms ::= SEQUENCE {
* p INTEGER,
* q INTEGER,
* g INTEGER
* }
* ```
* - For Diffie-Hellman key exchange keys
* (#PSA_KEY_TYPE_DH_PUBLIC_KEY(#PSA_DH_FAMILY_CUSTOM) or
* #PSA_KEY_TYPE_DH_KEY_PAIR(#PSA_DH_FAMILY_CUSTOM)), the
* `DomainParameters` format as defined by RFC 3279 &sect;2.3.3.
* ```
* DomainParameters ::= SEQUENCE {
* p INTEGER, -- odd prime, p=jq +1
* g INTEGER, -- generator, g
* q INTEGER, -- factor of p-1
* j INTEGER OPTIONAL, -- subgroup factor
* validationParms ValidationParms OPTIONAL
* }
* ValidationParms ::= SEQUENCE {
* seed BIT STRING,
* pgenCounter INTEGER
* }
* ```
*
* \note This function may allocate memory or other resources.
* Once you have called this function on an attribute structure,
* you must call psa_reset_key_attributes() to free these resources.
*
* \note This is an experimental extension to the interface. It may change
* in future versions of the library.
*
* \param[in,out] attributes Attribute structure where the specified domain
* parameters will be stored.
* If this function fails, the content of
* \p attributes is not modified.
* \param type Key type (a \c PSA_KEY_TYPE_XXX value).
* \param[in] data Buffer containing the key domain parameters.
* The content of this buffer is interpreted
* according to \p type as described above.
* \param data_length Size of the \p data buffer in bytes.
*
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \retval #PSA_ERROR_NOT_SUPPORTED
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
*/
psa_status_t psa_set_key_domain_parameters(psa_key_attributes_t *attributes,
psa_key_type_t type,
const uint8_t *data,
size_t data_length);
/**
* \brief Get domain parameters for a key.
*
* Get the domain parameters for a key with this function, if any. The format
* of the domain parameters written to \p data is specified in the
* documentation for psa_set_key_domain_parameters().
*
* \note This is an experimental extension to the interface. It may change
* in future versions of the library.
*
* \param[in] attributes The key attribute structure to query.
* \param[out] data On success, the key domain parameters.
* \param data_size Size of the \p data buffer in bytes.
* The buffer is guaranteed to be large
* enough if its size in bytes is at least
* the value given by
* PSA_KEY_DOMAIN_PARAMETERS_SIZE().
* \param[out] data_length On success, the number of bytes
* that make up the key domain parameters data.
*
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_BUFFER_TOO_SMALL
*/
psa_status_t psa_get_key_domain_parameters(
const psa_key_attributes_t *attributes,
uint8_t *data,
size_t data_size,
size_t *data_length);
/** Safe output buffer size for psa_get_key_domain_parameters().
*
* This macro returns a compile-time constant if its arguments are
* compile-time constants.
*
* \warning This function may call its arguments multiple times or
* zero times, so you should not pass arguments that contain
* side effects.
*
* \note This is an experimental extension to the interface. It may change
* in future versions of the library.
*
* \param key_type A supported key type.
* \param key_bits The size of the key in bits.
*
* \return If the parameters are valid and supported, return
* a buffer size in bytes that guarantees that
* psa_get_key_domain_parameters() will not fail with
* #PSA_ERROR_BUFFER_TOO_SMALL.
* If the parameters are a valid combination that is not supported
* by the implementation, this macro shall return either a
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.
*/
#define PSA_KEY_DOMAIN_PARAMETERS_SIZE(key_type, key_bits) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? sizeof(int) : \
PSA_KEY_TYPE_IS_DH(key_type) ? PSA_DH_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) : \
PSA_KEY_TYPE_IS_DSA(key_type) ? PSA_DSA_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) : \
0)
#define PSA_DH_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) \
(4 + (PSA_BITS_TO_BYTES(key_bits) + 5) * 3 /*without optional parts*/)
#define PSA_DSA_KEY_DOMAIN_PARAMETERS_SIZE(key_bits) \
(4 + (PSA_BITS_TO_BYTES(key_bits) + 5) * 2 /*p, g*/ + 34 /*q*/)
/**@}*/
/** \defgroup psa_tls_helpers TLS helper functions
* @{
*/
#if defined(MBEDTLS_ECP_C)
#include <mbedtls/ecp.h>
/** Convert an ECC curve identifier from the Mbed TLS encoding to PSA.
*
* \note This function is provided solely for the convenience of
* Mbed TLS and may be removed at any time without notice.
*
* \param grpid An Mbed TLS elliptic curve identifier
* (`MBEDTLS_ECP_DP_xxx`).
* \param[out] bits On success, the bit size of the curve.
*
* \return The corresponding PSA elliptic curve identifier
* (`PSA_ECC_FAMILY_xxx`).
* \return \c 0 on failure (\p grpid is not recognized).
*/
static inline psa_ecc_family_t mbedtls_ecc_group_to_psa( mbedtls_ecp_group_id grpid,
size_t *bits )
{
switch( grpid )
{
case MBEDTLS_ECP_DP_SECP192R1:
*bits = 192;
return( PSA_ECC_FAMILY_SECP_R1 );
case MBEDTLS_ECP_DP_SECP224R1:
*bits = 224;
return( PSA_ECC_FAMILY_SECP_R1 );
case MBEDTLS_ECP_DP_SECP256R1:
*bits = 256;
return( PSA_ECC_FAMILY_SECP_R1 );
case MBEDTLS_ECP_DP_SECP384R1:
*bits = 384;
return( PSA_ECC_FAMILY_SECP_R1 );
case MBEDTLS_ECP_DP_SECP521R1:
*bits = 521;
return( PSA_ECC_FAMILY_SECP_R1 );
case MBEDTLS_ECP_DP_BP256R1:
*bits = 256;
return( PSA_ECC_FAMILY_BRAINPOOL_P_R1 );
case MBEDTLS_ECP_DP_BP384R1:
*bits = 384;
return( PSA_ECC_FAMILY_BRAINPOOL_P_R1 );
case MBEDTLS_ECP_DP_BP512R1:
*bits = 512;
return( PSA_ECC_FAMILY_BRAINPOOL_P_R1 );
case MBEDTLS_ECP_DP_CURVE25519:
*bits = 255;
return( PSA_ECC_FAMILY_MONTGOMERY );
case MBEDTLS_ECP_DP_SECP192K1:
*bits = 192;
return( PSA_ECC_FAMILY_SECP_K1 );
case MBEDTLS_ECP_DP_SECP224K1:
*bits = 224;
return( PSA_ECC_FAMILY_SECP_K1 );
case MBEDTLS_ECP_DP_SECP256K1:
*bits = 256;
return( PSA_ECC_FAMILY_SECP_K1 );
case MBEDTLS_ECP_DP_CURVE448:
*bits = 448;
return( PSA_ECC_FAMILY_MONTGOMERY );
default:
*bits = 0;
return( 0 );
}
}
/** Convert an ECC curve identifier from the PSA encoding to Mbed TLS.
*
* \note This function is provided solely for the convenience of
* Mbed TLS and may be removed at any time without notice.
*
* \param curve A PSA elliptic curve identifier
* (`PSA_ECC_FAMILY_xxx`).
* \param byte_length The byte-length of a private key on \p curve.
*
* \return The corresponding Mbed TLS elliptic curve identifier
* (`MBEDTLS_ECP_DP_xxx`).
* \return #MBEDTLS_ECP_DP_NONE if \c curve is not recognized.
* \return #MBEDTLS_ECP_DP_NONE if \p byte_length is not
* correct for \p curve.
*/
mbedtls_ecp_group_id mbedtls_ecc_group_of_psa( psa_ecc_family_t curve,
size_t byte_length );
#endif /* MBEDTLS_ECP_C */
/**@}*/
#ifdef __cplusplus
}
#endif
#endif /* PSA_CRYPTO_EXTRA_H */