Over the recent weeks, concerns have been rising in the Bitcoin community over how the network would withstand future advances in quantum computing, which some experts say could eventually break the Elliptic Curve Digital Signature Algorithm (ECDSA) that currently secures the network.
A recent proposal from Paradigm researcher Dan Robinson focuses on how to protect Bitcoin wallets that have been inactive for years. He introduced a concept called Provable Address-Control Timestamps (PACTs), which is meant to safeguard old wallets, including some early Bitcoin holdings that are believed to be linked to Bitcoin’s creator, Satoshi Nakamoto.
The risk of quantum “sunsetting”
Currently, the most prominent competing solution to the quantum threat is BIP-361, proposed by Casa Chief Security Officer Jameson Lopp. BIP-361 suggests a multi-year migration window allowing users to move funds to quantum-resistant addresses, after which legacy signatures would be “sunset” and permanently frozen.
Robinson says the concern is that future quantum computers could become powerful enough to break Bitcoin’s current security system and potentially access exposed wallets to move funds. He warned that this risk could push the Bitcoin network toward “sunsetting” older address types to stay secure. But such a move could create complications for dormant holders, who may be forced to prove ownership or risk losing access to their coins.
The PACTs concept is designed as an alternative approach. It would allow users to signal control over their funds in a privacy-preserving way, without exposing personal identity or moving their Bitcoin.
Quantum risk and Bitcoin debate
Robinson said Bitcoin was originally designed to let people store value for long periods without needing to move their coins. That design choice, he noted, now raises a concern as quantum computing continues to advance.
He warned that if quantum machines become powerful enough, they could break ECDSA, the cryptographic system that secures Bitcoin wallets today. In that case, even very old and inactive wallets could be exposed, including some tied to Bitcoin’s earliest history. He estimated that at risk holdings could exceed $75 billion.
He also said the risk is not limited to future technology. If quantum attackers reach that capability first, they could potentially drain exposed wallets, which could move large amounts of funds quickly and disrupt markets. That kind of event, he added, could also prompt closer regulatory attention on Bitcoin’s security.
One option being discussed is to phase out older wallet formats that are more vulnerable. But Robinson pointed out a drawback. Users would likely need to move their funds to newer addresses, which could reveal wallet activity and reduce privacy, especially for early or dormant holders.
As an alternative, he suggested a different approach that avoids moving coins altogether. The idea relies on cryptographic timestamps that can prove ownership in a more discreet way, without forcing users to expose their identities or change where their Bitcoin is stored.
PACT proposal and technical approach
Robinson’s proposed PACT system is designed to let Bitcoin holders prove they once controlled a wallet without revealing their private keys. The idea uses Bitcoin itself as a kind of public timestamp service. It also draws on existing tools such as OpenTimestamps and cryptographic proof methods that allow verification without exposing sensitive data.
In practice, users would generate a secret value and sign a standard Bitcoin message. That information is then turned into a cryptographic fingerprint and recorded on the Bitcoin network through timestamping services. Later, users could use that record to show they had control of a wallet at a certain point in time.
But according to Robinson, the system would only work if Bitcoin itself evolves. It would likely require future rules that allow coins from older “sunset” addresses to be moved or validated through cryptographic proofs rather than traditional keys. He also noted that more advanced verification tools, including post-quantum systems, would need to be added over time.
He acknowledged the approach is not complete. It does not yet support more complex setups such as multisignature wallets or custodial accounts. It also depends on agreement from the broader Bitcoin developer community, which makes adoption uncertain.
At the same time, research into quantum computing continues to progress. Some experiments have shown early progress in breaking small elliptic curve keys, although real-world systems remain out of reach for now. Still, the proposal adds to a wider debate in the Bitcoin community over how to prepare for a future where quantum computing could challenge the network’s current security model.
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