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Unlike a traditional bank ledger, in a zero-knowledge system each transaction would reveal no information about the sender, recipient, or amount sent, yet proofs would protect the soundness of the currency from theft and counterfeiting. Unlike physical cash or banking, a digital dollar ledger could offer a real time and publicly auditable report of the supply of money in circulation, and by using zero-knowledge proofs this public accountability can be offered without revealing individual transaction details that could jeopardize the privacy of digital dollar users. A major benefit of this approach is that, unlike traditional cryptocurrencies, the total number of transactions allowed by the system can be made to scale to tens or hundreds of thousands per second.

"A zero-knowledge (ZK) proof is a cryptographic protocol that enables one person (the prover) to convince another (the verifier) that a particular claim is true without disclosing any details about the claim itself. "

"Zero-knowledge schemes have recently become a popular attempt to offer users privacy in an attribute-based credential system. In this article, we do not contest the mathematics of these schemes; we assume it is logically sound. Instead, we draw attention to the trade-off that is made when employing cryptography instead of trusted parties to protect user privacy. We assert that, for these approaches to create the trust required by credential verifiers, they must introduce mechanisms that limit their utility and create significant privacy risk to the user that cuts against data minimization goals. Greater trust must be placed in the shelf life of cryptography to prevent the user from being unwantonly correlated than alternative approaches. Just as we would discourage storing encrypted private data on public blockchains, we discourage this approach here. Lastly, this article introduces the concept of a trusted witness which provides privacy for honest users and solves the privacy-trust problem without the disadvantages of the zero-knowledge approach."

"With a zero-knowledge proof (ZKP), a party can prove that a statement is true without revealing any information except for whether it is indeed true or not. The obvious benefit is privacy since the prover does not need to reveal any additional information, and the second benefit is that it can significantly reduce the cost of verifying the correctness of a statement. ZKPs are increasingly adopted in blockchain applications, where privacy and efficiency still have a lot of room for improvement. While it is expected that ZKP technology will also become ubiquitous in many other areas, the term remains cryptic to many people without a computer science background. In this review article, we shed light on what ZKPs are and how they improve privacy and efficiency and describe applications for blockchains and other use cases."

"What's ultimately so promising about ZKPs is that they have the potential to eliminate a major trade-off inherent in living, working, and transacting online: the convenience, speed, reach, and scale of the internet in exchange for our privacy. They also allow for nuance in a privacy landscape that's often black-and-white. "

"ZKProof promotes best practices for proper development and deployment of zero-knowledge proof (ZKP) systems, aligned with security and interoperability. The ZKProof Community Reference (ZkpComRef) intends to comprehend terminology, examples, explanations and recommendations, driven by research and experience. This serves as a reference from and for the community. The ZkpComRef is a live document. "

"Is it possible to show that something is true without revealing the data that proves it? This is what 'Zero Knowledge Proof' technology proposes, a technique which employs cryptographic algorithms so that various parties can verify the veracity of an item of information without sharing the data that compose it."

ZK-proofs still face challenges. They can't work in isolation. They still need to be attached to a truth source or "oracle." Doubts about computational complexity, usability and scalability remain as well.  But if these hurdles are surmounted, ZK-proofs could offer a 21st-century solution to not only the "fake news" challenge but also the privacy quandary as with CBDCs, providing just enough anonymity for users to comfortably use state-issued digital money but enough accountability so governments can be assured fraudsters or money launderers aren't infiltrating their networks.

"zkp-ID enables companies to guarantee user's privacy while adhering to compliance requirements. In four easy steps a user is authenticated and checked against compliance parameters. After that a zero-knowledge proof (ZKP) - wrapped in a self-sovereign identity (SSI) credential - is decentrally stored in the user wallet."

"I'm going to argue that ZKPs are part of the blockchain shell game. Because blockchains have so many technical faults, ZKPs are touted as a solution - and the two together are so confusing it's easy to pass another complicated concept over our heads. Both are immature technologies where the perfect solution resides at some point in the future, and that's the ideal formula for more influencers to shill their bags. "

"In cryptography, zero knowledge proofs let you convince me that you know something, or have done something, without revealing to me what your secret thing was."

"One of the technologies that will undoubtedly change Web3 is zero-knowledge (ZK) cryptography. ZK has long been considered a potential game-changer for ensuring the privacy, security and integrity of blockchain applications. The rapid investment and development of zero-knowledge proofs is an important signal that the technology is getting ready for prime time."

The BIS Innovation Hub and the Hong Kong Monetary Authority have launched the second phase of Project Aurum. Phase 1.0 tested the feasibility of a technological stack that integrates a wholesale interbank system and a retail e-wallet. Phase 2.0 will now focus on how to enhance privacy for retail central bank digital currencies (CBDC). It will explore several privacy-enhancing technologies, including pseudonymization and zero knowledge proofs, and test how increasing privacy affects the performance and compliance of a system.

This survey starts with a high-level overview of the technical workings of zero-knowledge proofs (ZKPs) with a focus on an increasingly relevant subset of ZKPs called zk-SNARKS. While there have been prior surveys on the algorithmic and theoretical aspects of ZKPs, our work is distinguished by providing a broader view of practical aspects and describing many recently-developed use cases of ZKPs across various domains. These application domains span blockchain privacy, scaling, storage, and interoperability, as well as non-blockchain applications like voting, authentication, timelocks, and machine learning. Aimed at both practitioners and researchers, the survey also covers foundational components and infrastructure such as zero-knowledge virtual machines (zkVM), domain-specific languages (DSLs), supporting libraries, frameworks, and protocols. We conclude with a discussion on future directions, positioning ZKPs as pivotal in the advancement of cryptographic practices and digital privacy across many applications.

"In this 2024 paper we propose, implement, and evaluate two extensions to OpenCBDC, an open-source transaction processor designed for central bank digital currency. First, we enable the central bank to audit the monetary supply. This feature reduces the trust required in sentinels - the most exposed components of this architecture - so that it can in principle be outsourced to intermediaries. Second, we leverage Pedersen commitments and zero-knowledge range proofs to hide transaction amounts while maintaining auditability. This feature improves privacy beyond the level offered by the original OpenCBDC design. Performance measurements show that auditability and privacy reduce the throughput of the shards to 30 % of the original, but the scalability remains close-to-linear in the number of shards. For example, 8 shards can process peak loads of ≈135,000 transactions per second. By adjusting resources, CBDC operators can meet their throughput goals with auditability and privacy."