Paradigm partners release PACTs proposal, allowing holders from the Satoshi era to prove control without moving BTC

Concerns about quantum computing in Bitcoin always revolve around a "Satoshi-related problem." If a sufficiently powerful quantum computer emerges, millions of Bitcoins stored in old wallets with exposed public keys may face the risk of being stolen, including approximately 1.1 million Bitcoins that are allegedly owned by the anonymous creator Satoshi, currently valued at about $84 billion.

Senior developer Jameson Lopp and five other developers formally proposed this plan through BIP-361 in mid-April, which aims to gradually phase out addresses vulnerable to quantum attacks over a five-year timeline and freeze any coins that fail to complete the migration. However, this proposal creates another issue: Satoshi and all other long-dormant holders would have to publicly "reveal themselves," or risk losing access to their assets.

Dan Robinson, a general partner at Paradigm, released a proposal on Friday that suggests a way to circumvent this trade-off, with the core concept being "Provable Address Control Time Stamps" (PACTs). The main idea of PACTs is not to move coins, but to timestamp ownership proofs on specific dates, without disclosing any information externally until the wallet owner truly needs to spend.

If Bitcoin later implements a soft fork to freeze coins vulnerable to quantum attacks, the protocol could include a rescue path that accepts STARK proofs (a type of zero-knowledge proof that remains secure against quantum computers), proving that the holder created their commitment before the existence of quantum hardware. When the holder wishes to spend, they submit this proof, and the network releases the corresponding coins. This redemption process will not reveal any information about the address, amount, or even the original timestamp creation time.