Compile-time configuration

Configuration file split

All configuration options that are relevant to TF-PSA-Crypto must now be configured in one of its configuration files, namely:

  • TF_PSA_CRYPTO_CONFIG_FILE, if set on the preprocessor command line;
  • otherwise <psa/crypto_config.h>;
  • additionally TF_PSA_CRYPTO_USER_CONFIG_FILE, if set.

Configuration options that are relevant to X.509 or TLS should still be set in the Mbed TLS configuration file (MBEDTLS_CONFIG_FILE or <mbedtls/mbedtls_config.h>, and MBEDTLS_USER_CONFIG_FILE is set). However, you can define all options in the crypto configuration, and Mbed TLS will pick them up.

Generally speaking, the options that must be configured in TF-PSA-Crypto are:

  • options related to platform settings;
  • options related to the choice of cryptographic mechanisms included in the build;
  • options related to the inner workings of cryptographic mechanisms, such as size/memory/performance compromises;
  • options related to crypto-adjacent features, such as ASN.1 and Base64.

See include/psa/crypto_config.h in TF-PSA-Crypto and include/mbedtls/mbedtls_config.h in Mbed TLS for details.

Notably, <psa/crypto_config.h> is no longer limited to PSA_WANT_xxx options.

Note that many options related to cryptography have changed; see the TF-PSA-Crypto migration guide for details.

Split of build_info.h and version.h

TF-PSA-Crypto has a header file <tf-psa-crypto/build_info.h> which includes the configuration file and provides the adjusted configuration macros, similar to <mbedtls/build_info.h> in Mbed TLS. Generally, you should include a feature-specific header file rather than build_info.h.

TF-PSA-Crypto exposes its version through <tf-psa-crypto/version.h>, similar to <mbedtls/version.h> in Mbed TLS.

Removal of check_config.h

The header mbedtls/check_config.h is no longer present. Including it from user configuration files was already obsolete in Mbed TLS 3.x, since it enforces properties the configuration as adjusted by mbedtls/build_info.h, not properties that the user configuration is expected to meet.