| ####################################### |
| Trusted Firmware-M Profile Small Design |
| ####################################### |
| |
| :Authors: David Hu |
| :Organization: Arm Limited |
| :Contact: david.hu@arm.com |
| |
| ************ |
| Introduction |
| ************ |
| |
| The capabilities and resources may dramatically vary on different IoT devices. |
| Some IoT devices may have very limited memory resource. The program on those |
| devices should keep small memory footprint and basic functionalities. |
| On the other hand, some devices may consist of more memory and extended storage, |
| to support stronger software capabilities. |
| |
| Diverse IoT use cases also require different levels of security and requirements |
| on device resource. For example, use cases require different cipher |
| capabilities. Selecting cipher suites can be sensitive to memory footprint on |
| devices with constrained resource. |
| |
| Trusted Firmware-M (TF-M) defines 3 general profiles, Profile Small, |
| Profile Medium and Profile Large, to provide different levels of security to fit |
| diverse device capabilities and use cases. |
| Each profile specifies a predefined list of features, targeting typical use |
| cases with specific hardware constraints. Profiles can serve as reference |
| designs, based on which developers can continue further development and |
| configurations, according to use case. |
| |
| As one of the TF-M Profiles, TF-M Profile Small (Profile S) consists of |
| lightweight TF-M framework and basic Secure Services to keep smallest memory |
| footprint, supporting fundamental security features on devices with ultra |
| constrained resource. |
| |
| This profile enables connecting with Edge Gateways and IoT Cloud Services |
| supporting secure connection based solely on symmetric cryptography. |
| |
| This document summarizes and discusses the features specified in TF-M Profile |
| Small. |
| |
| ************** |
| Overall design |
| ************** |
| |
| TF-M Profile Small defines the following features: |
| |
| - Lightweight framework |
| |
| - Library model |
| - Level 1 isolation |
| - Buffer sharing allowed |
| - Single secure context |
| |
| - Crypto |
| |
| - Symmetric cipher only |
| - Cipher suite for symmetric-key algorithms based protocols, such as |
| cipher suites defined in TLS pre-shared key (TLS-PSK) [1]_. |
| |
| - Advanced Encryption Standard (AES) as symmetric crypto algorithm |
| - SHA256 as Hash function |
| - HMAC as Message Authentication Code algorithm |
| |
| - Internal Trusted Storage (ITS) |
| |
| - No encryption |
| - No rollback protection |
| - Decrease internal transient buffer size |
| |
| - Initial Attestation |
| |
| - Based on symmetric key algorithms |
| |
| - Lightweight boot |
| |
| - Single image boot |
| - Anti-rollback protection is enabled |
| |
| |
| Protected Storage, audit logging and other Secure Services provided by TF-M are |
| disabled by default. |
| |
| ************** |
| Design details |
| ************** |
| |
| More details of TF-M Profile Small design are discussed in following sections. |
| |
| Lightweight framework |
| ===================== |
| |
| Library model |
| ------------- |
| |
| Profile Small selects Library model in TF-M. Library model implements secure |
| function calls, via which clients directly call secure services. It provides a |
| more simple implementation of TF-M framework and may reduce memory footprint, |
| compared with Inter-Process Communication (IPC) model [2]_. |
| |
| .. note :: |
| |
| **Implementation note** |
| |
| Please note that there is no public dedicated specification for Library |
| model. |
| The design, interfaces and implementation of Library model in TF-M may |
| change. |
| |
| Level 1 isolation |
| ----------------- |
| |
| So far, TF-M Library model only supports level 1 isolation [2]_, which isolates |
| Secure Processing Environment (SPE) from Non-secure Processing Environment |
| (NSPE). Neither level 2 nor level 3 isolation [2]_ is implemented in TF-M |
| Library model. |
| |
| PSA Root of Trust (PSA RoT) and Application Root of Trust (ARoT) are isolated |
| from each other in level 2 isolation. |
| Individual secure partitions are isolated from each other even within a |
| particular security domain (PSA RoT, ARoT), in level 3 isolation. |
| |
| Profile Small dedicated use cases with simple service model may not require |
| level 2 or level 3 isolation. Devices which Profile Small aims at may be unable |
| to implement stricter isolation, limited by hardware capabilities. |
| |
| Level 1 isolation reduces requirements enforced by hardware isolation and cost |
| of software for management. |
| |
| .. note :: |
| |
| **Security note** |
| |
| If a device or a use case enforces level 2 or level 3 isolation, it is |
| suggested to apply other configurations, other than TF-M Profile Small. |
| |
| Buffer sharing allowed |
| ---------------------- |
| |
| To simplify interface and reduce memory footprint, TF-M Library model directly |
| handles client call input vectors from non-secure client buffers and later |
| writes results back to those buffers, without keeping a copy in a transient |
| buffer inside TF-M. |
| |
| .. note :: |
| |
| **Security note** |
| |
| There can be security vulnerabilities if non-secure client buffers are |
| directly shared between NSPE and SPE, such as Time-of-check to time-of-use |
| (TOCTOU) attack. |
| |
| Developers need to check if this can meet the Security Functional |
| Requirements (SFR) of the integration of their devices. |
| Some SFRs are listed in a set of example Threat Models and Security Analyses |
| (TMSA) offered by PSA for common IoT use cases. [3]_ |
| |
| Single secure context |
| --------------------- |
| |
| TF-M Library model only supports single secure context. |
| |
| It cannot support multiple contexts or the scheduling implemented in IPC model. |
| It neither can support multiple outstanding PSA client calls. |
| |
| But correspondingly, it can save memory footprint and runtime complexity in |
| context management and scheduling. |
| |
| .. note :: |
| |
| **Security note** |
| |
| Non-secure software should prevent triggering multiple outstanding PSA |
| client calls concurrently. Otherwise, it may crash current running secure |
| context. |
| |
| Crypto service |
| ============== |
| |
| TF-M Profile Small only requires symmetric crypto since symmetric algorithms |
| require shorter keys and less computational burden, compared with asymmetric |
| crypto. |
| |
| By default, TF-M Profile Small requires the same capabilities as defined in |
| TLS-PSK, to support symmetric key algorithms based protocols. |
| |
| .. note :: |
| |
| **Implementation note** |
| |
| Please note that TF-M Profile Small doesn't require that TLS-PSK is |
| mandatory in applications. Instead, Profile Small only requires the same |
| capabilities as defined in TLS-PSK, such as one symmetric cipher algorithm |
| and one hash function. |
| |
| TF-M Profile Small selects TLS-PSK cipher suite TLS_PSK_WITH_AES_128_CCM [4]_ |
| as reference, which requires: |
| |
| - AES-128-CCM (AES CCM mode with 128-bit key) as symmetric crypto algorithm |
| - SHA256 as Hash function |
| - HMAC as Message Authentication Code algorithm |
| |
| TLS_PSK_WITH_AES_128_CCM is selected since it requires small key length and less |
| hardware capabilities, while keeping enough level of security. |
| |
| .. note :: |
| |
| **Implementation note** |
| |
| Developers can replace default algorithms with others or implement more |
| algorithms. |
| |
| Proper symmetric key algorithms and cipher suites should be selected |
| according to device capabilities, the use case and the requirement of peers |
| in connection. |
| |
| Refer to `Crypto service configuration`_ for implementation details of |
| configuring algorithms and cipher suites. |
| |
| .. note :: |
| |
| **Security note** |
| |
| It is recommended not to use MD5 or SHA-1 for message digests as they are |
| subject to collision attacks [5]_ [6]_. |
| |
| Secure Storage |
| ============== |
| |
| TF-M Profile Small assumes that extremely constrained devices only contain basic |
| on-chip storage, without external or removable storage. |
| As a result, TF-M Profile Small includes ITS service and disables Protected |
| Storage service. |
| |
| Encryption and rollback protection |
| ---------------------------------- |
| |
| Neither encryption nor rollback protection is enabled in current ITS |
| implementation. |
| |
| It is expected that ITS relies solely on the physical inaccessibility property |
| of on-chip storage, together with PSA isolation, without requiring additional |
| cryptographic protection. |
| |
| Internal transient buffer |
| ------------------------- |
| |
| ITS implements a internal transient buffer [7]_ to hold the data read |
| from/written to storage, especially for flash, to solve the alignment and |
| security issues. |
| |
| The internal transient buffer is aligned to the flash device’s program unit. |
| Copying data to it from the caller can align all write requests to the flash |
| device’s program unit. |
| The internal transient buffer can help protect Flash access from some attacks, |
| such as TOCTOU attack. |
| |
| Although removing this internal buffer can save some memory consumption, |
| typically 512 bytes, it may bring alignment or security issues. |
| Therefore, to achieve a better trade-off between memory footprint and security, |
| TF-M Profile Small optimizes the internal buffer size to 32 bytes by default. |
| |
| As discussed in `Crypto service`_, TF-M Profile Small requires AES-128 and |
| SHA-256, which use 128-bit key and 256-bit key respectively. |
| Besides, either long public/private keys or PKI-based certificates should be |
| very rare as asymmetric crypto is not supported in Profile Small. |
| Therefore, a 32-byte internal buffer should cover the assets in TF-M Profile |
| Small use cases. |
| |
| The buffer size can be adjusted according to use case and device Flash |
| attributes. Refer to `Internal Trusted Storage configurations`_ for more |
| details. |
| |
| Initial Attestation |
| =================== |
| |
| Profile Small requires an Initial Attestation secure service based on symmetric |
| key algorithms. Refer to PSA Attestation API document [8]_ for details of |
| Initial Attestation based on symmetric key algorithms. |
| |
| It can heavily increase memory footprint to support Initial Attestation based on |
| asymmetric key algorithms, due to asymmetric ciphers and related PKI modules. |
| |
| .. note :: |
| |
| **Implementation note** |
| |
| As pointed out by PSA Attestation API document [8]_, the use cases of |
| Initial Attestation based on symmetric key algorithms can be limited due to |
| the associated infrastructure costs for key management and operational |
| complexities. It may also restrict the ability to interoperate with |
| scenarios that involve third parties. |
| |
| If asymmetric key algorithms based Initial Attestation is required in use |
| scenarios, it is recommended to select other TF-M Profiles which support |
| asymmetric key algorithms. |
| |
| .. note :: |
| |
| **Implementation note** |
| |
| It is recommended to utilize the same MAC algorithm supported in Crypto |
| service to complete the signing in ``COSE_Mac0``, to minimize memory |
| footprint. |
| |
| Lightweight boot |
| ================ |
| |
| If MCUBoot provided by TF-M is enabled, single image boot [9]_ is selected by |
| default in Profile Small. |
| In case of single image boot, secure and non-secure images are handled as a |
| single blob and signed together during image generation. |
| |
| However, secure and non-secure images must be updated together in single image |
| boot. It may decrease the flexibility of image update and cost longer update |
| process. Since the image sizes should usually be small with limited |
| functionalities in Profile Small dedicated use case, the cost may still be |
| reasonable. |
| |
| BL2 implementation can be device specific. Devices may implement diverse |
| boot processes with different features and configurations. |
| However, anti-rollback protection is required as a mandatory feature of boot |
| loader. Boot loader should be able to prevent unauthorized rollback, to protect |
| devices from being downgraded to earlier versions with known vulnerabilities. |
| |
| ************** |
| Implementation |
| ************** |
| |
| Overview |
| ======== |
| |
| The basic idea is to add dedicated profile CMake configuration files under |
| folder ``config/profile`` for TF-M Profile Small default configuration. |
| |
| The top-level Profile Small config file collects all the necessary |
| configuration flags and set them to default values, to explicitly enable the |
| features required in Profile Small and disable the unnecessary ones, during |
| TF-M build. |
| |
| A platform/use case can provide a configuration extension file to overwrite |
| Profile Small default setting and append other configurations. |
| This configuration extension file can be added via parameter |
| ``TFM_EXTRA_CONFIG_PATH`` in build command line. |
| |
| The behaviour of the Profile Small build flow (particularly the order of |
| configuration loading and overriding) can be found at |
| :ref:`tfm_cmake_configuration` |
| |
| The details of configurations will be covered in each module in |
| `Implementation details`_. |
| |
| Implementation details |
| ====================== |
| |
| This section discusses the details of Profile Small implementation. |
| |
| Top-level configuration files |
| ----------------------------- |
| |
| The firmware framework configurations in ``config/profile/profile_small`` are |
| shown below. |
| |
| .. table:: TFM options in Profile Small top-level CMake config file |
| :widths: auto |
| :align: center |
| |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | Configs | Default value | Descriptions | |
| +============================================+=====================================================================================================+=====================================+ |
| | ``TFM_ISOLATION_LEVEL`` | ``1`` | Select level 2 isolation | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_PSA_API`` | ``FALSE`` | Select IPC model | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_PARTITION_INTERNAL_TRUSTED_STORAGE`` | ``ON`` | Enable ITS SP | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``ITS_BUF_SIZE`` | ``32`` | ITS internal transient buffer size | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_PARTITION_CRYPTO`` | ``ON`` | Enable Crypto service | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_MBEDCRYPTO_CONFIG_PATH`` | ``${CMAKE_SOURCE_DIR}/lib/ext/mbedcrypto/mbedcrypto_config/tfm_mbedcrypto_config_profile_small.h`` | Mbed Crypto config file path | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``CRYPTO_ASYM_SIGN_MODULE_DISABLED`` | ``ON`` | Disable asymmetric signature | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``CRYPTO_ASYM_ENCRYPT_MODULE_DISABLED`` | ``ON`` | Disable asymmetric encryption | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_PARTITION_INITIAL_ATTESTATION`` | ``ON`` | Enable Initial Attestation service | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``SYMMETRIC_INITIAL_ATTESTATION`` | ``ON`` | Enable symmetric attestation | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_PARTITION_PROTECTED_STORAGE`` | ``OFF`` | Enable PS service | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_PARTITION_PLATFORM`` | ``OFF`` | Enable TF-M Platform SP | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_PARTITION_AUDIT_LOG`` | ``OFF`` | Disable TF-M audit logging service | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| |
| .. note :: |
| |
| **Implementation note** |
| |
| The following sections focus on the feature selection via configuration |
| setting. |
| Dedicated optimization on memory footprint is not covered in this document. |
| |
| Test configuration |
| ^^^^^^^^^^^^^^^^^^ |
| |
| Standard regression test configuration applies. This means that enabling |
| regression testing via |
| |
| ``-DTEST_S=ON -DTEST_NS=ON`` |
| |
| Will enable testing for all enabled partitions. See above for details of enabled |
| partitions. Because Profile Small does not enable IPC mode, the IPC tests are |
| not enabled. |
| |
| Some cryptography tests are disabled due to the reduced Mbed Crypto config. |
| |
| .. table:: TFM options in Profile Small top-level CMake config file |
| :widths: auto |
| :align: center |
| |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | Configs | Default value | Descriptions | |
| +============================================+=====================================================================================================+=====================================+ |
| | ``TFM_CRYPTO_TEST_ALG_CBC`` | ``OFF`` | Test CBC cryptography mode | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_CRYPTO_TEST_ALG_CCM`` | ``ON`` | Test CCM cryptography mode | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_CRYPTO_TEST_ALG_CFB`` | ``OFF`` | Test CFB cryptography mode | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_CRYPTO_TEST_ALG_CTR`` | ``OFF`` | Test CTR cryptography mode | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_CRYPTO_TEST_ALG_GCM`` | ``OFF`` | Test GCM cryptography mode | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_CRYPTO_TEST_ALG_SHA_512`` | ``OFF`` | Test SHA-512 cryptography algorithm | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``TFM_CRYPTO_TEST_HKDF`` | ``OFF`` | Test SHA-512 cryptography algorithm | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| |
| Device configuration extension |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| To change default configurations and add platform specific configurations, |
| a platform can add a platform configuration file at |
| ``platform/ext<TFM_PLATFORM>/config.cmake`` |
| |
| TF-M framework setting |
| ---------------------- |
| |
| The top-level Profile Small CMake config file selects Library model and level 1 |
| isolation. |
| |
| Crypto service configuration |
| ---------------------------- |
| |
| Crypto Secure Partition |
| ^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| TF-M Profile Small enables Crypto Secure Partition (SP) in its top-level CMake |
| config file. Crypto SP modules not supported in TF-M Profile Small are disabled. |
| The disabled modules are shown below. |
| |
| - Disable asymmetric cipher |
| |
| Other modules and configurations [10]_ are kept as default values. |
| |
| Additional configuration flags with more fine granularity can be added to |
| control building of specific crypto algorithms and corresponding test cases. |
| |
| Mbed Crypto configurations |
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| |
| TF-M Profile Small adds a dedicated Mbed Crypto config file |
| ``tfm_mbedcrypto_config_profile_small.h`` at |
| ``/lib/ext/mbedcrypto/mbedcrypto_config`` |
| file, instead of the common one ``tfm_mbedcrypto_config_default.h`` [10]_. |
| |
| Major Mbed Crypto configurations are set as listed below: |
| |
| - Enable SHA256 |
| - Enable generic message digest wrappers |
| - Enable AES |
| - Enable CCM mode for symmetric ciphers |
| - Disable other modes for symmetric ciphers |
| - Disable asymmetric ciphers |
| - Disable HMAC-based key derivation function (HKDF) |
| |
| Other configurations can be selected to optimize the memory footprint of Crypto |
| module. |
| |
| A device/use case can append an extra config header to the Profile Small |
| default Mbed Crypto config file. This can be done by setting the |
| ``TFM_MBEDCRYPTO_PLATFORM_EXTRA_CONFIG_PATH`` cmake variable in the platform |
| config file ``platform/ext<TFM_PLATFORM>/config.cmake``. This cmake variable is |
| a wrapper around the ``MBEDTLS_USER_CONFIG_FILE`` options, but is preferred as |
| it keeps all configuration in cmake. |
| |
| Internal Trusted Storage configurations |
| --------------------------------------- |
| |
| ITS service is enabled in top-level Profile Small CMake config file. |
| |
| The internal transient buffer size ``ITS_BUF_SIZE`` [7]_ is set to 32 bytes by |
| default. A platform/use case can overwrite the buffer size in its specific |
| configuration extension according to its actual requirement of assets and Flash |
| attributes. |
| |
| Profile Small CMake config file won't touch the configurations of device |
| specific Flash hardware attributes [7]_. |
| |
| Initial Attestation secure service |
| ---------------------------------- |
| |
| TF-M Profile Small provides a reference implementation of symmetric key |
| algorithms based Initial Attestation, using HMAC SHA-256 as MAC algorithm in |
| ``COSE_Mac0`` structure. The implementation follows PSA Attestation API document |
| [8]_. |
| |
| Profile Small top-level config file enables Initial Attestation secure service |
| and selects symmetric key algorithms based Initial Attestation by default. |
| |
| - Set ``TFM_PARTITION_INITIAL_ATTESTATION`` to ``ON`` |
| - Set ``SYMMETRIC_INITIAL_ATTESTATION`` to ``ON`` |
| |
| Symmetric and asymmetric key algorithms based Initial Attestation can share the |
| same generations of token claims, except Instance ID claim. |
| |
| Profile Small may implement the procedure or rely on a 3rd-party tool to |
| construct and sign ``COSE_Mac0`` structure. |
| |
| Details of symmetric key algorithms based Initial Attestation design will be |
| covered in a dedicated document. |
| |
| Disabled secure services |
| ------------------------ |
| |
| Audit logging, Protected Storage, and Platform Service are disabled by default |
| in Profile Small top-level CMake config file. |
| |
| BL2 setting |
| ----------- |
| |
| Profile Small enables MCUBoot provided by TF-M by default. A platform can |
| overwrite this configuration by disabling MCUBoot in its configuration extension |
| file ``platform/ext<TFM_PLATFORM>/config.cmake``. |
| |
| If MCUBoot provided by TF-M is enabled, single image boot is selected in TF-M |
| Profile Small top-level CMake config file. |
| |
| If a device implements its own boot loader, the configurations are |
| implementation defined. |
| |
| .. table:: BL2 options in Profile Small top-level CMake config file |
| :widths: auto |
| :align: center |
| |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | Configs | Default value | Descriptions | |
| +============================================+=====================================================================================================+=====================================+ |
| | ``BL2`` | ``ON`` | Enable MCUBoot bootloader | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| | ``MCUBOOT_IMAGE_NUMBER`` | ``1`` | Combine S and NS images | |
| +--------------------------------------------+-----------------------------------------------------------------------------------------------------+-------------------------------------+ |
| |
| **************** |
| Platform support |
| **************** |
| |
| Building Profile Small |
| ====================== |
| |
| To build Profile Small, argument ``TFM_PROFILE`` in build command line should be |
| set to ``profile_small``. |
| |
| Take AN521 as an example. |
| |
| The following commands build Profile Small without test cases on **AN521** with |
| build type **MinSizeRel**, built by **Armclang**. |
| |
| .. code-block:: bash |
| |
| cd <TFM root dir> |
| mkdir build && cd build |
| cmake -DTFM_PLATFORM=arm/mps2/an521 \ |
| -DTFM_TOOLCHAIN_FILE=../toolchain_ARMCLANG.cmake \ |
| -DTFM_PROFILE=profile_small \ |
| -DCMAKE_BUILD_TYPE=MinSizeRel \ |
| ../ |
| cmake --build ./ -- install |
| |
| The following commands build Profile Small with regression test cases on **AN521** |
| with build type **MinSizeRel**, built by **Armclang**. |
| |
| .. code-block:: bash |
| |
| cd <TFM root dir> |
| mkdir build && cd build |
| cmake -DTFM_PLATFORM=arm/mps2/an521 \ |
| -DTFM_TOOLCHAIN_FILE=../toolchain_ARMCLANG.cmake \ |
| -DTFM_PROFILE=profile_small \ |
| -DCMAKE_BUILD_TYPE=MinSizeRel \ |
| -DTEST_S=ON -DTEST_NS=ON \ |
| ../ |
| cmake --build ./ -- install |
| |
| .. Note:: |
| |
| - For devices with more contrained memory and flash requirements, it is |
| possible to build with either only TEST_S enabled or only TEST_NS enabled. |
| This will decrease the size of the test images. Note that both test suites |
| must still be run to ensure correct operation. |
| |
| More details of building instructions and parameters can be found TF-M build |
| instruction guide [11]_. |
| |
| ********* |
| Reference |
| ********* |
| |
| .. [1] `Pre-Shared Key Ciphersuites for Transport Layer Security (TLS) <https://tools.ietf.org/html/rfc4279>`_ |
| |
| .. [2] `DEN0063 Arm Platform Security Architecture Firmware Framework 1.0 <https://developer.arm.com/-/media/Files/pdf/DeviceSecurityArchitecture/Architect/DEN0063-PSA_Firmware_Framework-1.0.0-2.pdf?revision=2d1429fa-4b5b-461a-a60e-4ef3d8f7f4b4>`_ |
| |
| .. [3] `PSA analyze stage <https://developer.arm.com/architectures/security-architectures/platform-security-architecture#analyze>`_ |
| |
| .. [4] `AES-CCM Cipher Suites for Transport Layer Security (TLS) <https://tools.ietf.org/html/rfc6655>`_ |
| |
| .. [5] `Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms <https://tools.ietf.org/html/rfc6151>`_ |
| |
| .. [6] `Transitioning the Use of Cryptographic Algorithms and Key Lengths <https://www.nist.gov/publications/transitioning-use-cryptographic-algorithms-and-key-lengths>`_ |
| |
| .. [7] :doc:`ITS integration guide </docs/integration_guide/services/tfm_its_integration_guide>` |
| |
| .. [8] `PSA Attestation API 1.0 (ARM IHI 0085) <https://developer.arm.com/-/media/Files/pdf/PlatformSecurityArchitecture/Implement/IHI0085-PSA_Attestation_API-1.0.2.pdf?revision=eef78753-c77e-4b24-bcf0-65596213b4c1&la=en&hash=E5E0353D612077AFDCE3F2F3708A50C77A74B2A3>`_ |
| |
| .. [9] :doc:`Secure boot </docs/technical_references/tfm_secure_boot>` |
| |
| .. [10] :doc:`Crypto design </docs/technical_references/tfm_crypto_design>` |
| |
| .. [11] :doc:`TF-M build instruction </docs/getting_started/tfm_build_instruction>` |
| |
| -------------- |
| |
| *Copyright (c) 2020-2021, Arm Limited. All rights reserved.* |