Paper 2019/070

Uncle Traps: Harvesting Rewards in a Queue-based Ethereum Mining Pool

Sam M. Werner, Paul J. Pritz, Alexei Zamyatin, and William J. Knottenbelt


Mining pools in Proof-of-Work cryptocurrencies allow miners to pool their computational resources as a means of reducing payout variance. In Ethereum, uncle blocks are valid Proof-of-Work solutions which do not become the head of the blockchain, yet yield rewards if later referenced by main chain blocks. Mining pool operators are faced with the non-trivial task of fairly distributing rewards for both block types among pool participants. Inspired by empirical observations, we formally reconstruct a Sybil attack exploiting the uncle block distribution policy in a queue-based mining pool. To ensure fairness of the queue-based payout scheme, we propose a mitigation. We examine the effectiveness of the attack strategy under the current and the proposed policy via a discrete-event simulation. Our findings show that the observed attack can indeed be obviated by altering the current reward scheme.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. In Proc. 12th EAI International Conference on Performance Evaluation Methodologies and Tools (VALUETOOLS), 2019
queue-based mining poolsethereumuncle blockssybil attack
Contact author(s)
smw16 @ ic ac uk
2019-01-25: received
Short URL
Creative Commons Attribution


      author = {Sam M.  Werner and Paul J.  Pritz and Alexei Zamyatin and William J.  Knottenbelt},
      title = {Uncle Traps: Harvesting Rewards in a Queue-based Ethereum Mining Pool},
      howpublished = {Cryptology ePrint Archive, Paper 2019/070},
      year = {2019},
      doi = {10.1145/3306309.3306328},
      note = {\url{}},
      url = {}
Note: In order to protect the privacy of readers, does not use cookies or embedded third party content.