(Short Paper) PieceWork: Generalized Outsourcing Control for Proofs of Work

  • Philip DaianEmail author
  • Ittay Eyal
  • Ari Juels
  • Emin Gün Sirer
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10323)


Most prominent cryptocurrencies utilize proof of work (PoW) to secure their operation, yet PoW suffers from two key undesirable properties. First, the work done is generally wasted, not useful for anything but the gleaned security of the cryptocurrency. Second, PoW is naturally outsourceable, leading to inegalitarian concentration of power in the hands of few so-called pools that command large portions of the system’s computation power.

We introduce a general approach to constructing PoW called PieceWork that tackles both issues. In essence, PieceWork allows for a configurable fraction of PoW computation to be outsourced to workers. Its controlled outsourcing allows for reusing the work towards additional goals such as spam prevention and DoS mitigation, thereby reducing PoW waste. Meanwhile, PieceWork can be tuned to prevent excessive outsourcing. Doing so causes pool operation to be significantly more costly than today. This disincentivizes aggregation of work in mining pools.



This work is funded in part by NSF grants CNS-1330599, CNS-1514163, CNS-1564102, CNS-1561209, and CNS-1518779, ARO grant W911NF-16-1-0145, and IC3 sponsorship from Chain, IBM, and Intel.


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Copyright information

© International Financial Cryptography Association 2017

Authors and Affiliations

  • Philip Daian
    • 1
    Email author
  • Ittay Eyal
    • 1
  • Ari Juels
    • 2
  • Emin Gün Sirer
    • 1
  1. 1.Department of Computer ScienceCornell UniversityIthacaUSA
  2. 2.Jacobs Technion-Cornell InstituteCornell TechNew YorkUSA

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