Most of docs for external software describe installing algos for Debian/Ubuntu distro’s only (unfortunately). And sometimes it takes a lot of time to convert dpkg/apt commands to zypper’s analogs in mind, when you read the docs.
zypper ar -f ftp://packman.inode.at/suse/openSUSE_Leap_42.1/ packman
zypper imports packman’s digital key from ftp://packman.inode.at/suse/openSUSE_Leap_42.1/repodata/repomd.xml.key
you only need to use rpm --import if a software vendor has not configured a proper repository, like adobe or google do, while google does provide it’s sign key adobe does not
Don’t overlook the case that zypper also uniquely(compared to other package management systems AFAIK) supports automatically accepting keys, so you can skip importing keys in preparation for adding the repo
I wrote the following wiki page which provides examples for a few of my most useful zypper options