Paradigm Launches PACT Proposal for Bitcoin’s Quantum-Ready Future
On May 1, Dan Robinson, a general partner at Paradigm Bitcoin, unveiled a proposal for Provable Address-Control Timestamps (PACTs). This cutting-edge system enables inactive Bitcoin holders to privately timestamp proof of key ownership ahead of the advent of quantum computing, which could help protect Satoshi Nakamoto’s estimated 1.1 million BTC.
Summary
- PACTs function in three phases: employing a secret salt, a BIP-322 ownership proof, and an OpenTimestamps commitment anchored on-chain, all while refraining from any public on-chain transactions.
- If Bitcoin later implements a quantum sunset soft fork, PACT holders can present a STARK zero-knowledge proof to recover their coins while keeping their keys private.
- Robinson remarked that if Satoshi had to disclose keys during any required migration, it would mean “announcing to the world that they are alive and still in possession of their keys.”
Robinson introduced PACTs as a measure against what he identifies as the Satoshi Problem concerning Bitcoin’s quantum vulnerabilities. The official Paradigm post elaborated on this concern: if quantum computers appear before Bitcoin adapts, historic addresses with exposed public keys could be at risk of theft.
If Bitcoin rushes to implement a sunset soft fork to protect those addresses, dormant holders might find themselves forced into a public migration of their coins. PACTs offer a third option, enabling holders to quietly timestamp proof of ownership in 2026, delaying any further actions until a formal rescue mechanism is established.
As reported by crypto.news, approximately 1.7 million BTC remain in address types susceptible to quantum threats, including wallets associated with Satoshi, collectively valued at nearly $75 billion.
The proposal is grounded in BIP-361, authored by Casa CSO Jameson Lopp, which details a gradual transition away from legacy signatures, after which unmigrated coins would be locked.
Bitcoin.com noted that Robinson emphasized the necessity for further standardization in areas such as multisig, complex scripts, and hardware wallet compatibility, indicating that Bitcoin might never fully adopt a quantum sunset.
As reported by crypto.news, discussions regarding Bitcoin’s quantum vulnerabilities intensified in 2026, particularly after Blockstream CEO Adam Back advocated for optional quantum-resistant upgrades at Paris Blockchain Week, opposing the enforced wallet freezes presented in the BIP-361 approach that PACTs aim to support.
Additionally, as highlighted by crypto.news, Naoris Protocol CEO David Carvalho expressed concerns that inactive wallets, including Satoshi’s, could become “easy targets” once quantum computers achieve sufficient capability, warning that a quantum attack on Bitcoin might severely compromise trust in the asset.