Proof of Storage-Time: Efficiently Checking Continuous Data Availability

A high-quality outsourced storage service is crucial for many existing applications. For example, hospitals and data centers need to guarantee the availability of their systems to perform routine daily activities. Such a system should protect users against downtime and ensure data availability over time. Continuous data availability is a critical property to measure the quality of an outsourced storage service, which implies that outsourced data is continuously available to the server during the entire storage period. We formally study the Proof of Storage-Time (PoSt), the notion initially proposed in the Filecoin whitepaper, which enables a verifier to audit the continuous data availability of an outsourced storage service. We provide a formal security model of PoSt and generic constructions that are proven secure under our definition. Moreover, our concrete instantiation can yield a PoSt protocol with an extremely efficient verification: a single hash computation to verify a proof of size around 200 bits. This makes our scheme applicable even in the decentralized storage marketplace enabled by blockchain.

[1]  Cong Wang,et al.  Enabling Public Verifiability and Data Dynamics for Storage Security in Cloud Computing , 2009, ESORICS.

[2]  Dan Boneh,et al.  Verifiable Delay Functions , 2018, IACR Cryptol. ePrint Arch..

[3]  Ilan Orlov,et al.  Proofs of Space-Time and Rational Proofs of Storage , 2019, IACR Cryptol. ePrint Arch..

[4]  Dan Boneh,et al.  A Survey of Two Verifiable Delay Functions , 2018, IACR Cryptol. ePrint Arch..

[5]  Shouhuai Xu,et al.  Secure and efficient proof of storage with deduplication , 2012, CODASPY '12.

[6]  Stefan Dziembowski,et al.  Proofs of Space , 2015, CRYPTO.

[7]  Ghassan O. Karame,et al.  Outsourced Proofs of Retrievability , 2014, CCS.

[8]  Eli Ben-Sasson,et al.  Succinct Non-Interactive Zero Knowledge for a von Neumann Architecture , 2014, USENIX Security Symposium.

[9]  Benjamin Wesolowski,et al.  Efficient Verifiable Delay Functions , 2019, Journal of Cryptology.

[10]  Elaine Shi,et al.  Practical dynamic proofs of retrievability , 2013, CCS.

[11]  Krzysztof Pietrzak.  Proofs of Catalytic Space , 2018, IACR Cryptol. ePrint Arch..

[12]  Ghassan O. Karame,et al.  Mirror: Enabling Proofs of Data Replication and Retrievability in the Cloud , 2016, USENIX Security Symposium.

[13]  Ronald L. Rivest,et al.  Time-lock Puzzles and Timed-release Crypto , 1996 .

[14]  Douglas R. Stinson,et al.  Multi-prover proof of retrievability , 2016, IACR Cryptol. ePrint Arch..

[15]  Reza Curtmola,et al.  Provable data possession at untrusted stores , 2007, CCS '07.

[16]  Reza Curtmola,et al.  MR-PDP: Multiple-Replica Provable Data Possession , 2008, 2008 The 28th International Conference on Distributed Computing Systems.

[17]  Giuseppe Ateniese,et al.  Proofs of Space: When Space Is of the Essence , 2014, SCN.

[18]  Yevgeniy Dodis,et al.  Proofs of Retrievability via Hardness Amplification , 2009, IACR Cryptol. ePrint Arch..

[19]  Morris J. Dworkin,et al.  SHA-3 Standard: Permutation-Based Hash and Extendable-Output Functions , 2015 .

[20]  Harriet Morrill,et al.  Achieving continuous availability of IBM systems infrastructures , 2008, IBM Syst. J..

[21]  Ari Juels,et al.  HAIL: a high-availability and integrity layer for cloud storage , 2009, CCS.

[22]  David Cash,et al.  Dynamic Proofs of Retrievability Via Oblivious RAM , 2013, Journal of Cryptology.

[23]  Jeremiah Blocki,et al.  Sustained Space Complexity , 2017, IACR Cryptol. ePrint Arch..

[24]  Hovav Shacham,et al.  Compact Proofs of Retrievability , 2008, Journal of Cryptology.

[25]  Ari Juels,et al.  Proofs of retrievability: theory and implementation , 2009, CCSW '09.

[26]  Nico Döttling,et al.  Tight Verifiable Delay Functions , 2020, IACR Cryptol. ePrint Arch..

[27]  Daniel Davis Wood,et al.  ETHEREUM: A SECURE DECENTRALISED GENERALISED TRANSACTION LEDGER , 2014 .

[28]  Ivan Damgård,et al.  Proofs of Replicated Storage Without Timing Assumptions , 2019, IACR Cryptol. ePrint Arch..

[29]  Ben Fisch,et al.  Tight Proofs of Space and Replication , 2019, IACR Cryptol. ePrint Arch..

[30]  Reza Curtmola,et al.  Remote data checking using provable data possession , 2011, TSEC.

[31]  Krzysztof Pietrzak,et al.  Simple Verifiable Delay Functions , 2018, IACR Cryptol. ePrint Arch..

[32]  Roberto Di Pietro,et al.  Scalable and efficient provable data possession , 2008, IACR Cryptol. ePrint Arch..

[33]  Shouhuai Xu,et al.  Fair and dynamic proofs of retrievability , 2011, CODASPY '11.

[34]  Silvio Micali,et al.  The knowledge complexity of interactive proof-systems , 1985, STOC '85.

[35]  Ari Juels,et al.  Pors: proofs of retrievability for large files , 2007, CCS '07.