Bitcoin and Quantum Computing: BIP 360 (P2MR) Enters the Technical Debate

Updated February 15, 2026.

BIP 360 and Pay-to-Merkle-Root: A Step Towards Post-Quantum Defenses

In recent days, the “quantum threat” to Bitcoin has resurfaced, particularly following discussions around BIP 360 (Pay-to-Merkle-Root, P2MR). It’s important to clarify: this is not an emergency patch, but a long-term path to reduce the attack surface related to the exposure of public keys, while maintaining some of the flexibility introduced by Taproot.

What P2MR Proposes, in Simple Terms

P2MR aims to preserve the idea of Taproot’s script trees, but removes the “key path spend” which, in a future with cryptographically relevant quantum computers, would represent a more vulnerable point. In other words, it encourages the use of paths that reduce the exposure of information that could be useful to an attacker in a “harvest now, decrypt later” scenario.

How Real is the Risk Today?

The CoinShares research highlights that, as of today, the quantum risk is not imminent, and that the required computational power is far beyond current capabilities. The point is not to “panic,” but to plan: Bitcoin has an intentionally slow pace of change, and therefore it is rational to begin discussing solutions long before the risk becomes practical.

The Problem with Public Key-Exposed Addresses

Historically, some types of outputs and some spending methods expose the public key more directly. If, in the future, current cryptography becomes vulnerable, those coins would theoretically be more “attackable.” This does not mean that the entire network is in danger tomorrow; it means that there are areas with a different risk profile.

Trade-offs: Costs, Privacy, and Migration

Every post-quantum defense proposal involves trade-offs:

transaction costs and data size
privacy (how much changes in what is revealed on-chain)
slow and voluntary migration: users must update wallets and habits

What to Watch For

evolution of the proposal and technical discussions
attitude of wallet providers (adoption, UX, compatibility)
any post-quantum standards and their impact on design

Sources

bip360.org: text of the BIP 360 / P2MR proposal.
CoinShares (February 2026): “Quantum vulnerability in Bitcoin: a manageable risk.”