File crypto_config.h

PSA crypto configuration options (set of defines)

SECTION: SECTION Cryptographic mechanism selection (PSA API)

This section sets PSA API settings.

PSA_WANT_ALG_CBC_NO_PADDING

PSA_WANT_ALG_CBC_PKCS7

PSA_WANT_ALG_CCM

PSA_WANT_ALG_CCM_STAR_NO_TAG

PSA_WANT_ALG_CMAC

PSA_WANT_ALG_CFB

PSA_WANT_ALG_CHACHA20_POLY1305

PSA_WANT_ALG_CTR

PSA_WANT_ALG_DETERMINISTIC_ECDSA

PSA_WANT_ALG_ECB_NO_PADDING

PSA_WANT_ALG_ECDH

PSA_WANT_ALG_FFDH

PSA_WANT_ALG_ECDSA

PSA_WANT_ALG_JPAKE

PSA_WANT_ALG_GCM

PSA_WANT_ALG_HKDF

PSA_WANT_ALG_HKDF_EXTRACT

PSA_WANT_ALG_HKDF_EXPAND

PSA_WANT_ALG_HMAC

PSA_WANT_ALG_MD5

PSA_WANT_ALG_OFB

PSA_WANT_ALG_PBKDF2_HMAC

PSA_WANT_ALG_PBKDF2_AES_CMAC_PRF_128

PSA_WANT_ALG_RIPEMD160

PSA_WANT_ALG_RSA_OAEP

PSA_WANT_ALG_RSA_PKCS1V15_CRYPT

PSA_WANT_ALG_RSA_PKCS1V15_SIGN

PSA_WANT_ALG_RSA_PSS

PSA_WANT_ALG_SHA_1

PSA_WANT_ALG_SHA_224

PSA_WANT_ALG_SHA_256

PSA_WANT_ALG_SHA_384

PSA_WANT_ALG_SHA_512

PSA_WANT_ALG_SHA3_224

PSA_WANT_ALG_SHA3_256

PSA_WANT_ALG_SHA3_384

PSA_WANT_ALG_SHA3_512

PSA_WANT_ALG_STREAM_CIPHER

PSA_WANT_ALG_TLS12_PRF

PSA_WANT_ALG_TLS12_PSK_TO_MS

PSA_WANT_ALG_TLS12_ECJPAKE_TO_PMS

PSA_WANT_ALG_SHAKE128

PSA_WANT_ALG_SHAKE256

PSA_WANT_ECC_BRAINPOOL_P_R1_256

PSA_WANT_ECC_BRAINPOOL_P_R1_384

PSA_WANT_ECC_BRAINPOOL_P_R1_512

PSA_WANT_ECC_MONTGOMERY_255

PSA_WANT_ECC_MONTGOMERY_448

PSA_WANT_ECC_SECP_K1_256

PSA_WANT_ECC_SECP_R1_256

PSA_WANT_ECC_SECP_R1_384

PSA_WANT_ECC_SECP_R1_521

PSA_WANT_DH_RFC7919_2048

PSA_WANT_DH_RFC7919_3072

PSA_WANT_DH_RFC7919_4096

PSA_WANT_DH_RFC7919_6144

PSA_WANT_DH_RFC7919_8192

PSA_WANT_KEY_TYPE_DERIVE

PSA_WANT_KEY_TYPE_PASSWORD

PSA_WANT_KEY_TYPE_PASSWORD_HASH

PSA_WANT_KEY_TYPE_HMAC

PSA_WANT_KEY_TYPE_AES

PSA_WANT_KEY_TYPE_ARIA

PSA_WANT_KEY_TYPE_CAMELLIA

PSA_WANT_KEY_TYPE_CHACHA20

PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY

PSA_WANT_KEY_TYPE_DH_PUBLIC_KEY

PSA_WANT_KEY_TYPE_RAW_DATA

PSA_WANT_KEY_TYPE_RSA_PUBLIC_KEY

PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_BASIC

PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_IMPORT

PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_EXPORT

PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_GENERATE

PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_DERIVE

PSA_WANT_KEY_TYPE_RSA_KEY_PAIR_BASIC

PSA_WANT_KEY_TYPE_RSA_KEY_PAIR_IMPORT

PSA_WANT_KEY_TYPE_RSA_KEY_PAIR_EXPORT

PSA_WANT_KEY_TYPE_RSA_KEY_PAIR_GENERATE

PSA_WANT_KEY_TYPE_RSA_KEY_PAIR_DERIVE

PSA_WANT_KEY_TYPE_DH_KEY_PAIR_BASIC

PSA_WANT_KEY_TYPE_DH_KEY_PAIR_IMPORT

PSA_WANT_KEY_TYPE_DH_KEY_PAIR_EXPORT

PSA_WANT_KEY_TYPE_DH_KEY_PAIR_GENERATE

PSA_WANT_KEY_TYPE_DH_KEY_PAIR_DERIVE

SECTION: Platform abstraction layer

This section sets platform specific settings.

MBEDTLS_MEMORY_BUFFER_ALLOC_C

Enable the buffer allocator implementation that makes use of a (stack) based buffer to ‘allocate’ dynamic memory. (replaces calloc() and free() calls)

Module: platform/memory_buffer_alloc.c

Requires: MBEDTLS_PLATFORM_C MBEDTLS_PLATFORM_MEMORY (to use it within Mbed TLS)

Enable this module to enable the buffer memory allocator.

MBEDTLS_FS_IO: Enable functions that use the filesystem.

MBEDTLS_HAVE_TIME

System has time.h and time(). The time does not need to be correct, only time differences are used, by contrast with MBEDTLS_HAVE_TIME_DATE

Defining MBEDTLS_HAVE_TIME allows you to specify MBEDTLS_PLATFORM_TIME_ALT, MBEDTLS_PLATFORM_TIME_MACRO, MBEDTLS_PLATFORM_TIME_TYPE_MACRO and MBEDTLS_PLATFORM_STD_TIME.

Comment if your system does not support time functions.

MBEDTLS_HAVE_TIME_DATE

System has time.h, time(), and an implementation for mbedtls_platform_gmtime_r() (see below). The time needs to be correct (not necessarily very accurate, but at least the date should be correct). This is used to verify the validity period of X.509 certificates.

Comment if your system does not have a correct clock.

Note

mbedtls_platform_gmtime_r() is an abstraction in platform_util.h that behaves similarly to the gmtime_r() function from the C standard. Refer to the documentation for mbedtls_platform_gmtime_r() for more information.

Note

It is possible to configure an implementation for mbedtls_platform_gmtime_r() at compile-time by using the macro MBEDTLS_PLATFORM_GMTIME_R_ALT.

MBEDTLS_MEMORY_DEBUG

Enable debugging of buffer allocator memory issues. Automatically prints (to stderr) all (fatal) messages on memory allocation issues. Enables function for ‘debug output’ of allocated memory.

Requires: MBEDTLS_MEMORY_BUFFER_ALLOC_C

Uncomment this macro to let the buffer allocator print out error messages.

MBEDTLS_MEMORY_BACKTRACE

Include backtrace information with each allocated block.

Requires: MBEDTLS_MEMORY_BUFFER_ALLOC_C GLIBC-compatible backtrace() and backtrace_symbols() support

Uncomment this macro to include backtrace information

MBEDTLS_PLATFORM_C

Enable the platform abstraction layer that allows you to re-assign functions like calloc(), free(), snprintf(), printf(), fprintf(), exit().

Enabling MBEDTLS_PLATFORM_C enables to use of MBEDTLS_PLATFORM_XXX_ALT or MBEDTLS_PLATFORM_XXX_MACRO directives, allowing the functions mentioned above to be specified at runtime or compile time respectively.

Module: platform/platform.c Caller: Most other .c files

This module enables abstraction of common (libc) functions.

Note

This abstraction layer must be enabled on Windows (including MSYS2) as other modules rely on it for a fixed snprintf implementation.

MBEDTLS_PLATFORM_SETBUF_ALT

MBEDTLS_PLATFORM_EXIT_ALT

MBEDTLS_PLATFORM_XXX_ALT: Uncomment a macro to let Mbed TLS support the function in the platform abstraction layer.

Example: In case you uncomment MBEDTLS_PLATFORM_PRINTF_ALT, Mbed TLS will provide a function “mbedtls_platform_set_printf()” that allows you to set an alternative printf function pointer.

All these define require MBEDTLS_PLATFORM_C to be defined!

Requires: MBEDTLS_PLATFORM_TIME_ALT requires MBEDTLS_HAVE_TIME

Uncomment a macro to enable alternate implementation of specific base platform function

Note

MBEDTLS_PLATFORM_SNPRINTF_ALT and MBEDTLS_PLATFORM_VSNPRINTF_ALT are required on some Windows C runtimes. They will be enabled automatically by build_info.h when building with older versions of MSVC or with MinGW32.

Warning

MBEDTLS_PLATFORM_XXX_ALT cannot be defined at the same time as MBEDTLS_PLATFORM_XXX_MACRO!

MBEDTLS_PLATFORM_TIME_ALT

MBEDTLS_PLATFORM_FPRINTF_ALT

MBEDTLS_PLATFORM_PRINTF_ALT

MBEDTLS_PLATFORM_SNPRINTF_ALT

MBEDTLS_PLATFORM_VSNPRINTF_ALT

MBEDTLS_PLATFORM_NV_SEED_ALT

MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT

MBEDTLS_PLATFORM_MS_TIME_ALT

MBEDTLS_PLATFORM_GMTIME_R_ALT

Uncomment the macro to let Mbed TLS use your alternate implementation of mbedtls_platform_gmtime_r(). This replaces the default implementation in platform_util.c.

gmtime() is not a thread-safe function as defined in the C standard. The library will try to use safer implementations of this function, such as gmtime_r() when available. However, if Mbed TLS cannot identify the target system, the implementation of mbedtls_platform_gmtime_r() will default to using the standard gmtime(). In this case, calls from the library to gmtime() will be guarded by the global mutex mbedtls_threading_gmtime_mutex if MBEDTLS_THREADING_C is enabled. We recommend that calls from outside the library are also guarded with this mutex to avoid race conditions. However, if the macro MBEDTLS_PLATFORM_GMTIME_R_ALT is defined, Mbed TLS will unconditionally use the implementation for mbedtls_platform_gmtime_r() supplied at compile time.

MBEDTLS_PLATFORM_MEMORY

Enable the memory allocation layer.

By default Mbed TLS uses the system-provided calloc() and free(). This allows different allocators (self-implemented or provided) to be provided to the platform abstraction layer.

Enabling MBEDTLS_PLATFORM_MEMORY without the MBEDTLS_PLATFORM_{FREE,CALLOC}_MACROs will provide “mbedtls_platform_set_calloc_free()” allowing you to set an alternative calloc() and free() function pointer at runtime.

Enabling MBEDTLS_PLATFORM_MEMORY and specifying MBEDTLS_PLATFORM_{CALLOC,FREE}_MACROs will allow you to specify the alternate function at compile time.

An overview of how the value of mbedtls_calloc is determined:

if !MBEDTLS_PLATFORM_MEMORY
- mbedtls_calloc = calloc
if MBEDTLS_PLATFORM_MEMORY
- if (MBEDTLS_PLATFORM_CALLOC_MACRO && MBEDTLS_PLATFORM_FREE_MACRO):
  - mbedtls_calloc = MBEDTLS_PLATFORM_CALLOC_MACRO
- if !(MBEDTLS_PLATFORM_CALLOC_MACRO && MBEDTLS_PLATFORM_FREE_MACRO):
  - Dynamic setup via mbedtls_platform_set_calloc_free is now possible with a default value MBEDTLS_PLATFORM_STD_CALLOC.
  - How is MBEDTLS_PLATFORM_STD_CALLOC handled?
  - if MBEDTLS_PLATFORM_NO_STD_FUNCTIONS:
    - MBEDTLS_PLATFORM_STD_CALLOC is not set to anything;
    - MBEDTLS_PLATFORM_STD_MEM_HDR can be included if present;
  - if !MBEDTLS_PLATFORM_NO_STD_FUNCTIONS:
    - if MBEDTLS_PLATFORM_STD_CALLOC is present:
      - User-defined MBEDTLS_PLATFORM_STD_CALLOC is respected;
    - if !MBEDTLS_PLATFORM_STD_CALLOC:
      - MBEDTLS_PLATFORM_STD_CALLOC = calloc
  - At this point the presence of MBEDTLS_PLATFORM_STD_CALLOC is checked.
  - if !MBEDTLS_PLATFORM_STD_CALLOC
    - MBEDTLS_PLATFORM_STD_CALLOC = uninitialized_calloc
  - mbedtls_calloc = MBEDTLS_PLATFORM_STD_CALLOC.

Defining MBEDTLS_PLATFORM_CALLOC_MACRO and MBEDTLS_PLATFORM_STD_CALLOC at the same time is not possible. MBEDTLS_PLATFORM_CALLOC_MACRO and MBEDTLS_PLATFORM_FREE_MACRO must both be defined or undefined at the same time. MBEDTLS_PLATFORM_STD_CALLOC and MBEDTLS_PLATFORM_STD_FREE do not have to be defined at the same time, as, if they are used, dynamic setup of these functions is possible. See the tree above to see how are they handled in all cases. An uninitialized MBEDTLS_PLATFORM_STD_CALLOC always fails, returning a null pointer. An uninitialized MBEDTLS_PLATFORM_STD_FREE does not do anything.

Requires: MBEDTLS_PLATFORM_C

Enable this layer to allow use of alternative memory allocators.

MBEDTLS_PLATFORM_NO_STD_FUNCTIONS

Do not assign standard functions in the platform layer (e.g. calloc() to MBEDTLS_PLATFORM_STD_CALLOC and printf() to MBEDTLS_PLATFORM_STD_PRINTF)

This makes sure there are no linking errors on platforms that do not support these functions. You will HAVE to provide alternatives, either at runtime via the platform_set_xxx() functions or at compile time by setting the MBEDTLS_PLATFORM_STD_XXX defines, or enabling a MBEDTLS_PLATFORM_XXX_MACRO.

Requires: MBEDTLS_PLATFORM_C

Uncomment to prevent default assignment of standard functions in the platform layer.

MBEDTLS_PLATFORM_ZEROIZE_ALT

Uncomment the macro to let Mbed TLS use your alternate implementation of mbedtls_platform_zeroize(), to wipe sensitive data in memory. This replaces the default implementation in platform_util.c.

By default, the library uses a system function such as memset_s() (optional feature of C11), explicit_bzero() (BSD and compatible), or SecureZeroMemory (Windows). If no such function is detected, the library falls back to a plain C implementation. Compilers are technically permitted to optimize this implementation out, meaning that the memory is not actually wiped. The library tries to prevent that, but the C language makes it impossible to guarantee that the memory will always be wiped.

If your platform provides a guaranteed method to wipe memory which platform_util.c does not detect, define this macro to the name of a function that takes two arguments, a void * pointer and a length, and wipes that many bytes starting at the specified address. For example, if your platform has explicit_bzero() but platform_util.c does not detect its presence, define MBEDTLS_PLATFORM_ZEROIZE_ALT to be explicit_bzero to use that function as mbedtls_platform_zeroize().

MBEDTLS_THREADING_ALT

Provide your own alternate implementation of threading primitives: mutexes and condition variables. If you enable this option:

Provide a header file "threading_alt.h", defining the following elements:
- The type mbedtls_platform_mutex_t of mutex objects.
- The type mbedtls_platform_condition_variable_t of condition variable objects.
Call the function mbedtls_threading_set_alt() in your application before calling any other library function (in particular before calling psa_crypto_init()).

See mbedtls/threading.h for more details, especially the documentation of mbedtls_threading_set_alt().

Requires: MBEDTLS_THREADING_C

Uncomment this to allow your own alternate threading implementation.

MBEDTLS_THREADING_PTHREAD

Enable the pthread wrapper layer for the threading layer.

Requires: MBEDTLS_THREADING_C

Uncomment this to enable pthread mutexes.

MBEDTLS_THREADING_C

Enable the threading abstraction layer.

Module: platform/threading.c

This allows different threading implementations (built-in or provided externally).

You will have to enable either MBEDTLS_THREADING_ALT or MBEDTLS_THREADING_PTHREAD.

Enable this layer to allow use of mutexes within Mbed TLS

Note

You must enable this option if TF-PSA-Crypto runs in a multithreaded environment. Otherwise the PSA cryptography subsystem is not thread-safe. As an exception, this option can be disabled if all PSA crypto functions are ever called from a single thread. Note that this includes indirect calls, for example through PK.

MBEDTLS_MEMORY_ALIGN_MULTIPLE: Align on multiples of this value

MBEDTLS_PLATFORM_CALLOC_MACRO: Default allocator macro to use, can be undefined. See MBEDTLS_PLATFORM_STD_CALLOC for requirements.

MBEDTLS_PLATFORM_EXIT_MACRO: Default exit macro to use, can be undefined

MBEDTLS_PLATFORM_FREE_MACRO: Default free macro to use, can be undefined. See MBEDTLS_PLATFORM_STD_FREE for requirements.

MBEDTLS_PLATFORM_FPRINTF_MACRO: Default fprintf macro to use, can be undefined

MBEDTLS_PLATFORM_MS_TIME_TYPE_MACRO

MBEDTLS_PLATFORM_NV_SEED_READ_MACRO: Default nv_seed_read function to use, can be undefined

MBEDTLS_PLATFORM_NV_SEED_WRITE_MACRO: Default nv_seed_write function to use, can be undefined

MBEDTLS_PLATFORM_PRINTF_MACRO: Default printf macro to use, can be undefined

MBEDTLS_PLATFORM_SETBUF_MACRO: Default setbuf macro to use, can be undefined

MBEDTLS_PLATFORM_SNPRINTF_MACRO: Default snprintf macro to use, can be undefined

MBEDTLS_PLATFORM_STD_CALLOC: Default allocator to use, can be undefined. It must initialize the allocated buffer memory to zeroes. The size of the buffer is the product of the two parameters. The calloc function returns either a null pointer or a pointer to the allocated space. If the product is 0, the function may either return NULL or a valid pointer to an array of size 0 which is a valid input to the deallocation function. An uninitialized MBEDTLS_PLATFORM_STD_CALLOC always fails, returning a null pointer. See the description of MBEDTLS_PLATFORM_MEMORY for more details. The corresponding deallocation function is MBEDTLS_PLATFORM_STD_FREE.

MBEDTLS_PLATFORM_STD_EXIT: Default exit to use, can be undefined

MBEDTLS_PLATFORM_STD_EXIT_FAILURE: Default exit value to use, can be undefined

MBEDTLS_PLATFORM_STD_EXIT_SUCCESS: Default exit value to use, can be undefined

MBEDTLS_PLATFORM_STD_FPRINTF: Default fprintf to use, can be undefined

MBEDTLS_PLATFORM_STD_FREE: Default free to use, can be undefined. NULL is a valid parameter, and the function must do nothing. A non-null parameter will always be a pointer previously returned by MBEDTLS_PLATFORM_STD_CALLOC and not yet freed. An uninitialized MBEDTLS_PLATFORM_STD_FREE does not do anything. See the description of MBEDTLS_PLATFORM_MEMORY for more details (same principles as for MBEDTLS_PLATFORM_STD_CALLOC apply).

MBEDTLS_PLATFORM_STD_MEM_HDR: Header to include if MBEDTLS_PLATFORM_NO_STD_FUNCTIONS is defined. Don’t define if no header is needed.

MBEDTLS_PLATFORM_STD_NV_SEED_FILE: Seed file to read/write with default implementation

MBEDTLS_PLATFORM_STD_NV_SEED_READ: Default nv_seed_read function to use, can be undefined

MBEDTLS_PLATFORM_STD_NV_SEED_WRITE: Default nv_seed_write function to use, can be undefined

MBEDTLS_PLATFORM_STD_PRINTF: Default printf to use, can be undefined

MBEDTLS_PLATFORM_STD_SETBUF: Default setbuf to use, can be undefined

MBEDTLS_PLATFORM_STD_SNPRINTF: Default snprintf to use, can be undefined

MBEDTLS_PLATFORM_STD_TIME: Default time to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled

MBEDTLS_PLATFORM_TIME_MACRO: Default time macro to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled

MBEDTLS_PLATFORM_TIME_TYPE_MACRO: Default time macro to use, can be undefined. MBEDTLS_HAVE_TIME must be enabled

MBEDTLS_PLATFORM_VSNPRINTF_MACRO: Default vsnprintf macro to use, can be undefined

MBEDTLS_PRINTF_MS_TIME: Default fmt for printf. That’s avoid compiler warning if mbedtls_ms_time_t is redefined

MBEDTLS_PLATFORM_DEV_RANDOM

Path to a special file that returns cryptographic-quality random bytes when read. This is used by the default platform entropy source on non-Windows platforms unless a dedicated system call is available (see MBEDTLS_PSA_BUILTIN_GET_ENTROPY).

The default value is /dev/random, which is suitable on most platforms other than Linux. On Linux, either /dev/random or /dev/urandom may be the right choice, depending on the circumstances:

If possible, the library will use the getrandom() system call, which is preferable, and MBEDTLS_PLATFORM_DEV_RANDOM is not used.
If there is a dedicated hardware entropy source (e.g. RDRAND on x86 processors), then both /dev/random and /dev/urandom are fine.
/dev/random is always secure. However, with kernels older than 5.6, /dev/random often blocks unnecessarily if there is no dedicated hardware entropy source.
/dev/urandom never blocks. However, it may return predictable data if it is used early after the kernel boots, especially on embedded devices without an interactive user.

Thus you should change the value to /dev/urandom if your application definitely won’t be used on a device running Linux without a dedicated entropy source early during or after boot.

This is the default value of mbedtls_platform_dev_random, which can be changed at run time.

SECTION: General and test configuration options

This section sets test specific settings.

MBEDTLS_CHECK_RETURN_WARNING

If this macro is defined, emit a compile-time warning if application code calls a function without checking its return value, but the return value should generally be checked in portable applications.

This is only supported on platforms where MBEDTLS_CHECK_RETURN is implemented. Otherwise this option has no effect.

Uncomment to get warnings on using fallible functions without checking their return value.

Note

This feature is a work in progress. Warnings will be added to more functions in the future.

Note

A few functions are considered critical, and ignoring the return value of these functions will trigger a warning even if this macro is not defined. To completely disable return value check warnings, define MBEDTLS_CHECK_RETURN with an empty expansion.

MBEDTLS_DEPRECATED_WARNING

Mark deprecated functions and features so that they generate a warning if used. Functionality deprecated in one version will usually be removed in the next version. You can enable this to help you prepare the transition to a new major version by making sure your code is not using this functionality.

This only works with GCC and Clang. With other compilers, you may want to use MBEDTLS_DEPRECATED_REMOVED

Uncomment to get warnings on using deprecated functions and features.

MBEDTLS_DEPRECATED_REMOVED

Remove deprecated functions and features so that they generate an error if used. Functionality deprecated in one version will usually be removed in the next version. You can enable this to help you prepare the transition to a new major version by making sure your code is not using this functionality.

Uncomment to get errors on using deprecated functions and features.

MBEDTLS_CHECK_RETURN

This macro is used at the beginning of the declaration of a function to indicate that its return value should be checked. It should instruct the compiler to emit a warning or an error if the function is called without checking its return value.

There is a default implementation for popular compilers in platform_util.h. You can override the default implementation by defining your own here.

If the implementation here is empty, this will effectively disable the checking of functions’ return values.

MBEDTLS_IGNORE_RETURN(result)

Call this macro with one argument, a function call, to suppress a warning from MBEDTLS_CHECK_RETURN due to that function call.

This macro requires one argument, which should be a C function call. If that function call would cause a MBEDTLS_CHECK_RETURN warning, this warning is suppressed.

TF_PSA_CRYPTO_CONFIG_FILE

If defined, this is a header which will be included instead of "psa/crypto_config.h". This header file specifies which cryptographic mechanisms are available through the PSA API.

This macro is expanded after an #include directive. This is a popular but non-standard feature of the C language, so this feature is only available with compilers that perform macro expansion on an #include line.

The value of this symbol is typically a path in double quotes, either absolute or relative to a directory on the include search path.

TF_PSA_CRYPTO_USER_CONFIG_FILE

If defined, this is a header which will be included after "psa/crypto_config.h" or TF_PSA_CRYPTO_CONFIG_FILE. This allows you to modify the default configuration, including the ability to undefine options that are enabled by default.

This macro is expanded after an #include directive. This is a popular but non-standard feature of the C language, so this feature is only available with compilers that perform macro expansion on an #include line.

The value of this symbol is typically a path in double quotes, either absolute or relative to a directory on the include search path.

MBEDTLS_SELF_TEST: Enable the checkup functions (*_self_test).

MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN

Enable testing of the constant-flow nature of some sensitive functions with clang’s MemorySanitizer. This causes some existing tests to also test this non-functional property of the code under test.

This setting requires compiling with clang -fsanitize=memory. The test suites can then be run normally.

Uncomment to enable testing of the constant-flow nature of selected code.

Warning

This macro is only used for extended testing; it is not considered part of the library’s API, so it may change or disappear at any time.

MBEDTLS_TEST_CONSTANT_FLOW_VALGRIND

Enable testing of the constant-flow nature of some sensitive functions with valgrind’s memcheck tool. This causes some existing tests to also test this non-functional property of the code under test.

This setting requires valgrind headers for building, and is only useful for testing if the tests suites are run with valgrind’s memcheck. This can be done for an individual test suite with ‘valgrind ./test_suite_xxx’, or when using CMake, this can be done for all test suites with ‘make memcheck’.

Uncomment to enable testing of the constant-flow nature of selected code.

Warning

This macro is only used for extended testing; it is not considered part of the library’s API, so it may change or disappear at any time.

MBEDTLS_TEST_HOOKS

Enable features for invasive testing such as introspection functions and hooks for fault injection. This enables additional unit tests.

Merely enabling this feature should not change the behavior of the product. It only adds new code, and new branching points where the default behavior is the same as when this feature is disabled. However, this feature increases the attack surface: there is an added risk of vulnerabilities, and more gadgets that can make exploits easier. Therefore this feature must never be enabled in production.

See docs/architecture/testing/mbed-crypto-invasive-testing.md for more information.

Uncomment to enable invasive tests.

TF_PSA_CRYPTO_VERSION

Enable run-time version information.

This option enables functions for getting the version of TF-PSA-Crypto at runtime defined in include/tf-psa-crypto/version.h.

SECTION: Cryptographic mechanism selection (extended API)

This section sets cryptographic mechanism settings.

MBEDTLS_LMS_C

Enable the LMS stateful-hash asymmetric signature algorithm.

Module: extras/lms.c Caller:

Requires: MBEDTLS_PSA_CRYPTO_C

Uncomment to enable the LMS verification algorithm and public key operations.

MBEDTLS_LMS_PRIVATE

Enable LMS private-key operations and signing code. Functions enabled by this option are experimental, and should not be used in production.

Requires: MBEDTLS_LMS_C

Uncomment to enable the LMS signature algorithm and private key operations.

MBEDTLS_MD_C

Enable the generic layer for message digest (hashing).

Requires: MBEDTLS_PSA_CRYPTO_C with at least one hash. Module: extras/md.c Caller: drivers/builtin/src/ecdsa.c drivers/builtin/src/ecjpake.c drivers/builtin/src/hmac_drbg.c drivers/builtin/src/psa_crypto_ecp.c drivers/builtin/src/psa_crypto_rsa.c drivers/builtin/src/rsa.c extras/pk.c utilities/constant_time.c utilities/pkcs5.c

Uncomment to enable generic message digest wrappers.

MBEDTLS_NIST_KW_C

Enable the 128-bit key wrapping modes from NIST SP 800-38F: KW (also known as RFC 3394) and KWP (RFC 5649). Currently these modes are only supported with AES.

Module: extras/nist_kw.c

Auto enables: PSA_WANT_ALG_ECB_NO_PADDING

MBEDTLS_PK_C

Enable the generic public (asymmetric) key layer.

Module: extras/pk.c Caller: drivers/builtin/src/psa_crypto_rsa.c

Requires: MBEDTLS_PSA_CRYPTO_CLIENT and at least one between PSA_WANT_KEY_TYPE_RSA_PUBLIC_KEY and PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY.

Uncomment to enable generic public key wrappers.

MBEDTLS_PKCS5_C

Enable PKCS#5 functions.

Module: utilities/pkcs5.c

Auto-enables: MBEDTLS_MD_C

This module adds support for the PKCS#5 functions.

MBEDTLS_PK_PARSE_C

Enable the generic public (asymmetric) key parser.

Module: extras/pkparse.c

Requires: MBEDTLS_ASN1_PARSE_C, MBEDTLS_PK_C

Uncomment to enable generic public key parse functions.

MBEDTLS_PK_PARSE_EC_EXTENDED

Enhance support for reading EC keys using variants of SEC1 not allowed by RFC 5915 and RFC 5480.

Currently this means parsing the SpecifiedECDomain choice of EC parameters (only known groups are supported, not arbitrary domains, to avoid validation issues).

Disable if you only need to support RFC 5915 + 5480 key formats.

MBEDTLS_PK_PARSE_EC_COMPRESSED: Enable the support for parsing public keys of type Short Weierstrass (PSA_ECC_FAMILY_SECP_XXX and PSA_ECC_FAMILY_BRAINPOOL_XXX) which are using the compressed point format.

MBEDTLS_PK_WRITE_C

Enable the generic public (asymmetric) key writer.

Module: extras/pkwrite.c

Requires: MBEDTLS_ASN1_WRITE_C, MBEDTLS_PK_C

Uncomment to enable generic public key write functions.

SECTION: Data format support

This section sets data-format specific settings.

MBEDTLS_ASN1_PARSE_C

Enable the generic ASN1 parser.

Module: utilities/asn1parse.c Caller: extras/pkparse.c utilities/pkcs5.c

MBEDTLS_ASN1_WRITE_C

Enable the generic ASN1 writer.

Module: utilities/asn1write.c Caller: drivers/builtin/src/ecdsa.c extras/pkwrite.c

MBEDTLS_BASE64_C

Enable the Base64 module.

Module: utilities/base64.c Caller: utilities/pem.c

This module is required for PEM support (required by X.509).

MBEDTLS_PEM_PARSE_C

Enable PEM decoding / parsing.

Module: utilities/pem.c Caller: extras/pkparse.c

Requires: MBEDTLS_BASE64_C optionally PSA_WANT_ALG_MD5

This modules adds support for decoding / parsing PEM files.

MBEDTLS_PEM_WRITE_C

Enable PEM encoding / writing.

Module: utilities/pem.c Caller: extras/pkwrite.c

Requires: MBEDTLS_BASE64_C

This modules adds support for encoding / writing PEM files.

SECTION: PSA core

This section sets PSA specific settings.

MBEDTLS_CTR_DRBG_C

Enable the CTR_DRBG AES-based random generator. The CTR_DRBG generator uses AES-256 by default. To use AES-128 instead, set MBEDTLS_PSA_CRYPTO_RNG_STRENGTH to 128.

AES support can either be achieved through built-in AES or PSA. Built-in is the default option when present otherwise PSA is used.

Module: drivers/builtin/src/ctr_drbg.c

Requires: MBEDTLS_PSA_CRYPTO_C, PSA_WANT_KEY_TYPE_AES and PSA_WANT_ALG_ECB_NO_PADDING

This module provides the CTR_DRBG AES random number generator.

MBEDTLS_ENTROPY_NO_SOURCES_OK

Normally, TF-PSA-Crypto requires at least one “true” entropy source, such MBEDTLS_PSA_BUILTIN_GET_ENTROPY or MBEDTLS_PSA_DRIVER_GET_ENTROPY.

It is possible to build the library with a seed injected during device provisioning, thanks to MBEDTLS_ENTROPY_NV_SEED. This is only an initial entropy input: without a true entropy source, the device will not obtain additional entropy during its lifetime. Thus, if the seed value is leaked, it is impossible to recover from this compromise.

Enable this option if this loss of security is acceptable to you.

MBEDTLS_ENTROPY_NV_SEED

Enable the non-volatile (NV) seed file-based entropy source. (Also enables the NV seed read/write functions in the platform layer)

This is crucial (if not required) on systems that do not have a cryptographic entropy source (in hardware or kernel) available.

Requires: MBEDTLS_PSA_CRYPTO_C, !MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG MBEDTLS_PLATFORM_C

Note

The read/write functions that are used by the entropy source are determined in the platform layer, and can be modified at runtime and/or compile-time depending on the flags (MBEDTLS_PLATFORM_NV_SEED_*) used.

Note

If you use the default implementation functions that read a seedfile with regular fopen(), please make sure you make a seedfile with the proper name (defined in MBEDTLS_PLATFORM_STD_NV_SEED_FILE) and at least MBEDTLS_ENTROPY_BLOCK_SIZE bytes in size that can be read from and written to or you will get an entropy source error! The default implementation will only use the first MBEDTLS_ENTROPY_BLOCK_SIZE bytes from the file.

Note

The entropy collector will write to the seed file before entropy is given to an external source, to update it.

MBEDTLS_HMAC_DRBG_C

Enable the HMAC_DRBG random generator.

Module: drivers/builtin/src/hmac_drbg.c Caller:

Requires: MBEDTLS_MD_C

Uncomment to enable the HMAC_DRBG random number generator.

MBEDTLS_PSA_CRYPTO_C

Enable the Platform Security Architecture cryptography API.

Module: core/psa_crypto.c

Requires: one of the following:

MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG
MBEDTLS_CTR_DRBG_C
MBEDTLS_HMAC_DRBG_C

If MBEDTLS_CTR_DRBG_C or MBEDTLS_HMAC_DRBG_C is used as the PSA random generator, then either PSA_WANT_ALG_SHA_256 or PSA_WANT_ALG_SHA_512 must be enabled for the entropy module.

A future version may reevaluate the prioritization of DRBG mechanisms.

Note

The PSA crypto subsystem prioritizes DRBG mechanisms as follows:

MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG, if enabled
CTR_DRBG (AES), seeded by the entropy module, if MBEDTLS_CTR_DRBG_C is enabled
HMAC_DRBG, seeded by the entropy module, if MBEDTLS_HMAC_DRBG_C is enabled

MBEDTLS_PSA_ASSUME_EXCLUSIVE_BUFFERS

Assume all buffers passed to PSA functions are owned exclusively by the PSA function and are not stored in shared memory.

This option may be enabled if all buffers passed to any PSA function reside in memory that is accessible only to the PSA function during its execution.

This option MUST be disabled whenever buffer arguments are in memory shared with an untrusted party, for example where arguments to PSA calls are passed across a trust boundary.

Note

Enabling this option reduces memory usage and code size.

Note

Enabling this option causes overlap of input and output buffers not to be supported by PSA functions.

MBEDTLS_PSA_BUILTIN_GET_ENTROPY

Enable entropy sources for which the library has a built-in driver.

Requires: MBEDTLS_PSA_CRYPTO_C, !MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG

These are:

getrandom() on Linux (if syscall() is available at compile time);
getrandom() on FreeBSD and DragonFlyBSD (if available at compile time);
sysctl(KERN_ARND) on FreeBSD and NetBSD;
MBEDTLS_PLATFORM_DEV_RANDOM on Unix-like platforms (unless one of the above is used);
BCryptGenRandom() on Windows.

You should enable this option if your platform has one of these. If not:

You can enable MBEDTLS_PSA_DRIVER_GET_ENTROPY instead, and provide an entropy source callback for your platform.
If your platform has a fast cryptographic-quality random generator, enable MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG and provide a random generator callback instead.
If your platform has no source of entropy at all, you can enable MBEDTLS_ENTROPY_NV_SEED and provide a seed in nonvolatile memory during the provisioning of the device.
The random generator requires a random generator callback, an entropy source or a seed in nonvolatile memory. Builds with no random generator are not officially supported yet, except client-only builds (MBEDTLS_PSA_CRYPTO_CLIENT enabled and MBEDTLS_PSA_CRYPTO_C disabled).

MBEDTLS_PSA_CRYPTO_BUILTIN_KEYS

Enable support for platform built-in keys. If you enable this feature, you must implement the function mbedtls_psa_platform_get_builtin_key(). See the documentation of that function for more information.

Built-in keys are typically derived from a hardware unique key or stored in a secure element.

Requires: MBEDTLS_PSA_CRYPTO_C.

Warning

This interface is experimental and may change or be removed without notice.

MBEDTLS_PSA_CRYPTO_CLIENT: Enable support for PSA crypto client.

Note

This option allows to include the code necessary for a PSA crypto client when the PSA crypto implementation is not included in the library (MBEDTLS_PSA_CRYPTO_C disabled). The code included is the code to set and get PSA key attributes. The development of PSA drivers partially relying on the library to fulfill the hardware gaps is another possible usage of this option.

Warning

This interface is experimental and may change or be removed without notice.

MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG

Make the PSA Crypto module use an external random generator provided by a driver, instead of Mbed TLS’s entropy and DRBG modules.

If you enable this option, you must configure the type mbedtls_psa_external_random_context_t in psa/crypto_platform.h and define a function called mbedtls_psa_external_get_random() with the following prototype:

psa_status_t mbedtls_psa_external_get_random(
    mbedtls_psa_external_random_context_t *context,
    uint8_t *output, size_t output_size, size_t *output_length);
);

The context value is initialized to 0 before the first call. The function must fill the output buffer with output_size bytes of random data and set *output_length to output_size.

Requires: MBEDTLS_PSA_CRYPTO_C

Note

This random generator must deliver random numbers with cryptographic quality and high performance. It must supply unpredictable numbers with a uniform distribution. The implementation of this function is responsible for ensuring that the random generator is seeded with sufficient entropy. If you have a hardware TRNG which is slow or delivers non-uniform output, declare it as an entropy source with mbedtls_entropy_add_source() instead of enabling this option.

Note

This option is experimental and may be removed without notice.

Warning

If you enable this option, code that uses the PSA cryptography interface will not use any of the entropy sources set up for the entropy module, nor the NV seed that MBEDTLS_ENTROPY_NV_SEED enables.

MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER

MBEDTLS_PSA_CRYPTO_SPM

When MBEDTLS_PSA_CRYPTO_SPM is defined, the code is built for SPM (Secure Partition Manager) integration which separates the code into two parts: a NSPE (Non-Secure Process Environment) and an SPE (Secure Process Environment).

If you enable this option, your build environment must include a header file "crypto_spe.h" (either in the psa subdirectory of the Mbed TLS header files, or in another directory on the compiler’s include search path). Alternatively, your platform may customize the header psa/crypto_platform.h, in which case it can skip or replace the inclusion of "crypto_spe.h".

Module: core/psa_crypto.c Requires: MBEDTLS_PSA_CRYPTO_C

MBEDTLS_PSA_CRYPTO_STORAGE_C

Enable the Platform Security Architecture persistent key storage.

Module: core/psa_crypto_storage.c

Requires: MBEDTLS_PSA_CRYPTO_C, either MBEDTLS_PSA_ITS_FILE_C or a native implementation of the PSA ITS interface

MBEDTLS_PSA_DRIVER_GET_ENTROPY

Requires: MBEDTLS_PSA_CRYPTO_C, !MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG

Enable the custom entropy callback mbedtls_platform_get_entropy() (declared in mbedtls/platform.h). You need to provide this callback if you need an entropy source and the built-in entropy callback provided by MBEDTLS_PSA_BUILTIN_GET_ENTROPY does not work on your platform.

Enabling both MBEDTLS_PSA_BUILTIN_GET_ENTROPY and MBEDTLS_PSA_DRIVER_GET_ENTROPY is currently not supported.

You do not need any entropy source in the following circumstances:

If your platform has a fast cryptographic-quality random generator, and you enable MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG and provide a random generator callback instead.
If your platform has no source of entropy at all, and you enable MBEDTLS_ENTROPY_NV_SEED and provide a seed in nonvolatile memory during the provisioning of the device.
If you build the library with no random generator. Builds with no random generator are not officially supported yet, except client-only builds (MBEDTLS_PSA_CRYPTO_CLIENT enabled and MBEDTLS_PSA_CRYPTO_C disabled).

MBEDTLS_PSA_ITS_FILE_C

Enable the emulation of the Platform Security Architecture Internal Trusted Storage (PSA ITS) over files.

Module: core/psa_its_file.c

Requires: MBEDTLS_FS_IO

MBEDTLS_PSA_KEY_STORE_DYNAMIC

Dynamically resize the PSA key store to accommodate any number of volatile keys (until the heap memory is exhausted).

If this option is disabled, the key store has a fixed size MBEDTLS_PSA_KEY_SLOT_COUNT for volatile keys and loaded persistent keys together.

This option has no effect when MBEDTLS_PSA_CRYPTO_C is disabled.

Module: core/psa_crypto.c Requires: MBEDTLS_PSA_CRYPTO_C

MBEDTLS_PSA_STATIC_KEY_SLOTS

Statically preallocate memory to store keys’ material in PSA instead of allocating it dynamically when required. This allows builds without a heap, if none of the enabled cryptographic implementations or other features require it. This feature affects both volatile and persistent keys which means that it’s not possible to persistently store a key which is larger than MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE.

Requires: MBEDTLS_PSA_CRYPTO_C

Note

This feature comes with a (potentially) higher RAM usage since:

All the key slots are allocated no matter if they are used or not.
Each key buffer’s length is MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE bytes.

MBEDTLS_PSA_CRYPTO_PLATFORM_FILE

If defined, this is a header which will be included instead of "psa/crypto_platform.h". This file should declare the same identifiers as the one in Mbed TLS, but with definitions adapted to the platform on which the library code will run.

This macro is expanded after an #include directive. This is a popular but non-standard feature of the C language, so this feature is only available with compilers that perform macro expansion on an #include line.

The value of this symbol is typically a path in double quotes, either absolute or relative to a directory on the include search path.

Note

The required content of this header can vary from one version of Mbed TLS to the next. Integrators who provide an alternative file should review the changes in the original file whenever they upgrade Mbed TLS.

MBEDTLS_PSA_CRYPTO_STRUCT_FILE

If defined, this is a header which will be included instead of "psa/crypto_struct.h". This file should declare the same identifiers as the one in Mbed TLS, but with definitions adapted to the environment in which the library code will run. The typical use for this feature is to provide alternative type definitions on the client side in client-server integrations of PSA crypto, where operation structures contain handles instead of cryptographic data.

This macro is expanded after an #include directive. This is a popular but non-standard feature of the C language, so this feature is only available with compilers that perform macro expansion on an #include line.

The value of this symbol is typically a path in double quotes, either absolute or relative to a directory on the include search path.

Note

The required content of this header can vary from one version of Mbed TLS to the next. Integrators who provide an alternative file should review the changes in the original file whenever they upgrade Mbed TLS.

MBEDTLS_PSA_KEY_SLOT_COUNT

When MBEDTLS_PSA_KEY_STORE_DYNAMIC is disabled, the maximum amount of PSA keys simultaneously in memory. This counts all volatile keys, plus loaded persistent keys.

When MBEDTLS_PSA_KEY_STORE_DYNAMIC is enabled, the maximum number of loaded persistent keys.

Currently, persistent keys do not need to be loaded all the time while a multipart operation is in progress, only while the operation is being set up. This may change in future versions of the library.

Currently, the library traverses of the whole table on each access to a persistent key. Therefore large values may cause poor performance.

This option has no effect when MBEDTLS_PSA_CRYPTO_C is disabled.

MBEDTLS_PSA_STATIC_KEY_SLOT_BUFFER_SIZE: Define the size (in bytes) of each static key buffer when MBEDTLS_PSA_STATIC_KEY_SLOTS is set. If not explicitly defined then it’s automatically guessed from available PSA keys enabled in the build through PSA_WANT_xxx symbols. If required by the application this parameter can be set to higher values in order to store larger objects (ex: raw keys), but please note that this will increase RAM usage.

MBEDTLS_PSA_CRYPTO_RNG_STRENGTH: Minimum security strength (in bits) of the PSA RNG.

Note

Valid values: 128 or default of 256.

MBEDTLS_PSA_CRYPTO_RNG_HASH

Hash algorithm to use for the entropy module and for HMAC_DRBG if configured.

The hash size (in bits) must be at least MBEDTLS_PSA_CRYPTO_RNG_STRENGTH.

In addition, if the entropy module is enabled (MBEDTLS_PSA_CRYPTO_C is enabled and MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG is disabled):

The hash size must be at least 32 bytes (i.e., 256 bits).
Only two values are currently allowed: PSA_ALG_SHA_256 and PSA_ALG_SHA_512. A future version may lift this limitation.

If MBEDTLS_PSA_CRYPTO_RNG_HASH is not explicitly set in the configuration, a default hash that satisfies the above constraints is selected automatically. If no suitable default can be selected, this will result in a build error.

MBEDTLS_PSA_RNG_RESEED_INTERVAL: In CTR_DRBG and HMAC_DRBG, the interval before the DRBG is reseeded from entropy. The interval is the number of requests to the random generator, for any purpose.

Note

Requests have a maximum size (which depends on the library configuration and is currently unspecified), so the maximum number of bytes before a reseed is the interval multiplied by the maximum request size.

SECTION: Builtin drivers

This section sets driver specific settings.

MBEDTLS_AESNI_C

Enable AES-NI support on x86-64 or x86-32.

Module: drivers/builtin/src/aesni.c Caller: drivers/builtin/src/aes.c

Requires: MBEDTLS_HAVE_ASM (on some platforms, see note)

This modules adds support for the AES-NI instructions on x86.

Note

AESNI is only supported with certain compilers and target options:

Visual Studio: supported
GCC, x86-64, target not explicitly supporting AESNI: requires MBEDTLS_HAVE_ASM.
GCC, x86-32, target not explicitly supporting AESNI: not supported.
GCC, x86-64 or x86-32, target supporting AESNI: supported. For this assembly-less implementation, you must currently compile drivers/builtin/src/aesni.c and drivers/builtin/src/aes.c with machine options to enable SSE2 and AESNI instructions: gcc -msse2 -maes -mpclmul or clang -maes -mpclmul.
Non-x86 targets: this option is silently ignored.
Other compilers: this option is silently ignored.

Note

Above, “GCC” includes compatible compilers such as Clang. The limitations on target support are likely to be relaxed in the future.

MBEDTLS_AESCE_C

Enable AES cryptographic extension support on Armv8.

Module: drivers/builtin/src/aesce.c Caller: drivers/builtin/src/aes.c

Requires: The AES built-in implementation

This module adds support for the AES Armv8-A Cryptographic Extensions on Armv8 systems.

Note

Minimum compiler versions for this feature when targeting aarch64 are Clang 4.0; armclang 6.6; GCC 6.0; or MSVC 2019 version 16.11.2. Minimum compiler versions for this feature when targeting 32-bit Arm or Thumb are Clang 11.0; armclang 6.20; or GCC 6.0.

Note

CFLAGS must be set to a minimum of -march=armv8-a+crypto for armclang <= 6.9

Warning

Runtime detection only works on Linux. For non-Linux operating system, Armv8-A Cryptographic Extensions must be supported by the CPU when this option is enabled.

MBEDTLS_AES_ROM_TABLES

Use precomputed AES tables stored in ROM.

Uncomment this macro to use precomputed AES tables stored in ROM. Comment this macro to generate AES tables in RAM at runtime.

Tradeoff: Using precomputed ROM tables reduces RAM usage by ~8kb (or ~2kb if MBEDTLS_AES_FEWER_TABLES is used) and reduces the initialization time before the first AES operation can be performed. It comes at the cost of additional ~8kb ROM use (resp. ~2kb if MBEDTLS_AES_FEWER_TABLES below is used), and potentially degraded performance if ROM access is slower than RAM access.

This option is independent of MBEDTLS_AES_FEWER_TABLES.

MBEDTLS_AES_FEWER_TABLES

Use less ROM/RAM for AES tables.

Uncommenting this macro omits 75% of the AES tables from ROM / RAM (depending on the value of MBEDTLS_AES_ROM_TABLES) by computing their values on the fly during operations (the tables are entry-wise rotations of one another).

Tradeoff: Uncommenting this reduces the RAM / ROM footprint by ~6kb but at the cost of more arithmetic operations during runtime. Specifically, one has to compare 4 accesses within different tables to 4 accesses with additional arithmetic operations within the same table. The performance gain/loss depends on the system and memory details.

This option is independent of MBEDTLS_AES_ROM_TABLES.

MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH

Use only 128-bit keys in AES operations to save ROM.

Uncomment this macro to remove support for AES operations that use 192- or 256-bit keys.

Uncommenting this macro reduces the size of AES code by ~300 bytes on v8-M/Thumb2.

Module: drivers/builtin/src/aes.c

Requires: The AES built-in implementation

MBEDTLS_AES_USE_HARDWARE_ONLY

MBEDTLS_BLOCK_CIPHER_NO_DECRYPT

Remove decryption operation for AES, ARIA and Camellia block cipher.

Module: drivers/builtin/src/aes.c drivers/builtin/src/aesce.c drivers/builtin/src/aesni.c drivers/builtin/src/aria.c drivers/builtin/src/camellia.c drivers/builtin/src/cipher.c

Note

This feature is incompatible with PSA_WANT_ALG_ECB_NO_PADDING, PSA_WANT_ALG_CBC_NO_PADDING, PSA_WANT_ALG_CBC_PKCS7 and MBEDTLS_NIST_KW_C.

MBEDTLS_CAMELLIA_SMALL_MEMORY

Use less ROM for the Camellia implementation (saves about 768 bytes).

Uncomment this macro to use less memory for Camellia.

MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED

Enable the verified implementations of ECDH primitives from Project Everest (currently only Curve25519).

The Everest code is provided under the Apache 2.0 license only; therefore enabling this option is not compatible with taking the library under the GPL v2.0-or-later license.

MBEDTLS_ECP_NIST_OPTIM

Enable specific ‘modulo p’ routines for each NIST prime. Depending on the prime and architecture, makes operations 4 to 8 times faster on the corresponding curve.

Comment this macro to disable NIST curves optimisation.

MBEDTLS_ECP_RESTARTABLE

Enable “non-blocking” ECC operations that can return early and be resumed.

This allows various functions to pause by returning PSA_OPERATION_INCOMPLETE and then be called later again in order to further progress and eventually complete their operation. This is controlled through psa_interruptible_set_max_ops() which limits the maximum number of ECC operations a function may perform before pausing; see psa_interruptible_set_max_ops() for more information.

This is useful in non-threaded environments if you want to avoid blocking for too long on ECC (and, hence, X.509 or SSL/TLS) operations.

This option:

Adds xxx_restartable() variants of existing operations in the following modules, with corresponding restart context types:
- ECP (for Short Weierstrass curves only): scalar multiplication (mul), linear combination (muladd);
- ECDSA: signature generation & verification;
- PK: signature generation & verification;
- X509: certificate chain verification.
Adds mbedtls_ecdh_enable_restart() in the ECDH module.
Changes the behaviour of TLS 1.2 clients (not servers) when using the ECDHE-ECDSA key exchange (not other key exchanges) to make all ECC computations restartable:
- verification of the server’s key exchange signature;
- verification of the server’s certificate chain;
- generation of the client’s signature if client authentication is used, with an ECC key/certificate.

Requires: Builtin support of Elliptic Curves.

Uncomment this macro to enable restartable ECC computations.

Note

When this option is enabled, restartable operations in PK, X.509 and TLS (see above) are not using PSA. On the other hand, ECDH computations in TLS are using PSA, and are not restartable. These are temporary limitations that should be lifted in the future. (See https://github.com/Mbed-TLS/mbedtls/issues/9784 and https://github.com/Mbed-TLS/mbedtls/issues/9817)

MBEDTLS_ECP_WITH_MPI_UINT: Uncomment to enable using new bignum code in the ECC modules.

Warning

This is currently experimental, incomplete and therefore should not be used in production.

MBEDTLS_GCM_LARGE_TABLE

Enable large pre-computed tables for Galois/Counter Mode (GCM). Can significantly increase throughput on systems without GCM hardware acceleration (e.g., AESNI, AESCE).

The mbedtls_gcm_context size will increase by 3840 bytes. The code size will increase by roughly 344 bytes.

Module: drivers/builtin/src/gcm.c

Requires: The GCM built-in implementation

MBEDTLS_HAVE_ASM

The compiler has support for asm().

Requires support for asm() in compiler.

Used in: drivers/builtin/src/aesni.h drivers/builtin/src/aria.c drivers/builtin/src/bn_mul.h utilities/constant_time.c

Required by: MBEDTLS_AESCE_C MBEDTLS_AESNI_C (on some platforms)

Comment to disable the use of assembly code.

MBEDTLS_HAVE_SSE2

CPU supports SSE2 instruction set.

Uncomment if the CPU supports SSE2 (IA-32 specific).

MBEDTLS_NO_UDBL_DIVISION

The platform lacks support for double-width integer division (64-bit division on a 32-bit platform, 128-bit division on a 64-bit platform).

Used in: include/mbedtls/bignum.h drivers/builtin/src/bignum.c

The bignum code uses double-width division to speed up some operations. Double-width division is often implemented in software that needs to be linked with the program. The presence of a double-width integer type is usually detected automatically through preprocessor macros, but the automatic detection cannot know whether the code needs to and can be linked with an implementation of division for that type. By default division is assumed to be usable if the type is present. Uncomment this option to prevent the use of double-width division.

Note that division for the native integer type is always required. Furthermore, a 64-bit type is always required even on a 32-bit platform, but it need not support multiplication or division. In some cases it is also desirable to disable some double-width operations. For example, if double-width division is implemented in software, disabling it can reduce code size in some embedded targets.

MBEDTLS_NO_64BIT_MULTIPLICATION

The platform lacks support for 32x32 -> 64-bit multiplication.

Used in: drivers/builtin/src/poly1305.c

Some parts of the library may use multiplication of two unsigned 32-bit operands with a 64-bit result in order to speed up computations. On some platforms, this is not available in hardware and has to be implemented in software, usually in a library provided by the toolchain.

Sometimes it is not desirable to have to link to that library. This option removes the dependency of that library on platforms that lack a hardware 64-bit multiplier by embedding a software implementation in Mbed TLS.

Note that depending on the compiler, this may decrease performance compared to using the library function provided by the toolchain.

MBEDTLS_PSA_P256M_DRIVER_ENABLED

Uncomment to enable p256-m. This is an alternative implementation of key generation, ECDH and (randomized) ECDSA on the curve SECP256R1. Compared to the default implementation:

p256-m has a much smaller code size and RAM footprint.
p256-m is only available via the PSA API. This includes the pk module.
p256-m does not support deterministic ECDSA, EC-JPAKE, custom protocols over the core arithmetic, or deterministic derivation of keys.

We recommend enabling this option if your application uses the PSA API and the only elliptic curve support it needs is ECDH and ECDSA over SECP256R1.

If you enable this option, you do not need to enable any ECC-related MBEDTLS_xxx option. You do need to separately request support for the cryptographic mechanisms through the PSA API:

MBEDTLS_PSA_CRYPTO_C for PSA-based configuration;
PSA_WANT_ECC_SECP_R1_256;
PSA_WANT_ALG_ECDH and/or PSA_WANT_ALG_ECDSA as needed;
PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY, PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_BASIC, PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_IMPORT, PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_EXPORT and/or PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_GENERATE as needed.

Note

To benefit from the smaller code size of p256-m, make sure that you do not enable any ECC-related option not supported by p256-m: this would cause the built-in ECC implementation to be built as well, in order to provide the required option. Make sure PSA_WANT_ALG_DETERMINISTIC_ECDSA, PSA_WANT_ALG_JPAKE and PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_DERIVE, and curves other than SECP256R1 are disabled as they are not supported by this driver. Also, avoid defining MBEDTLS_PK_PARSE_EC_COMPRESSED or MBEDTLS_PK_PARSE_EC_EXTENDED as those currently require a subset of the built-in ECC implementation, see docs/driver-only-builds.md.

MBEDTLS_RSA_NO_CRT

Do not use the Chinese Remainder Theorem for the RSA private operation.

Uncomment this macro to disable the use of CRT in RSA.

MBEDTLS_SHA256_SMALLER

Enable an implementation of SHA-256 that has lower ROM footprint but also lower performance.

The default implementation is meant to be a reasonable compromise between performance and size. This version optimizes more aggressively for size at the expense of performance. Eg on Cortex-M4 it reduces the size of mbedtls_sha256_process() from ~2KB to ~0.5KB for a performance hit of about 30%.

Uncomment to enable the smaller implementation of SHA256.

MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT

Enable acceleration of the SHA-256 and SHA-224 cryptographic hash algorithms with the ARMv8 cryptographic extensions if they are available at runtime. If not, the library will fall back to the C implementation.

Requires: The SHA-256 built-in implementation

Module: drivers/builtin/src/sha256.c

Uncomment to have the library check for the Armv8-A SHA-256 crypto extensions and use them if available.

Note

MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT requires the built-in SHA-256 implementation to be present in the build. This implementation is included only if PSA_WANT_ALG_SHA_256 is enabled and this results in MBEDTLS_PSA_BUILTIN_ALG_SHA_256 being defined internally (i.e., no fully-featured, fallback-free accelerator driver is present).

Note

If MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT is defined when building for a non-Armv8-A build it will be silently ignored.

Note

Minimum compiler versions for this feature are Clang 4.0, armclang 6.6 or GCC 6.0.

Note

CFLAGS must be set to a minimum of -march=armv8-a+crypto for armclang <= 6.9

Warning

MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT cannot be defined at the same time as MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY.

MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY

Enable acceleration of the SHA-256 and SHA-224 cryptographic hash algorithms with the ARMv8 cryptographic extensions, which must be available at runtime or else an illegal instruction fault will occur.

Requires: The SHA-256 built-in implementation

Module: drivers/builtin/src/sha256.c

Uncomment to have the library use the Armv8-A SHA-256 crypto extensions unconditionally.

Note

MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY requires the built-in SHA-256 implementation to be present in the build. This implementation is included only if PSA_WANT_ALG_SHA_256 is enabled and this results in MBEDTLS_PSA_BUILTIN_ALG_SHA_256 being defined internally (i.e., no fully-featured, fallback-free accelerator driver is present).

Note

This allows builds with a smaller code size than with MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT

Note

Minimum compiler versions for this feature are Clang 4.0, armclang 6.6 or GCC 6.0.

Note

CFLAGS must be set to a minimum of -march=armv8-a+crypto for armclang <= 6.9

Warning

MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY cannot be defined at the same time as MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT.

MBEDTLS_SHA512_SMALLER

Enable an implementation of SHA-512 that has lower ROM footprint but also lower performance.

Uncomment to enable the smaller implementation of SHA512.

MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT

Enable acceleration of the SHA-512 and SHA-384 cryptographic hash algorithms with the ARMv8 cryptographic extensions if they are available at runtime. If not, the library will fall back to the C implementation.

Requires: The SHA-512 built-in implementation

Module: drivers/builtin/src/sha512.c

Uncomment to have the library check for the A64 SHA-512 crypto extensions and use them if available.

Note

MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT requires the built-in SHA-512 implementation to be present in the build. This implementation is included only if PSA_WANT_ALG_SHA_512 is enabled and this results in MBEDTLS_PSA_BUILTIN_ALG_SHA_512 being defined internally (i.e., no fully-featured, fallback-free accelerator driver is present).

Note

If MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT is defined when building for a non-Aarch64 build it will be silently ignored.

Note

Minimum compiler versions for this feature are Clang 7.0, armclang 6.9 or GCC 8.0.

Note

CFLAGS must be set to a minimum of -march=armv8.2-a+sha3 for armclang 6.9

Warning

MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT cannot be defined at the same time as MBEDTLS_SHA512_USE_A64_CRYPTO_ONLY.

MBEDTLS_SHA512_USE_A64_CRYPTO_ONLY

Enable acceleration of the SHA-512 and SHA-384 cryptographic hash algorithms with the ARMv8 cryptographic extensions, which must be available at runtime or else an illegal instruction fault will occur.

Requires: The SHA-512 built-in implementation

Module: drivers/builtin/src/sha512.c

Uncomment to have the library use the A64 SHA-512 crypto extensions unconditionally.

Note

MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT requires the built-in SHA-512 implementation to be present in the build. This implementation is included only if PSA_WANT_ALG_SHA_512 is enabled and this results in MBEDTLS_PSA_BUILTIN_ALG_SHA_512 being defined internally (i.e., no fully-featured, fallback-free accelerator driver is present).

Note

This allows builds with a smaller code size than with MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT

Note

Minimum compiler versions for this feature are Clang 7.0, armclang 6.9 or GCC 8.0.

Note

CFLAGS must be set to a minimum of -march=armv8.2-a+sha3 for armclang 6.9

Warning

MBEDTLS_SHA512_USE_A64_CRYPTO_ONLY cannot be defined at the same time as MBEDTLS_SHA512_USE_A64_CRYPTO_IF_PRESENT.

MBEDTLS_ECP_FIXED_POINT_OPTIM: Enable fixed-point speed-up

MBEDTLS_ECP_WINDOW_SIZE: Maximum window size used

MBEDTLS_MPI_MAX_SIZE: Maximum number of bytes for usable MPIs.

MBEDTLS_MPI_WINDOW_SIZE: Maximum window size used.

MBEDTLS_RSA_GEN_KEY_MIN_BITS: Minimum RSA key size that can be generated in bits (Minimum possible value is 128 bits)

TF_PSA_CRYPTO_PQCP_MLDSA_ENABLED

Enable mldsa-native from the PQCP (post-quantum code package) driver. This is an integration of https://github.com/pq-code-package/mldsa-native in TF-PSA-Crypto.

Module: drivers/pqcp/src/wrap_mldsa_native.c

Uncomment to include mldsa-native in libtfpsacrypto.

Warning

This option is experimental. It may change or be removed without notice.

TF_PSA_CRYPTO_PQCP_MLDSA_87_ENABLED

Enable mldsa-native from the PQCP (post-quantum code package) driver for the security level 87. This is an integration of https://github.com/pq-code-package/mldsa-native in TF-PSA-Crypto.

Requires: TF_PSA_CRYPTO_PQCP_MLDSA_ENABLED

Module: drivers/pqcp/src/wrap_mldsa_native.c

Uncomment to include MLDSA-87 from mldsa-native in libtfpsacrypto.

Warning

This option is experimental. It may change or be removed without notice.

TF_PSA_CRYPTO_PQCP_OWN_SHAKE

If this option is enabled, the MLDSA implementation from mldsa-native (TF_PSA_CRYPTO_PQCP_MLDSA_ENABLED) will use the SHAKE implementation that’s bundled with mldsa-native. Otherwise mldsa-native will use the TF-PSA-Crypto SHAKE builtin that powers the PSA SHA3 and SHAKE APIs.

The mldsa-native SHAKE implementation is significantly faster on processors that have vector instructions. On other architectures, your mileage may vary.

Module: drivers/pqcp/src/wrap_mldsa_native.c

Uncomment to have mldsa-native use its own SHAKE.

Warning

This option is experimental. It may change or be removed without notice.

Defines

TF_PSA_CRYPTO_CONFIG_VERSION

This file determines which cryptographic mechanisms are enabled through the PSA Cryptography API (psa_xxx() functions).

To enable a cryptographic mechanism, uncomment the definition of the corresponding PSA_WANT_xxx preprocessor symbol. To disable a cryptographic mechanism, comment out the definition of the corresponding PSA_WANT_xxx preprocessor symbol. The names of cryptographic mechanisms correspond to values defined in psa/crypto_values.h, with the prefix PSA_WANT_ instead of PSA_.

Note that many cryptographic mechanisms involve two symbols: one for the key type (PSA_WANT_KEY_TYPE_xxx) and one for the algorithm (PSA_WANT_ALG_xxx). Mechanisms with additional parameters may involve additional symbols. This is an optional version symbol that enables compatibility handling of config files.

It is equal to the TF_PSA_CRYPTO_VERSION_NUMBER of the TF-PSA-Crypto version introduced the config format we want to be compatible with.

TF_PSA_CRYPTO_ALLOW_REMOVED_MECHANISMS