Domain: Finance

Problem identification: 

To reduce the energy depletion due to exhaustive hash queries. 

Why Blockchain: 

To avoid the necessity of trusting a centralized banking system.

Functional Description

The miner’s stake is measured as the product between the held tokens and the holding time for them (“coin age”), allowing a miner to consume its “coin ages” to reduce the difficulty of the puzzle to solve.

Consensus mechanism used

  • Proof of Stake (PoS)

Current status

  • Market cap above $5 million.

Focus point commentary indicating the value of the case study in relation with learning modules

Learning Modules Focus Points

Consensus Presents a use case of the PoS consensus mechanism


  • Vulnerability to “nothing-at-stake” attacks.
  • Vulnerability to “grinding” attacks

Alternative Approaches:

  • Ouroboros


  1. S. King and S. Nadal, “Ppcoin: Peer-to-peer crypto-currency with proof-of-stake. Peercoin whitepaper” Aug. 2012.
  2. Larimer, D. (2013). Transactions as proof-of-stake. Nov-2013.
  3. Anderson, L., Holz, R., Ponomarev, A., Rimba, P., & Weber, I. (2016). New kids on the block: an analysis of modern blockchains. arXiv:1606.06530.