Transaction Anonymity and Accountability in Cryptocurrencies

Projekter: ProjektForskning

Projektdetaljer

Beskrivelse

Most of current blockchain based cryptocurrencies allow users to transfer coins among themselves using pseudonyms. However, the fund movements among these pseudonyms are openly available in the blockchain and it has been shown that at times pseudonyms can be linked to specific users, breaking anonymity. On the other hand, cryptocurrency protocols such as Zerocash provide a high level of anonymity where it is not possible to obtain any information about the amounts and users involved in transactions written on the blockchain. While such protocols solve the privacy issues in classical cryptocurrencies, they introduce regulatory problems, as they do not allow for lawful tracking of financial transactions. This project aims at answering the following questions:
1.When and how should anonymity be revoked and which private data should be revealed?
2.What should be the fundamental security guarantees of a cryptocurrency protocol that ensures both transaction anonymity and accountability?
3.How can an efficient anonymous transaction protocol with accountability features achieving these guarantees be constructed?

Nøgleresultater

The main results of the project were the following: Encryption to the Future, a paradigm for sending messages towards anonymous committees chosen at random, which is essential for YOSO MPC; YOLO YOSO, a state-of-the-art publicly verifiable secret sharing scheme with an associated re-sharing protocol for keeping secrets alive on blockchains and YOSO MPC; Layered MPC, a crisp model for MPC over blockchains and feasibility results on achieving optimal corruption ratios with perfect security in this model; Musen, an aggregatable and forward secure VRF scheme that can be used for stronger encryption to the future and compact representations of Proof-of-Stake blockchains; Updatable privacy preserving blueprints, a notion that allows for an auditor to learn whether financial transactions on traditional financial systems or blockchain-based cryptocurrencies have exceeded a given risk threshold or a given permitted amount, while learning nothing else.
AkronymTrA^2C
StatusAfsluttet
Effektiv start/slut dato01/07/201930/06/2024

Samarbejdspartnere

Finansiering

  • Danmarks Frie Forskningsfond: 2.879.654,00 kr.

Emneord

  • Multiparty Computation
  • Blockchain
  • Privacy
  • Accountability
  • MPC

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