Bitcoin's quantum debate splits as Adam Back pushes optional upgrades over forced freeze
TL;DR
Adam Back, CEO of Blockstream, advocates for optional quantum-resistant upgrades for Bitcoin, emphasizing proactive measures over reactive ones. He believes that current quantum computing threats are still in early stages and that the Taproot upgrade allows for flexible adaptations.
Key points
- Adam Back advocates for optional quantum-resistant upgrades for Bitcoin
- Current quantum computers are still in early experimental stages
- The Taproot upgrade allows for flexible adaptation to new signature methods
Mentioned in this story
The quantum computing threat has some of Bitcoin's most vocal developers landing in wildly different places.
Blockstream's CEO, Adam Back, told Paris Blockchain Week attendees on Wednesday that Bitcoin developers should start building optional quantum-resistant upgrades now, even though current quantum computers remain "essentially lab experiments" with progress that has been "incremental" over the 25 years he has tracked the field.
"Preparation is key. Making changes in a controlled way is far safer than reacting in a crisis," the Blockstream CEO said.
He pointed to his company's work testing quantum-resistant transaction signatures on Liquid, a sister network to Bitcoin. He argued that a 2021 Bitcoin upgrade called Taproot was designed flexibly enough to accept new signature methods without disrupting anyone currently using the network.
The comments echo Back's position from last week, when he told CoinDesk that users should have roughly a decade to migrate their keys to quantum-resistant formats.
What is different now is the context around them. BIP-361, the proposal from Jameson Lopp and five other developers published Tuesday, would phase out quantum-vulnerable addresses on a fixed five-year timeline and freeze any coins that fail to migrate.
That includes roughly 1 million bitcoin attributed to Bitcoin's pseudonymous creator, Satoshi Nakamoto, and an estimated 5.6 million coins, Loppsays, have not moved in over a decade.
Back's framing reads as the implicit alternative to BIP-361's forced migration. He did not mention the Lopp proposal directly, but addressed the underlying question of whether Bitcoin's developer community can respond quickly to a sudden quantum breakthrough.
"Bugs have been identified and fixed within hours. When something becomes urgent, it focuses attention and drives consensus," he said, suggesting Bitcoin's rough-consensus governance could handle an emergency without pre-scheduled freezes years in advance.
The two positions represent the core disagreement shaping Bitcoin's quantum debate.
Back is betting that developers can coordinate quickly if the threat accelerates. Lopp is betting they cannot, and that a scheduled freeze is the only way to avoid a disorderly migration under pressure.
Google and Caltech researchers said last month that functional quantum computers capable of breaking Bitcoin's cryptography could arrive sooner than previously estimated, which is what moved the debate from theoretical to active.
Q&A
What did Adam Back say about quantum-resistant upgrades for Bitcoin?
Adam Back suggested that Bitcoin developers should begin building optional quantum-resistant upgrades now to prepare for future threats from quantum computing.
How does the Taproot upgrade relate to quantum resistance in Bitcoin?
The Taproot upgrade was designed to be flexible enough to incorporate new signature methods, which can include quantum-resistant options without disrupting current users.
What timeline did Adam Back provide for migrating to quantum-resistant formats?
Adam Back indicated that users should have approximately a decade to migrate their keys to quantum-resistant formats in anticipation of future quantum computing threats.
