Bitcoin exchanges can reduce quantum exposure before a network upgrade

A technical analysis of Bitcoin's quantum computing readiness highlights that major crypto exchanges and custodians can significantly reduce public-key exposure before a full network upgrade is implemented. According to Glassnode data, roughly 1.6 million BTC held across exchange-related outputs currently exhibit visible public keys on-chain, representing about 40% of all operationally exposed Bitcoin supply. While active key visibility does not present an immediate threat today, it defines coins vulnerable to future Shor's algorithm-capable quantum machines. The debate gained traction following a post-quantum workshop hosted by Coinbase, Stanford, and Localhost Research, which concluded without consensus on a single signature scheme due to tradeoffs in key size, device latency, and key management. Unlike dormant or lost coins, active exchange wallets can mitigate at-rest exposure immediately through routine address rotation, enhanced change-output policies, and strict address hygiene. Separately, draft BIP-360 proposes Pay-to-Merkle-Root (P2MR) as a soft fork to remove Taproot's default key-path spend and protect outputs at rest, though short-exposure mempool risks will require separate cryptographic signature schemes.