# Coinbase Outlines Bitcoin Quantum Plan, Flags 6.9 Million BTC

By Simon Yoon

Canonical URL: https://www.tokenpost.com/news/technology/37567
Published: 2026-10-22T06:28:49.000Z
Updated: 2026-10-22T06:28:49.000Z
Section: Technology

> Options include a new output type and a hybrid spending design. Coinbase has not selected a signature system or set a migration timetable.

Coinbase has outlined ways Bitcoin (BTC) could adopt post-quantum signatures, including flexible designs for changing cryptography during a network transition that could take years to complete.

In an Oct. 13 post, Coinbase discussed P2MR, proposed in draft BIP-360, and P2TRv2 as possible output designs. A staged option would let the same funds have two alternative spending paths: one authorized by a conventional ECDSA or Schnorr key and the other by a post-quantum key. The structure could let Bitcoin introduce, replace or supplement signature systems without a complete redesign. Coinbase has not chosen a signature system or set a migration timetable.

BIP-360 proposes a new P2MR output type without Taproot’s key path. The proposal addresses long-exposure attacks but does not add post-quantum signatures, which may be needed to address short-exposure attacks. The design is one possible part of a wider transition, not a completed quantum-safe upgrade.

Coinbase has framed the designs as options for discussion rather than final instructions for Bitcoin developers. The signature choice and migration timing remain open, as does the treatment of abandoned or inaccessible coins. The hybrid approach would keep conventional and post-quantum authorization available for the same funds during a staged changeover, without requiring a single signature choice now.

An estimated 6.9 million BTC were in the most exposed category because relevant public-key information had appeared on-chain. No quantum computer capable of threatening Bitcoin existed when the estimate was published in April. Expert timelines made at least a decade seem likely, while leaving open the possibility of a shorter timeline.

The exposure concerns wallet signatures, which prove control of funds. A sufficiently capable quantum computer could use exposed public-key information to derive private keys and authorize transactions. Bitcoin’s mining, hash functions and historical ledger faced no comparable quantum threat at the time.

“Bitcoin consensus changes and ecosystem migrations can take years,” Shashank Agrawal, author of Coinbase’s post, wrote. Coinbase has left the technical choices and schedule unsettled.