Kerberos actually operates on keys. The nfs service key is typically a random one stashed in the keytab. I don't understand the objection to Kerberos tickets

Kerberos actually operates on keys. The nfs service key is typically a random one stashed in the keytab. I don't understand the objection to Kerberos tickets -- it's a single-sign-on system. You can obtain a ticket with a public key if you want, see e.g. http://www.h5l.org/manual/HEAD/info/heimdal/Setting-up-PK_002dINIT.html http://www.h5l.org/manual/HEAD/info/heimdal/Setting-up-PK_00... I don't know how easy it aould be to use SSH keys, but I once designed an authentication system for a scientific facility that was based on PGP keys and a web of trust reflecting administrative/social structures in the days before things like Eduroam and (viable?) NFS4, but not before AFS, which has been successfully used in the same way for a long time. I don't know why anyone would think "Kerberized" wouldn't involve Kerberos, but it's nothing specific to user directories. OrangeFS (nee PVFS) is a userland parallel filesystem (with a kernel driver in Linux) that can use two types of public key security if you want that sort of thing, but I gather that's not widely used.