CMS and S/MIME
Our fork of OpenSSL as well as oqsprovider together with OpenSSL3 (master) can perform S/MIME and CMS signing operations using post-quantum and hybrid digital signatures.
For instructions on doing post-quantum S/MIME operations, see the OQS-Provider USAGE section “SMIME message signing”.
The easiest way to execute post-quantum S/MIME and CMS signing operations is by using the pre-built openssl 1.1.1 docker image at Docker hub or using the pre-built OpenSSL3 docker image at Docker hub.
Information on post-quantum X.509 certificates can be found here.