Since sensitive file data may be transmitted or received from a server by the NFS protocol, authentication, privacy, and data integrity issues should be addressed by implementations of this protocol.
As with the previous protocol revision (version 2), NFS version 3 defers to the authentication provisions of the supporting RPC protocol [RFC1057], and assumes that data privacy and integrity are provided by underlying transport layers as available in each implementation of the protocol. See section 4.4 for a discussion relating to file access permissions.