TL;DR:
- Carter warns that quantum computing could break Bitcoin’s current signature system and compromise exposed funds.
- It is recommended not to reuse addresses, hide public keys, and prepare for a post-quantum transition.
- Although the attack is not yet feasible, postponing a solution would jeopardize the future security of the network.
Bitcoin‘s security could face the greatest challenge in its history, and it does not come from malicious human actors, but from an inevitable technological advance: quantum computing. Nic Carter, co-founder of Coin Metrics, argues that this development represents the most significant long-term risk to the network.
In a recent essay, he warned that exposed public keys and address reuse could facilitate future attacks if action is not taken in advance. Although the current system remains robust against conventional technologies, the arrival of functional quantum computers would put the protocol’s underlying cryptography in check.
The urgency of post-quantum defense
Bitcoin relies on an asymmetric cryptographic principle that allows public keys to be generated from private keys, without the possibility of doing the reverse. This scheme, based on the secp256k1 elliptic curve, has proven robust for over a decade. However, an advanced quantum machine could solve the mathematical problem that currently protects users, compromising both digital signatures and funds stored in previously used addresses.
Carter does not suggest panic, but he does suggest immediate action. He proposes mitigating the risk by adopting preventive practices, such as not reusing addresses and minimizing the exposure of public keys. In addition, he urges developers, custodians, and users to prepare for a migration to quantum-resistant signature schemes. This transition will require planning, technical coordination, and a roadmap shared by the entire community.
Although there is no evidence that a quantum computer capable of executing these attacks is operational today, waiting passively would be a mistake. The cost of not anticipating this could be irreversible. Preparation is not only possible but essential to safeguard the long-term integrity of Bitcoin. The community has the opportunity to build an effective defense before the threat materializes, thereby strengthening the ecosystem’s resilience in the face of a new technological paradigm.
