‘Existential Threat’: Bitcoin Proposal Would Freeze Satoshi’s Quantum-Vulnerable Coins

Jameson Lopp, CTO and co-founder of self-custody service Casa, proposed a change to Bitcoin’s software on Tuesday to address quantum computers’ catastrophic potential.

The proposal, which was co-authored by five other developers, would create incentives pushing Bitcoin owners toward cryptographically-sound ways of storing the asset that can’t be compromised by complex computers, and introduce other safeguards.

“It turns quantum security into a private incentive,” the proposal’s abstract states. “Fail to upgrade [to a new address type] and you will certainly lose access to your funds.”

Experts are becoming increasingly concerned that quantum computers, once viewed as a far-off threat, could be used within the next decade to reverse engineer wallets’ private keys. That could potentially flood the market with ancient Bitcoin during a so-called liquidation event. 

That’s if, as Lopp told Decrypt in May, Bitcoin’s community can’t “come together and find consensus.”

Under the proposal, sending funds to quantum-vulnerable addresses would eventually be disallowed, encouraging people to adopt “post-quantum” Bitcoin address types. A subsequent phase would prevent quantum-vulnerable Bitcoin from being spent on a five-year timeline.

A third, optional phase would involve establishing a separate Bitcoin Improvement Proposal, or BIP, to tackle the issue of recovering frozen Bitcoin in a quantum-safe way.

Lopp’s initiative was unveiled alongside the Quantum Bitcoin Summit in San Francisco, an invitation-only event where attendees are gathering to mitigate quantum threats.

Although the proposal would affect only 25% of all Bitcoin, considered vulnerable by a recent Deloitte study, its authors argue that an unprecedented threat requires unprecedented action. Those coins notably include 1 million Bitcoin that’s believed to be owned by Satoshi Nakamoto, Bitcoin’s pseudonymous creator.

“Never before has Bitcoin faced an existential threat to its cryptographic primitives,” it states. “A successful quantum attack on Bitcoin would result in significant economic disruption and damage across the entire ecosystem.”

The proposal introduced on Tuesday makes reference to BIP 360, an upgrade designed by Anduro Senior Protocol Engineer Hunter Beast that introduces certain address types that leverage post-quantum cryptography, with varying levels of security.

Lopp noted to Decrypt in May that quantum signature schemes “are massive in terms of data size” and would likely reignite debate over Bitcoin’s transaction throughput.

Proposals are assigned a BIP number as they are published to the Bitcoin Core GitHub repository, where they are debated and tweaked before being implemented. It’s a consensus-dependent process that, in practice, can move slowly.

Developers have introduced other proposals aimed at steeling Bitcoin’s network, including Marathon Director of Engineering Michael B. Casey. His proposal, dubbed “hourglass,” would limit the pace of transactions from ancient wallets that could one day become vulnerable.