A growing debate has emerged among Bitcoin developers and researchers over how urgently the network should respond to potential quantum computing threats.
The discussion intensified after Coinbase CEO Brian Armstrong said he plans to begin working on the issue personally, adding that it is something the industry needs to solve “sooner rather than later.”
Mow pushes back on urgency
JAN3 CEO Samson Mow pushed back sharply, arguing that acting too quickly could create greater risks than the threat itself.
He stated:
“Solving the QC problem later rather than sooner is the best course of action.”
Mow warned that hastily replacing existing signature schemes like ECDSA or Schnorr could expose Bitcoin to classical computing attacks.
He also flagged that post-quantum (PQ) signatures could be significantly larger, potentially reducing transaction throughput and reigniting debates similar to the Blocksize Wars.
Further, he raised concerns that some proposed PQ approaches could act as a “Trojan horse,” potentially introducing backdoors in random number generation or cryptographic schemes, referencing historical examples tied to Edward Snowden disclosures.
Back and Schnelli echo caution
Blockstream CEO Adam Back argued that insufficiently reviewed PQ implementations could introduce security flaws long before quantum computers pose a credible threat to Bitcoin’s existing encryption.
Back pointed to prior cases of PQ algorithms based on newer mathematical assumptions being broken, and suggested hash-based schemes like SPHINCS+ may offer a more conservative path forward.
Bitcoin developer Jonas Schnelli highlighted that PQ signatures are significantly larger than current Schnorr signatures, and that PQ algorithms have undergone far less real-world testing than the cryptography Bitcoin currently relies on.
Schnelli wrote:
“The cure, rushed, could be worse than the disease.”
Limited exposure today
Some contributors noted that many Bitcoin holdings remain protected because public keys are not exposed until funds are spent, limiting the current attack surface for quantum adversaries.
Proposals like BIP-360 were also referenced, which aim to introduce optional post-quantum protections without requiring immediate network-wide changes.
Across the conversation, a consistent theme emerged:
Changes to Bitcoin’s cryptographic foundations should be approached with extensive review and testing, with most researchers agreeing that practical quantum risks to Bitcoin remain years away.
