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Privacy-Enhancing Cryptography in Distributed Ledgers

Periodic Reporting for period 1 - PRIViLEDGE (Privacy-Enhancing Cryptography in Distributed Ledgers)

Reporting period: 2018-01-01 to 2019-06-30

Blockchain and distributed ledger technologies (DLTs) have emerged as one of the most revolutionary developments in recent years, with the goal of eliminating centralised intermediaries and installing distributed trusted services. Although based on cryptographic techniques at their core, the currently deployed DLTs do not address privacy.
Even the idea of a public ledger that stores a verifiable record of transactions at first appears inherently incompatible with the privacy requirements of many potential applications, which handle sensitive data such as trade secrets and personal information. PRIViLEDGE project targets developing new cryptographic techniques and protocols to protect the data, facilitate these applications and make DLTs deliver on currently unmet promises.
The PRIViLEDGE project produces the following major outcomes: 1) provide efficient privacy-enhancing cryptography (PEC) for enabling the execution of smart contracts on blockchains such that the privacy of users and the privacy of data is respected, 2) develop and demonstrate cryptographic tools that aim at anonymity, transparency, and security and maintain a balance between these goals, for practical deployments of DLT and blockchains, 3) construct efficient cryptographic blockchain consensus protocols that rely on advances in cryptography and satisfy the contradicting demands of verifiability, transparency, and stake-based governance, and 4) provide effective exploitation of the PRIViLEDGE cryptography in real operational environments, for enabling privacy in distributed ledgers.
In the first 18 months, the PRIViLEDGE project has gradually progressed towards all the set objectives. Work started with the state-of-the-art analysis of Privacy-Enhancing Cryptography for Ledgers. Then the requirements for use cases were identified and followed by the research work, which was targeted at the specific use-case related challenges as well as advanced the general project objectives.
In the first 18 months, the project has completed the software architecture development, which has laid a solid groundwork for the successful completion of following use cases. Throughout the reporting period, the PRIViLEDGE results and achievements have been actively disseminated in accordance with the dissemination plan. PRIViLEDGE website, social media accounts, flyer, introductory video, and five blog posts were published on the website on relevant topics. PRIViLEDGE partners have also participated in various events as well as successfully organized the PENCIL workshop.
The aim of PRIViLEDGE is to develop and advance techniques that enhance privacy, anonymity and efficient decentralised consensus for distributed ledgers technologies.
So far, the work in WP1 has focused on defining and refining the requirements to guide the research and implementation tasks in the other WPs.
WP2 has already produced several new notions and definitions, including the concepts of publicly verifiable proofs and timed signatures, as well as additions to the understanding of token management platforms, zero-knowledge proofs, bulletin boards, and ring signatures. Work on new constructions corresponding to these definitions has started and more results are expected in the coming months.
WP3 has delivered new results on verifiable multi-party computation, zero-knowledge proofs, privacy-preserving smart contracts, proof-of-stake protocols, asymmetric trust models, and also two attacks on security of previously proposed protocols. Future work includes refinement of the above material as well as additional work on multi-party computation and server-supported hash signature protocols.
WP4 has developed a unified base architecture of ledgers for all toolkits and use-case prototypes and has started work on defining the specific architectures and implementation of the toolkits and prototypes. Future deliveries include completed toolkits and prototypes which are currently in various development stages from architecture definitions to first proofs of concept.