In ownCloud 8, the phpass library was removed.
See relevant OC changes: [[ https://github.com/owncloud/3rdparty/pull/144 | PR144]], [[https://github.com/owncloud/core/commit/c4d7483a0a7d1ea75bf06d0a4e726e2b150be81f|Example]], [[https://mailman.owncloud.org/pipermail/devel/2014-November/000711.html|MailingList]]