FM-DPDP: Fine-grained Multicopy Dynamic Provable Data Possession with flexible storage

In recent years, the widespread adoption of cloud storage has surged alongside the rapid and exponential increase in data. However, cloud storage also brings an integrity threat with remote data. Consequently, many schemes have been proposed to safeguard remote data integrity. In these researches, multicopy Provable data possession (PDP) is an effective method for enhancing data security. Unfortunately, most existing schemes only support integer multiples of copies, which may reduce the practicality of these schemes. In this paper, we use the Ternary Copy Hash Tree (TCHT) as a dynamic structure to propose a Fine-grained Multicopy Dynamic Provable Data Possession (FM-DPDP) scheme. Unlike traditional multicopy PDP, which only supports an integer number of copies, FM-DPDP supports fine-grained replication. This means that the number of replicas can be any rational number greater than 1. Furthermore, The FM-DPDP also supports, data restoration, privacy preservation and data dynamics. The security analysis demonstrates that the proposed scheme is correct and unforgeability. Besides, we compare FM-DPDP with other relevant schemes. The evaluation indicates that our scheme offers additional functionalities while maintaining comparable computational cost and communication efficiency to other schemes.