Post-quantum cryptography researcher Joseph Carney published an analysis on March 5th that provides hard numbers on quantum threats to Bitcoin.
According to their research, there are at least 186.7 million unused transaction outputs (UTXOs) in the network that need to be migrated. New signature scheme before computers Quantum technology has successfully broken through the current encryption algorithm ECDSA-256.
Carney’s analysis suggests that in a theoretical scenario where 100% of the Bitcoin block’s capacity is used solely for this transition, and other economic activity is completely shut down. 76 consecutive days are required to complete the process. But Carney warned that this “theoretical lower bound” is unrealistic, as networks must continue to process commerce and everyday payments while protecting themselves.
A more realistic prediction based on IonQ’s roadmap (estimated to reach 1,600 logical qubits by the end of 2028, as reported by CriptoNoticias) is around 1,032 days for Bitcoin to take action.. How to achieve your goals without disrupting network usageat least 7.4% of the space in each block must be reserved starting immediately. Each day of technical agreement delay increases this percentage and reduces the space available for remaining users.
The main contradiction is the physical limitations of the protocols, not just advances in quantum hardware. “Block space” is a limited amount of storage (approximately 4MB for SegWit) that is generated every 10 minutes.
Carney’s research shows that the risk is not just the loss of personal funds; Extreme congestion on the network when trying to migrate at the last minute. If inaction increases the block rate required for security, transaction fees could rise to a level where small savers are trapped in vulnerable addresses and unable to access the “pathways” to secure addresses before the quantum age arrives.
Bitcoin has already been hit by a period of congestion, which has seen a significant increase in the price per transaction. Things that affect normal network usage. The last time there was a significant price increase was in April 2024, at which point the price per trade reached a historical high of over $124.
The important point to emphasize is that the advent of quantum computing does not mean the end of Bitcoin, but it does mean that BTC stored in vulnerable addresses can be attacked. As Carney points out, this situation would require a large movement of funds to protected addresses. According to Project Eleven, 33% of BTC in circulation, approximately 7 million BTC, is vulnerable to quantum.
Consensus and quantum finance challenges
The urgency of Carney’s approach lies in Bitcoin’s historic update times. Previous improvements like SegWit and Taproot required years of technical discussion and social consensus before being enabled.. There are currently no updates planned for quantum threats, but Bitcoin developers are working on post-quantum improvements such as BIP-360, which prevents public keys from being exposed on the network.
Advances in quantum hardware are not a remote possibility. Leading companies in the space, such as IonQ, have strengthened their position as the largest quantum companies after receiving significant capital injections in the US. This capital support will accelerate the arrival of processors capable of running the algorithms. This is from Shor, which is specifically designed to compromise the public key cryptography that currently protects funds on the blockchain.