Implementing oqsprovider

This talk revisits the trials and tribulations of writing an OpenSSL provider for a large family of PQC algorithms. In 2021, initially only PQC KEM algorithms were made available by the author but over time signature, hybrid and composite PQC support got added, too. This work could only succeed with the active support by the core OpenSSL team which this talk will provide examples for. In turn, the author also began to contribute back to OpenSSL core some functions enhancing the OpenSSL provider concept, documenting the benefits of a truly open source cooperation.