Abstract. We present a general method, based on the usage of typical DBMS primitives, for maintaining authenticated relational tables. The authentication process is managed by an application external to the DBMS, that stores just one hash information of the authentication structure. The method exploits techniques to represent hierarchical data structures into relational tables and queries that allow an efficient selection of the elements needed for authentication.

Outsourced storage has become more and more practical in recent years. Users can now store large amounts of data in multiple servers at a relatively low price. An important issue for outsourced storage systems is to design an efficient scheme to assure users that their data stored at remote servers has not been tampered with. This paper presents a general method and a practical prototype application for verifying the integrity of files in an untrusted network storage service. The verification process is managed by an application running in a trusted environment (typically on the client) that stores just one cryptographic hash value of constant size, corresponding to the "digest" of an authenticated data structure. The proposed integrity verification service can work with any storage service since it is transparent to the storage technology used. Experimental results show that our integrity verification method is efficient and practical for network storage systems.