tree fa9c65116a0f99e8882f0bfe3a1398ef598a71ed
parent 26b807dae8512ecbca9718e2d237ea14cd8f538a
author Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> 1568882714 +0200
committer Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> 1568882714 +0200

Add config.h option MBEDTLS_PK_SINGLE_HASH

No effect for now, just declaring it here, implemented in subsequent commits.

The option requires MBEDTLS_USE_TINYCRYPT and is incompatible with
MBEDTLS_PK_RSA_ALT_SUPPORT and MBEDTLS_RSA_C.

Currently users (including the X.509 and SSL libraries) assume that if both PK
and RSA are enabled, then RSA is available through PK. If we allowed RSA to be
enabled together with PK_SINGLE_TYPE, we'd break that assumption. Going
through the code to find all place that rely on that assumption and fix them
would be cumbersome, and people who want PK_SINGLE_TYPE are unlikely to care
about RSA anyway, so let's just make them incompatible.

This is also consistent with what's done in the MD module: MD_SINGLE_HASH
requires that exactly one hash be enabled.