tree 3f6a5aae50ed4d348ce51fe03ccff3b79bd8884e
parent b4a87b07f8e2791eb368bb79fb9ae8c32c7cb82e
author Gilles Peskine <Gilles.Peskine@arm.com> 1664917166 +0200
committer Valerio Setti <valerio.setti@nordicsemi.no> 1675859950 +0100

Don't use pk_write in ecdsa_sign_wrap with USE_PSA_CRYPTO

Under MBEDTLS_USE_PSA_CRYPTO, ecdsa_sign_wrap() was calling
mbedtls_pk_write_key_der() to write a private key in SEC1 format, only to
then extract the part that represents the private value which is what
psa_import_key() actually wants. Instead, call an mpi function to directly
get the private key in the desired format.

This slightly reduces the code size and stack usage, and removes a
dependency on pk_write.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>