For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ohollmann:branches:security:tls:unstable/openSUSE_Tumbleweed/home:ohollmann:branches:security:tls:unstable.repo
zypper refresh
zypper install libressl
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ohollmann:branches:security:tls:unstable/openSUSE_Factory/home:ohollmann:branches:security:tls:unstable.repo
zypper refresh
zypper install libressl