Developers behind a new wallet product say they have found a way to address the risks of quantum computing using a smart contract layer that runs alongside Bitcoin without requiring any changes to the network itself.
Postquant Labs unveiled Quip Network’s post-quantum bitcoin wallet on Tuesday, the company told CoinDesk in an email. The product runs on Arch Network, a system that allows developers to create smart contracts anchored directly to Bitcoin rather than on a separate chain or via wrapped tokens.
Quip uses that infrastructure to add a post-quantum signature scheme called WOTS+, short for Winternitz One-Time Signature, on top of Bitcoin’s existing security. WOTS+ is a proven cryptographic technique that does not rely on elliptic curve mathematics that a quantum computer could break.
By using a “Layer 2” (short for a separate network built on top of Bitcoin that processes transactions and back to the main chain), developers can add features without changing Bitcoin’s base layer.
“The Bitcoin community has delayed a solution for years, despite Satoshi himself discussing the quantum problem,” Postquant Labs CEO Colton Dillion said in a statement to CoinDesk. “Developers say any protocol upgrade could take 5-10 years, but with Quip’s approach, we provide similar protection immediately.”
Bitcoin’s quantum readiness
The launch comes amid an active fight over how Bitcoin should respond to quantum risk.
Prominent developer Jameson Lopp and five others proposed BIP-361 two weeks ago, which would phase out vulnerable quantum addresses over a fixed five-year timeframe and freeze coins that don’t migrate, including the roughly 1.1 million bitcoins attributed to pseudonymous creator Satoshi Nakamoto.
Paul Sztorc’s controversial eCash hard fork would copy the Bitcoin chain and send seven sidechains, including a quantum-resistant one, funded in part by reallocating Satoshi pattern coins on the new ledger to investors.
Both proposals have generated rejection from the community.
Quip’s argument is that neither approach is necessary. The setup requires no soft fork, no consensus change, and no community vote. A soft fork is an update to Bitcoin that tightens existing rules so that older software still works, but still needs broad support from miners and nodes to activate. The last major Bitcoin soft fork was Taproot in 2021. The next one, if it happens, could be years away.
Technical trade-offs
In reality, the three approaches do not agree on anything specific. Lopp’s argument is that Layer 2 protection like Quip’s is insufficient because Bitcoin mainnet public keys are still leaked at the time a user transmits a transaction, giving a future quantum attacker a target.
However, there are some caveats. The wallet app will be launched next week instead of today. A third-party audit is underway, but is not complete. Quip’s quantum-resistant accounts already exist on Ethereum and Solana, but the Bitcoin implementation is new and the Arch Network is still relatively early infrastructure.
Dr. Richard Carback, CTO of Postquant Labs, a long-time collaborator of eCash inventor Dr. David Chaum, who is now advising the project, said the approach reduces the window for a quantum attack to just two blocks, about 20 minutes.
(David Chaum’s eCash is the original digital cash protocol from 1983, the academic basis for “blind” signatures and privacy-preserving electronic money. It predates Bitcoin by 25 years and has nothing to do with Bitcoin or Sztorc’s eCash proposal.)
Sztorc’s argument is that incremental patches are exactly why Bitcoin needs a clean fork with quantum resistance built in from the beginning. The Layer 2 approach, which now includes Quip and Blockstream’s hash-based signing work on the Liquid Network, argues that both other positions are overreacting to a threat that better infrastructure can handle without changing Bitcoin itself.
Which approach wins depends in part on how fast quantum computers actually arrive. Bitcoin holders most concerned about quantum risk have historically been the same group most resistant to products wrapped in or anchored in smart contracts.
