Core Concepts
A single quantum miner can execute a 51% attack by manipulating block timestamps and difficulty adjustments.
Abstract
The content discusses how a quantum miner with low hashing power can execute a 51% attack on proof-of-work cryptocurrencies like Bitcoin. By using Grover's algorithm, the miner can manipulate block timestamps to increase difficulty, creating a competing chain with more cumulative proof-of-work. The attack exploits the chain work consensus mechanism in Bitcoin, allowing the miner to double-spend transactions and censor others. Variants of the attack are presented to address issues such as lagging timestamps and revenue generation. However, current quantum technology limitations make executing this attack impractical.
Stats
Bitcoin hash-rate: around 500 exa-hashes per second (EH/S)
Probability to win a block per hash: 1/(600 * 5 * 10^20)
Depth of quantum computation for mining: approximately 1600 * sqrt(3 * 10^23)
Time for a single quantum computer to mine a block: roughly once a day
Quotes
"The main advantage quantum miners have over classical miners is that they can use Grover’s algorithm."
"Our work has demonstrated a variety of attacks on Nakamoto consensus using difficulty adjustment."
"Future work could explore whether there are stumbling blocks that prevent the difficulty increase attack for other consensus mechanisms."