For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/openSUSE_Tumbleweed/devel:microos.repo
zypper refresh
zypper install disk-encryption-tool
For openSUSE Factory ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/openSUSE_Factory_ARM/devel:microos.repo
zypper refresh
zypper install disk-encryption-tool
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/16.0/devel:microos.repo
zypper refresh
zypper install disk-encryption-tool