One strategy to backup encrypted ecryptfs data as suggested by the author of ecryptfs. Useful and simple. Backup the metadata and the raw files with rsync.
A critical utility for ecryptfs called ecryptfs-recover-private which automates and simplifies the process of recovering encrypted home directory data from Ubuntu.
A different strategy to find an encrypted filename from an unencrypted filename under ecryptfs (Ubunut's encrypted home directory system).
Interesting article including a script that figures out a mapping from unencrypted filenames into ecryptfs encrypted filenames. Potentially useful.