Batching Techniques for Accumulators with Applications to IOPs and Stateless Blockchains

Boneh, Dan; Bünz, Benedikt; Fisch, Ben

doi:10.1007/978-3-030-26948-7_20

Cited by 165 publications

(118 citation statements)

References 30 publications

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“…Similar to the multivariate polynomial-based VC from [80], this scheme would also support efficiently updating proofs and updating VC digests after vector updates. Thus, our VC could also be used for building stateless cryptocurrencies [80], [81]. Our VC can be extended with zero-knowledge-like properties using the information-theoretic variant of AMTs (see §V-4).…”

Section: Discussion and Future Workmentioning

confidence: 99%

Towards Scalable Threshold Cryptosystems

Tomescu¹,

Chen²,

Zheng³

et al. 2020

2020 IEEE Symposium on Security and Privacy (SP)

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The resurging interest in Byzantine fault tolerant systems will demand more scalable threshold cryptosystems. Unfortunately, current systems scale poorly, requiring time quadratic in the number of participants. In this paper, we present techniques that help scale threshold signature schemes (TSS), verifiable secret sharing (VSS) and distributed key generation (DKG) protocols to hundreds of thousands of participants and beyond. First, we use efficient algorithms for evaluating polynomials at multiple points to speed up computing Lagrange coefficients when aggregating threshold signatures. As a result, we can aggregate a 130,000 out of 260,000 BLS threshold signature in just 6 seconds (down from 30 minutes). Second, we show how "authenticating" such multipoint evaluations can speed up proving polynomial evaluations, a key step in communicationefficient VSS and DKG protocols. As a result, we reduce the asymptotic (and concrete) computational complexity of VSS and DKG protocols from quadratic time to quasilinear time, at a small increase in communication complexity. For example, using our DKG protocol, we can securely generate a key for the BLS scheme above in 2.3 hours (down from 8 days). Our techniques improve performance for thresholds as small as 255 and generalize to any Lagrange-based threshold scheme, not just threshold signatures. Our work has certain limitations: we require a trusted setup, we focus on synchronous VSS and DKG protocols and we do not address the worst-case complaint overhead in DKGs. Nonetheless, we hope it will spark new interest in designing large-scale distributed systems.

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Section: Discussion and Future Workmentioning

confidence: 99%

Towards Scalable Threshold Cryptosystems

Tomescu¹,

Chen²,

Zheng³

et al. 2020

2020 IEEE Symposium on Security and Privacy (SP)

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“…Data privacy Hyperledger Fabric [62], FairAccess [92], [93] Accumulator Provides Membership Proofs, Anonymity Batching Techniques for Accumulators in Blockchain [94] Aggregate Signature Fast Signature Verification Tested in Bitcoin [95] Commitment Scheme Non-Repudiation Used in Bullteproof [96] and in Monero [58,65] Decentralised White-Box Cryptography Data Privacy Runtime Self-Protection in Blockchain Ledger [123] Zero-Knowledge Proof User and Data privacy Zerocoin [124], Zerocash [57]…”

Section: Access Controlmentioning

confidence: 99%

“…Accumulator A in Zerocoin is defined as: Accumulators can also be employed for range proofs in blockchain. Accumulators are used in [94] to design a stateless blockchain where in order to participate in consensus, the node only needs a constant amount of storage.…”

Section: Accumulatormentioning

confidence: 99%

SoK of Used Cryptography in Blockchain

2019

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The underlying fundaments of blockchain are cryptography and cryptographic concepts that provide reliable and secure decentralized solutions. Although many recent papers study the use-cases of blockchain in different industrial areas, such as finance, health care, legal relations, IoT, information security, and consensus building systems, only few studies scrutinize the cryptographic concepts used in blockchain. To the best of our knowledge, there is no Systematization of Knowledge (SoK) that gives a complete picture of the existing cryptographic concepts which have been deployed or have the potential to be deployed in blockchain. In this paper, we thoroughly review and systematize all cryptographic concepts which are already used in blockchain. Additionally, we give a list of cryptographic concepts which have not yet been applied but have big potentials to improve the current blockchain solutions. We also include possible instantiations of these cryptographic concepts in the blockchain domain. Last but not least, we explicitly postulate 21 challenging problems that cryptographers interested in blockchain can work on.

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“…However, storage cost would improve because the public parameter size of some VC schemes grows linearly with the vector length. We note that [22,6] propose SVC with short parameters based on hidden order groups, but those constructions are better suited for bit vectors.…”

Section: Related Workmentioning

confidence: 99%

Unlinkable Updatable Databases and Oblivious Transfer with Access Control

Damodaran

Rial

2020

Information Security and Privacy

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An oblivious transfer with access control protocol (OTAC) allows us to protect privacy of accesses to a database while enforcing access control policies. Existing OTAC have several shortcomings. First, their design is not modular. Typically, to create an OTAC, an adaptive oblivious transfer protocol (OT) is extended ad-hoc. Consequently, the security of the OT is reanalyzed when proving security of the OTAC, and it is not possible to instantiate the OTAC with any secure OT. Second, existing OTAC do not allow for policy updates. Finally, in practical applications, many messages share the same policy. However, existing OTAC cannot take advantage of that to improve storage efficiency. We propose an UC-secure OTAC that addresses the aforementioned shortcomings. Our OTAC uses as building blocks the ideal functionalities for OT, for zero-knowledge (ZK) and for an unlinkable updatable database (UUD), which we define and construct. UUD is a protocol between an updater U and multiple readers R k . U sets up a database and updates it. R k can read the database by computing UC ZK proofs of an entry in the database, without disclosing what entry is read. In our OTAC, UUD is used to store and read the policies. We construct an UUD based on subvector commitments (SVC). We extend the definition of SVC with update algorithms for commitments and openings, and we provide an UC ZK proof of a subvector. Our efficiency analysis shows that our UUD is practical.

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Batching Techniques for Accumulators with Applications to IOPs and Stateless Blockchains

Cited by 165 publications

References 30 publications

Towards Scalable Threshold Cryptosystems

Towards Scalable Threshold Cryptosystems

SoK of Used Cryptography in Blockchain

Unlinkable Updatable Databases and Oblivious Transfer with Access Control

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