EconCS Seminar

 

Lecturer: 

Aviv Yaish (Hebrew University)

Title: 

Uncle Maker: (Time)Stamping Out the Competition in Ethereum

Abstract: 

Cryptocurrencies rely on elaborate incentive mechanisms to encourage entities called "miners" to maintain the system’s integrity in the face of adversaries.

We present and analyze an attack on Ethereum's mechanism, which allows miners to obtain higher mining rewards compared to their honest peers.

This attack is novel in that it relies on manipulating block timestamps and the difficulty-adjustment algorithm to give the miner an advantage whenever block races ensue.

We call our attack Uncle Maker, as it induces a higher rate of uncle blocks.

We describe several variants of the attack, including one that is risk-free for miners.

Our attack differs from past attacks such as Selfish Mining, that have been shown to be profitable but were never observed in practice.
We analyze data from Ethereum's blockchain and show that some miners have been actively running a variant of this attack for several years undetected, making this the first evidence of an attack on a major consensus mechanism.
We present our evidence, as well as estimates of the profits gained by attackers, at the expense of honest miners.

Location: 

Room 130, Feldman Building, Edmond J. Safra Campus.

 

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