Paper 2020/865

Agora: A Privacy-Aware Data Marketplace

Vlasis Koutsos, Dimitrios Papadopoulos, Dimitris Chatzopoulos, Sasu Tarkoma, and Pan Hui


We propose Agora, the first blockchain-based data marketplace that enables multiple privacy-concerned parties to get compensated for contributing and exchanging data, without relying on a trusted third party during the exchange. Agora achieves data privacy, output verifiability, and atomicity of payments by leveraging cryptographic techniques, and is designed as a decentralized application via smart contracts. Particularly, data generators provide encrypted data to data brokers who use a functional secret key to learn nothing but the output of a specific, agreed upon, function over the raw data. Data consumers can purchase decrypted outputs from the brokers, accompanied by corresponding proofs of correctness. We implement a working prototype of Agora on Ethereum and experimentally evaluate its performance and deployment costs. As a core building block of Agora, we propose a new functional encryption scheme with additional public parameters that operate as a trust anchor for verifying decrypted results.

Available format(s)
Publication info
Preprint. MINOR revision.
Data marketplaceFunctional EncryptionBlockchain
Contact author(s)
vkoutsos @ cse ust hk
2020-07-12: received
Short URL
Creative Commons Attribution


      author = {Vlasis Koutsos and Dimitrios Papadopoulos and Dimitris Chatzopoulos and Sasu Tarkoma and Pan Hui},
      title = {Agora: A Privacy-Aware Data Marketplace},
      howpublished = {Cryptology ePrint Archive, Paper 2020/865},
      year = {2020},
      note = {\url{}},
      url = {}
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