For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mcaj/openSUSE_Tumbleweed/home:mcaj.repo
zypper refresh
zypper install libgcrypt11
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mcaj/15.5/home:mcaj.repo
zypper refresh
zypper install libgcrypt11
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mcaj/15.4/home:mcaj.repo
zypper refresh
zypper install libgcrypt11