19-01-2013, 10:05 AM
Dynamic Provable Data Possession
ABSTRACT
As storage-outsourcing services and resource-sharing networks have become popular, the problem of efficiently proving the integrity of data stored at trusted servers has received increased attention. In the provable data possession (PDP) model, the client preprocesses the data and then sends it to an entrusted server for storage, while keeping a small amount of meta-data. The client later asks the server to prove that the stored data has not been tampered with or deleted (without downloading the actual data). However, the original PDP scheme applies only to static files. We present a definitional framework and efficient constructions for dynamic provable data possession (DPDP), which extends the PDP model to support provable updates to stored data. We use a new version of authenticated dictionaries based on rank information. The price of dynamic updates is a performance change from (or O(n ǫ log n)), for a file consisting of n blocks, while maintaining the same (or better, respectively) probability of misbehavior detection. Our experiments show that this slowdown is very low in practice .We also show how to apply our DPDP scheme to outsourced file systems and version control systems .