Hello,

This is a request for feedback about the next major release of Mbed TLS (TF-PSA-Crypto 1.0 + Mbed TLS 4.0). (Mbed TLS 3.6 LTS will remain supported with its current feature set until at least Q2 2027.) Please reply to this thread or on the GitHub issue linked below. If you wish to leave feedback privately, you can reply privately and your feedback will be anonymized before sharing outside Arm.

https://github.com/Mbed-TLS/TF-PSA-Crypto/issues/107

Should TF-PSA-Crypto 1.0 (and thus Mbed TLS 4.0) have an interface for pseudo-random generation? It will, of course, still have a pseudorandom generator (= deterministic random bit generator = DRBG) internally, to power psa_generate_random(), psa_generate_key(), etc. The question is whether there will still be a public interface to create other DRBG instances, and if so, with what interface.

If you want to be able to create instances of HMAC_DRBG and CTR_DRBG from application code in TF-PSA-Crypto 1.0, please let us know what your use case is. In particular, what parameters do you need (HMAC_DRBG and CTR_DRBG have many)? Do you need reseeding, and if so under whose control (the DRBG, or the caller)? In the absence of feedback, it is likely that HMAC_DRBG and CTR_DRBG will not be publicly available.

Best regards,

--
Gilles Peskine
Mbed TLS developer