Bitcoin developers are divided over how to address potential quantum computing threats. Adam Back, CEO of Blockstream, advised at Paris Blockchain Week that optional quantum-resistant upgrades should be developed immediately, despite current quantum computers being largely experimental and having shown only gradual progress over the past quarter-century.
“Proactive changes in a controlled manner are significantly safer than crisis reactions,” stated Back. He highlighted Blockstream’s testing of quantum-resistant transaction signatures on Liquid, Bitcoin’s sister network, noting that the 2021 Taproot upgrade was designed to accommodate new signature methods without disrupting current users.
Echoing his previous comments to CoinDesk, Back suggested a decade-long period for key migration to quantum-safe formats. This stance contrasts with BIP-361, proposed by Jameson Lopp and five others, which calls for phasing out vulnerable addresses on a fixed five-year schedule, freezing coins that don’t migrate. This includes about 1 million bitcoins from Satoshi Nakamoto’s pseudonymous holdings and approximately 5.6 million inactive coins.
Back did not directly address BIP-361 but emphasized the potential for Bitcoin developers to swiftly respond to quantum advancements, citing historical instances of rapid bug fixes. He argued that Bitcoin’s governance model could manage emergencies without predetermined freezes.
The debate centers on whether developers can coordinate rapidly in case of an accelerated threat (as Back suggests) or if a structured freeze is necessary to prevent chaotic migrations (Lopp’s view). Recent insights from Google and Caltech researchers indicate functional quantum computers capable of breaking Bitcoin cryptography might emerge sooner than expected, intensifying the urgency of this discussion.