schema:             KEY-CERT-SCHEMA
ref:                nx3.key-cert
dir-name:           key-cert
key:                key-cert     required  single    primary schema
key:                method       required  single    > {PGP|X509|MTN}
key:                owner        required  multiple
key:                fingerpr     required  single
key:                certif       required  multiple
key:                org          optional  multiple  lookup=nx3.organisation
key:                remarks      optional  multiple
key:                admin-c      optional  multiple  lookup=nx3.person,nx3.role
key:                tech-c       optional  multiple  lookup=nx3.person,nx3.role
key:                mnt-by       required  multiple  lookup=nx3.mntner
key:                source       required  single    lookup=nx3.registry
mnt-by:             NX3-MNT
source:             NX3