The present invention relates to file system authentication and, in particular, authentication of users for accessing files stored on a serverless distributed or peer-to-peer file system. Its objective is to preserve the anonymity of the users and to provide secure and private storage of data for users on a serverless distributed file system. It provides a method of authenticating access to a distributed file system comprising the steps of; receiving a user identifier; retrieving an encrypted validation record identified by the user identifier; decrypting the encrypted validation record so as to provide decrypted information; and authenticating access to data in the distributed file system using the decrypted information.