New Proposal Offers Bitcoin Holders a Way to Prove Control Without Exposing Themselves to Quantum Computing Risks

Quantum computing has long posed a threat to Bitcoin, particularly for holders of large amounts of the cryptocurrency in older wallets with exposed public keys. This includes the estimated 1.1 million bitcoin, valued at around $84 billion, attributed to the cryptocurrency's pseudonymous creator, Satoshi Nakamoto. A proposed soft fork, or upgrade to the existing network rules, could phase out these vulnerable address types over a five-year period, essentially forcing holders to migrate to quantum-safe formats or risk losing access to their assets. However, this solution raises concerns for long-dormant holders like Satoshi, who would need to publicly reveal themselves to avoid losing access to their assets. To address this issue, Dan Robinson of Paradigm has proposed a concept called Provable Address-Control Timestamps, or PACTs. This approach involves generating a proof of ownership without spending any coins, using a random salt and a standard for signing messages from a Bitcoin address. The proof and salt are then bundled into an on-chain commitment and timestamped using OpenTimestamps, a free service that anchors data onto the Bitcoin blockchain. The details of the commitment remain private until the holder needs to spend their coins. If a soft fork is implemented that freezes quantum-vulnerable coins, the protocol could include a rescue path that accepts a zero-knowledge proof, showing that the holder created their commitment before the advent of quantum hardware. This approach would allow holders like Satoshi to prove control over their assets without exposing themselves to the risks associated with quantum computing, while also respecting dormant property rights. However, the implementation of PACTs would require substantial new infrastructure, including multisig wallets, complex scripts, and hardware wallet support, as well as the adoption of a STARK verification protocol. Ultimately, the success of PACTs relies on the willingness of holders like Satoshi to create a commitment, and the ability of the Bitcoin community to come to a consensus on the necessary upgrades and standards.