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* \file psa/crypto_types.h
* \brief PSA cryptography module: type aliases.
* \note This file may not be included directly. Applications must
* include psa/crypto.h. Drivers must include the appropriate driver
* header file.
* This file contains portable definitions of integral types for properties
* of cryptographic keys, designations of cryptographic algorithms, and
* error codes returned by the library.
* This header file does not declare any function.
* 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
* 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.
#include "crypto_platform.h"
#include <stdint.h>
/** \defgroup error Error codes
* @{
* \brief Function return status.
* This is either #PSA_SUCCESS (which is zero), indicating success,
* or a small negative value indicating that an error occurred. Errors are
* encoded as one of the \c PSA_ERROR_xxx values defined here. */
/* If #PSA_SUCCESS is already defined, it means that #psa_status_t
* is also defined in an external header, so prevent its multiple
* definition.
typedef int32_t psa_status_t;
/** \defgroup crypto_types Key and algorithm types
* @{
/** \brief Encoding of a key type.
typedef uint16_t psa_key_type_t;
/** The type of PSA elliptic curve family identifiers.
* The curve identifier is required to create an ECC key using the
* macros.
* Values defined by this standard will never be in the range 0x80-0xff.
* Vendors who define additional families must use an encoding in this range.
typedef uint8_t psa_ecc_family_t;
/** The type of PSA Diffie-Hellman group family identifiers.
* The group identifier is required to create an Diffie-Hellman key using the
* macros.
* Values defined by this standard will never be in the range 0x80-0xff.
* Vendors who define additional families must use an encoding in this range.
typedef uint8_t psa_dh_family_t;
/** \brief Encoding of a cryptographic algorithm.
* For algorithms that can be applied to multiple key types, this type
* does not encode the key type. For example, for symmetric ciphers
* based on a block cipher, #psa_algorithm_t encodes the block cipher
* mode and the padding mode while the block cipher itself is encoded
* via #psa_key_type_t.
typedef uint32_t psa_algorithm_t;
/** \defgroup key_lifetimes Key lifetimes
* @{
/** Encoding of key lifetimes.
* The lifetime of a key indicates where it is stored and what system actions
* may create and destroy it.
* Lifetime values have the following structure:
* - Bits 0-7 (#PSA_KEY_LIFETIME_GET_PERSISTENCE(\c lifetime)):
* persistence level. This value indicates what device management
* actions can cause it to be destroyed. In particular, it indicates
* whether the key is _volatile_ or _persistent_.
* See ::psa_key_persistence_t for more information.
* - Bits 8-31 (#PSA_KEY_LIFETIME_GET_LOCATION(\c lifetime)):
* location indicator. This value indicates where the key is stored
* and where operations on the key are performed.
* See ::psa_key_location_t for more information.
* Volatile keys are automatically destroyed when the application instance
* terminates or on a power reset of the device. Persistent keys are
* preserved until the application explicitly destroys them or until an
* implementation-specific device management event occurs (for example,
* a factory reset).
* Persistent keys have a key identifier of type #mbedtls_svc_key_id_t.
* This identifier remains valid throughout the lifetime of the key,
* even if the application instance that created the key terminates.
* The application can call psa_open_key() to open a persistent key that
* it created previously.
* This specification defines two basic lifetime values:
* - Keys with the lifetime #PSA_KEY_LIFETIME_VOLATILE are volatile.
* All implementations should support this lifetime.
* - Keys with the lifetime #PSA_KEY_LIFETIME_PERSISTENT are persistent.
* All implementations that have access to persistent storage with
* appropriate security guarantees should support this lifetime.
typedef uint32_t psa_key_lifetime_t;
/** Encoding of key persistence levels.
* What distinguishes different persistence levels is what device management
* events may cause keys to be destroyed. _Volatile_ keys are destroyed
* by a power reset. Persistent keys may be destroyed by events such as
* a transfer of ownership or a factory reset. What management events
* actually affect persistent keys at different levels is outside the
* scope of the PSA Cryptography specification.
* This specification defines the following values of persistence levels:
* - \c 0 = #PSA_KEY_PERSISTENCE_VOLATILE: volatile key.
* A volatile key is automatically destroyed by the implementation when
* the application instance terminates. In particular, a volatile key
* is automatically destroyed on a power reset of the device.
* persistent key with a default lifetime.
* Implementations should support this value if they support persistent
* keys at all.
* Applications should use this value if they have no specific needs that
* are only met by implementation-specific features.
* - \c 2-127: persistent key with a PSA-specified lifetime.
* The PSA Cryptography specification does not define the meaning of these
* values, but other PSA specifications may do so.
* - \c 128-254: persistent key with a vendor-specified lifetime.
* No PSA specification will define the meaning of these values, so
* implementations may choose the meaning freely.
* As a guideline, higher persistence levels should cause a key to survive
* more management events than lower levels.
* read-only or write-once key.
* A key with this persistence level cannot be destroyed.
* Implementations that support such keys may either allow their creation
* through the PSA Cryptography API, preferably only to applications with
* the appropriate privilege, or only expose keys created through
* implementation-specific means such as a factory ROM engraving process.
* Note that keys that are read-only due to policy restrictions
* rather than due to physical limitations should not have this
* persistence levels.
* \note Key persistence levels are 8-bit values. Key management
* interfaces operate on lifetimes (type ::psa_key_lifetime_t) which
* encode the persistence as the lower 8 bits of a 32-bit value.
typedef uint8_t psa_key_persistence_t;
/** Encoding of key location indicators.
* If an implementation of this API can make calls to external
* cryptoprocessors such as secure elements, the location of a key
* indicates which secure element performs the operations on the key.
* If an implementation offers multiple physical locations for persistent
* storage, the location indicator reflects at which physical location
* the key is stored.
* This specification defines the following values of location indicators:
* - \c 0: primary local storage.
* All implementations should support this value.
* The primary local storage is typically the same storage area that
* contains the key metadata.
* - \c 1: primary secure element.
* Implementations should support this value if there is a secure element
* attached to the operating environment.
* As a guideline, secure elements may provide higher resistance against
* side channel and physical attacks than the primary local storage, but may
* have restrictions on supported key types, sizes, policies and operations
* and may have different performance characteristics.
* - \c 2-0x7fffff: other locations defined by a PSA specification.
* The PSA Cryptography API does not currently assign any meaning to these
* locations, but future versions of this specification or other PSA
* specifications may do so.
* - \c 0x800000-0xffffff: vendor-defined locations.
* No PSA specification will assign a meaning to locations in this range.
* \note Key location indicators are 24-bit values. Key management
* interfaces operate on lifetimes (type ::psa_key_lifetime_t) which
* encode the location as the upper 24 bits of a 32-bit value.
typedef uint32_t psa_key_location_t;
/** Encoding of identifiers of persistent keys.
* - Applications may freely choose key identifiers in the range
* - Implementations may define additional key identifiers in the range
* - 0 is reserved as an invalid key identifier.
* - Key identifiers outside these ranges are reserved for future use.
typedef uint32_t psa_key_id_t;
typedef psa_key_id_t mbedtls_svc_key_id_t;
/* Implementation-specific: The Mbed Cryptography library can be built as
* part of a multi-client service that exposes the PSA Cryptograpy API in each
* client and encodes the client identity in the key identifier argument of
* functions such as psa_open_key().
typedef struct
psa_key_id_t key_id;
mbedtls_key_owner_id_t owner;
} mbedtls_svc_key_id_t;
/** \defgroup policy Key policies
* @{
/** \brief Encoding of permitted usage on a key. */
typedef uint32_t psa_key_usage_t;
/** \defgroup attributes Key attributes
* @{
/** The type of a structure containing key attributes.
* This is an opaque structure that can represent the metadata of a key
* object. Metadata that can be stored in attributes includes:
* - The location of the key in storage, indicated by its key identifier
* and its lifetime.
* - The key's policy, comprising usage flags and a specification of
* the permitted algorithm(s).
* - Information about the key itself: the key type and its size.
* - Implementations may define additional attributes.
* The actual key material is not considered an attribute of a key.
* Key attributes do not contain information that is generally considered
* highly confidential.
* An attribute structure can be a simple data structure where each function
* `psa_set_key_xxx` sets a field and the corresponding function
* `psa_get_key_xxx` retrieves the value of the corresponding field.
* However, implementations may report values that are equivalent to the
* original one, but have a different encoding. For example, an
* implementation may use a more compact representation for types where
* many bit-patterns are invalid or not supported, and store all values
* that it does not support as a special marker value. In such an
* implementation, after setting an invalid value, the corresponding
* get function returns an invalid value which may not be the one that
* was originally stored.
* An attribute structure may contain references to auxiliary resources,
* for example pointers to allocated memory or indirect references to
* pre-calculated values. In order to free such resources, the application
* must call psa_reset_key_attributes(). As an exception, calling
* psa_reset_key_attributes() on an attribute structure is optional if
* the structure has only been modified by the following functions
* since it was initialized or last reset with psa_reset_key_attributes():
* - psa_set_key_id()
* - psa_set_key_lifetime()
* - psa_set_key_type()
* - psa_set_key_bits()
* - psa_set_key_usage_flags()
* - psa_set_key_algorithm()
* Before calling any function on a key attribute structure, the application
* must initialize it by any of the following means:
* - Set the structure to all-bits-zero, for example:
* \code
* psa_key_attributes_t attributes;
* memset(&attributes, 0, sizeof(attributes));
* \endcode
* - Initialize the structure to logical zero values, for example:
* \code
* psa_key_attributes_t attributes = {0};
* \endcode
* - Initialize the structure to the initializer #PSA_KEY_ATTRIBUTES_INIT,
* for example:
* \code
* psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
* \endcode
* - Assign the result of the function psa_key_attributes_init()
* to the structure, for example:
* \code
* psa_key_attributes_t attributes;
* attributes = psa_key_attributes_init();
* \endcode
* A freshly initialized attribute structure contains the following
* values:
* - key identifier: 0 (which is not a valid key identifier).
* - type: \c 0 (meaning that the type is unspecified).
* - key size: \c 0 (meaning that the size is unspecified).
* - usage flags: \c 0 (which allows no usage except exporting a public key).
* - algorithm: \c 0 (which allows no cryptographic usage, but allows
* exporting).
* A typical sequence to create a key is as follows:
* -# Create and initialize an attribute structure.
* -# If the key is persistent, call psa_set_key_id().
* Also call psa_set_key_lifetime() to place the key in a non-default
* location.
* -# Set the key policy with psa_set_key_usage_flags() and
* psa_set_key_algorithm().
* -# Set the key type with psa_set_key_type().
* Skip this step if copying an existing key with psa_copy_key().
* -# When generating a random key with psa_generate_key() or deriving a key
* with psa_key_derivation_output_key(), set the desired key size with
* psa_set_key_bits().
* -# Call a key creation function: psa_import_key(), psa_generate_key(),
* psa_key_derivation_output_key() or psa_copy_key(). This function reads
* the attribute structure, creates a key with these attributes, and
* outputs a key identifier to the newly created key.
* -# The attribute structure is now no longer necessary.
* You may call psa_reset_key_attributes(), although this is optional
* with the workflow presented here because the attributes currently
* defined in this specification do not require any additional resources
* beyond the structure itself.
* A typical sequence to query a key's attributes is as follows:
* -# Call psa_get_key_attributes().
* -# Call `psa_get_key_xxx` functions to retrieve the attribute(s) that
* you are interested in.
* -# Call psa_reset_key_attributes() to free any resources that may be
* used by the attribute structure.
* Once a key has been created, it is impossible to change its attributes.
typedef struct psa_key_attributes_s psa_key_attributes_t;
#ifndef __DOXYGEN_ONLY__
/* Mbed Crypto 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. */
typedef uint64_t psa_key_slot_number_t;
#endif /* !__DOXYGEN_ONLY__ */
/** \defgroup derivation Key derivation
* @{
/** \brief Encoding of the step of a key derivation. */
typedef uint16_t psa_key_derivation_step_t;
#endif /* PSA_CRYPTO_TYPES_H */