Update psa-limitations.md

For recent work and latest plans.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
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Manuel Pégourié-Gonnard 2023-03-22 16:06:47 +01:00
parent 52f7edb6ad
commit 03cb87ea3c

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@ -11,11 +11,15 @@ is, of course, to actually do the migration work.
Limitations relevant for G1 (performing crypto operations)
==========================================================
Restartable ECC operations
--------------------------
Restartable (aka interruptible) ECC operations
----------------------------------------------
There is currently no support for that in PSA at all, but it will be added at
some point, see <https://github.com/orgs/Mbed-TLS/projects/1#column-18816849>.
Support for interruptible ECDSA sign/verify was added to PSA in Mbed TLS 3.4.
However support for interruptible ECDH is not present yet. Also, PK, X.509 and
TLS have not yet been adapted to take advantage of the new PSA APIs. See:
- <https://github.com/Mbed-TLS/mbedtls/issues/7292>;
- <https://github.com/Mbed-TLS/mbedtls/issues/7293>;
- <https://github.com/Mbed-TLS/mbedtls/issues/7294>.
Currently, when `MBEDTLS_USE_PSA_CRYPTO` and `MBEDTLS_ECP_RESTARTABLE` are
both enabled, some operations that should be restartable are not (ECDH in TLS
@ -78,6 +82,10 @@ the one that requires the most work, but it would deliver value beyond PSA
migration by implementing RFC 7919. (Implementing RFC 7919 could be done any
time; making it mandatory can only be done in 4.0 or another major version.)
As of early 2023, the plan is to go with option 2 in Mbed TLS 4.0, which has
been announced on the mailing-list and got no push-back, see
<https://github.com/Mbed-TLS/mbedtls/issues/5278>.
RSA-PSS parameters
------------------
@ -321,6 +329,8 @@ probably not acceptable.
in the meantime. Such an extension seems inconvenient and not motivated by
strong security arguments, so it's unclear whether it would be accepted.
Since Mbed TLS 3.4, option 1 is implemented.
Limitations relevant for G2 (isolation of long-term secrets)
============================================================