Zether: Towards Privacy in a Smart Contract World

Bünz, Benedikt; Agrawal, Shashank; Zamani, Mahdi; Boneh, Dan

doi:10.1007/978-3-030-51280-4_23

Cited by 195 publications

(129 citation statements)

References 18 publications

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“…Another approach is to provide zero-knowledge proof on the blockchain, such as zk-SNARK [20] and BulletProof [21]. Zerocash [22] and Zether [23] are well-known applications of zero-knowledge proof. However, Zerocash [22] and Zether [23], as well as mixing services, are limited to the confidential transfer of cryptocurrency, i.e., ensuring user anonymity when cryptocurrency is transferred.…”

Section: Blockchain and Privacymentioning

confidence: 99%

“…Zerocash [22] and Zether [23] are well-known applications of zero-knowledge proof. However, Zerocash [22] and Zether [23], as well as mixing services, are limited to the confidential transfer of cryptocurrency, i.e., ensuring user anonymity when cryptocurrency is transferred. Although zk-SNARK [20] and BulletProof [21] can have a wider range of applications, they are not designed for directly performing confidential transactions, but for confidentially verifying the validity of a transaction.…”

Section: Blockchain and Privacymentioning

confidence: 99%

See 1 more Smart Citation

Privacy-Preserving Peer-to-Peer Energy Trading in Blockchain-Enabled Smart Grids Using Functional Encryption

Son

Kwon

et al. 2020

Energies

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Advanced smart grid technologies enable energy prosumers to trade surplus energy from their distributed renewable energy sources with other peer prosumers through peer-to-peer (P2P) energy trading. In many previous works, P2P energy trading was facilitated by blockchain technology through blockchain’s distributive nature and capacity to run smart contracts. However, the feature that all the data and transactions on a blockchain are visible to all blockchain nodes may significantly threaten the privacy of the parties participating in P2P energy trading. There are many previous works that have attempted to mitigate this problem. However, all these works focused on the anonymity of participants but did not protect the data and transactions. To address this issue, we propose a P2P energy trading system on a blockchain where all bids are encrypted and peer matching is performed on the encrypted bids by a functional encryption-based smart contract. The system guarantees that the information encoded in the encrypted bids is protected, but the peer matching transactions are performed by the nodes in a publicly verifiable manner through smart contracts. We verify the feasibility of the proposed system by implementing a prototype composed of smart meters, a distribution system operator (DSO) server, and private Ethereum blockchain.

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Section: Blockchain and Privacymentioning

confidence: 99%

Section: Blockchain and Privacymentioning

confidence: 99%

Privacy-Preserving Peer-to-Peer Energy Trading in Blockchain-Enabled Smart Grids Using Functional Encryption

Son

Kwon

et al. 2020

Energies

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“…Beyond papers found via our search method, we have included 2 relevant papers ( [11], [12]) based on presentations at the conference Theory and Practice of Blockchains 2019 at Aarhus University.…”

Section: ) Manual Additionsmentioning

confidence: 99%

“…In this work, the knowledge of the attacker is limited through concealment of the transaction values. Independently from [42], Bünz et al [12], at the same time, proposed Zether, a scheme that allows confidential and anonymous transactions on the Ethereum-network by using ring-signatures [44] on top of the range proofs.…”

Section: B: Zero-knowledge Proofsmentioning

confidence: 99%

Privacy and Cryptocurrencies—A Systematic Literature Review

2020

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Our transaction history in the current centralized banking system has the ability to reveal a lot of private information for each spender, both to the banking system itself, but also to those entities that surround it (e.g., governments, industry etc). Examples of leaking information constitute the amounts spent, the goods on which the amounts were spent, the spending locations and the users we exchange money with. This knowledge is powerful in the hands of those who have it, and can be used in multiple ways, not always to our benefit. Cryptocurrencies, such as the famous Bitcoin, were proposed as a means to address the limitations of centralized banking systems and to offer its users privacy with regards to their transactional data. In this work, we perform a systematic literature review on the realm of privacy for electronic currencies. We present the development of digital money from electronic cash to cryptocurrencies and focus on the techniques that are employed to enhance user-privacy. Furthermore, we present flaws of the current cryptocurrency systems, which reduce the privacy of the cryptocurrency users. Finally, we describe three research directions to enhance privacy for cryptocurrencies: transaction propagation mechanisms, succinct ZK proof systems without a trusted setup, and specialised trustless zero-knowledge proofs. INDEX TERMS Anonymity, bitcoin, confidentiality, cryptocurrencies, electronic cash, privacy, zero-knowledge.

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“…In addition to hiding the transaction amount and participants, Ethereum also needs to hide the account balance and transaction details of the smart contract. In the past two years, Mobius [ 29 ], Zether [ 30 ], AZTEC [ 31 ], PGC [ 32 ] and other privacy protection schemes for Ethereum were proposed. However, because most of their privacy services are provided based on smart contracts, the expensive consumption of GAS prevents it from being put into practical use.…”

Section: Introductionmentioning

confidence: 99%

RZcoin: Ethereum-Based Decentralized Payment with Optional Privacy Service

Zhao

Bai

Zheng

et al. 2020

Entropy

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As the blockchain 2.0 platform, Ethereum’s turing complete programming language and smart contract components make it play an important role in the commercialization of blockchain. With the further development of blockchain applications, the privacy and security issues of Ethereum have gradually emerged. To solve this problem, we proposed a blockchain privacy protection model called RZcash in the previous work. It implements the dynamically updateable and verifiable hiding of the asset information in Ethereum, namely the account balance and transaction amount. However, RZcash does not pay attention to the key redundancy problem that may be caused by the creation of secret accounts. In addition, the large size of proofs gives it high communication costs. In response to these problems, we further improve RZcash. For the key redundancy problem, we construct a new signature scheme based on the ciphertext equivalent test commitment. Moreover, we use the Schnorr signature and bulletproof to improve the corresponding proof scheme in RZcash, thereby reducing the size of proof. Based on these improvements, we propose a decentralized payment system ,called RZcoin, based on Ethereum. Finally, we implement the algorithm model of RZcoin and evaluate its security and performance. The results show that RZcoin has higher security and Lower communication cost than RZcash.

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Zether: Towards Privacy in a Smart Contract World

Cited by 195 publications

References 18 publications

Privacy-Preserving Peer-to-Peer Energy Trading in Blockchain-Enabled Smart Grids Using Functional Encryption

Privacy-Preserving Peer-to-Peer Energy Trading in Blockchain-Enabled Smart Grids Using Functional Encryption

Privacy and Cryptocurrencies—A Systematic Literature Review

RZcoin: Ethereum-Based Decentralized Payment with Optional Privacy Service

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