Verifying multiple replica possession with public key segment under public cloud storage environment

Replication is widely used in cloud storage systems to provide availability and reliability for outsourced cloud data. However, untrusted providers would like to maintain fewer replicas than promise for economic profits or other benefits. Since providers hardly ever offer remote checking tools, it becomes a challenge to validate from user side whether Providers are faithfully keeping enough replicas or not. Existing solutions have several disadvantages, including low efficiency, high computation overload, and lack of supporting for colluding attack. In this article, a collector‐based multiple replica storage model is introduced. Based on that, a novel multiple replica possession proving scheme public key segment is proposed in detail. Particularly, a public key is divided into several private segments, which will be distributed to corresponding storage servers for evidence generation. Only if every replica node shows its correct possession evidence, can the challenge be concluded as success. Theoretical analysis and prototype experiments show the correctness, security, and efficiency of the scheme.