Summary
- AmericanFortress has introduced ZKPoSP, a post-quantum signature method for hierarchical deterministic wallets.
- This technique substitutes elliptic curve signatures with zero-knowledge proofs, ensuring existing wallet addresses remain unchanged.
- The method builds on previous research into post-quantum ownership without necessitating fund migration.
AmericanFortress, a blockchain security and cryptography firm based in Wyoming, has unveiled a cryptographic framework that may enable Bitcoin and other blockchain wallets to resist future quantum threats without altering current wallet addresses.
In their paper, titled “ZKPoSP: Post-Quantum Zero-Knowledge Proofs for Hierarchical Deterministic Wallets,” the team at AmericanFortress outlines a plan to replace conventional elliptic curve signatures with zero-knowledge proofs while maintaining compatibility with hierarchical deterministic wallets.
They asserted, “Recent advances in quantum hardware, including Google's Willow processor, have significantly shortened the timeline for cryptographically relevant quantum computers.” They highlighted that in the blockchain environment, where standards like BIP32, BIP44, and SLIP-10 govern wallet management, a quantum computer utilizing Shor's algorithm could recover any elliptic-curve private key from its public counterpart, endangering all currently operational wallets.
The study zeroes in on "Q-Day," the stage at which a fault-tolerant quantum computer could leverage Shor's algorithm to derive private keys from public keys, thereby compromising the elliptic curve cryptography employed by Bitcoin and various other blockchains.
Instead of requiring users to shift their funds to new quantum-resistant addresses, the proposed framework substitutes digital signatures with zero-knowledge proofs to validate ownership of a wallet's seed phrase. The authors contend that since the seed remains confidential, legitimate owners could still demonstrate control over their wallets, even if their individual private keys were compromised.
The paper introduces ZKPoSP (Zero-Knowledge Proof of Seed Provenance) and QBIP32, a key derivation approach designed to accommodate multiple elliptic curves while remaining compatible with current hierarchical deterministic wallets.
According to their findings, the AmericanFortress team developed the system using Rust on the RISC Zero zero-knowledge virtual machine. Initial benchmarks indicated proof generation times of approximately 12 to 13 seconds and verification times of about 9 to 10 milliseconds. The paper also discusses a post-Q-Day mode that aims to decrease proving time for certain operations.
Currently, this research has yet to be integrated into any blockchain network. Implementing it would require buy-in from developers, wallet providers, exchanges, miners, and users alike.
Interest in post-quantum cryptography is on the rise as blockchain developers gear up for Q-Day. Bitcoin poses a unique challenge since spending coins reveals their public keys on the blockchain. A powerful quantum computer could exploit these public keys to derive private keys and falsify valid transaction signatures.
This paper is part of a broader movement within the crypto sector to equip blockchain networks for a post-quantum landscape. Earlier this month, Project Eleven suggested a post-quantum recovery system that would allow users to establish ownership of a Bitcoin wallet through its seed phrase rather than a digital signature after Q-Day. In March, BTQ Technologies introduced the first operational implementation of BIP-360 on a dedicated "Bitcoin Quantum" testnet to assess quantum-resistant transaction formats. Furthermore, in May, blockchain analytics firm Glassnode estimated that around 6.04 million Bitcoin, or roughly 30% of the circulating supply, already have publicly exposed keys, while the U.S. Department of Commerce announced over $2 billion in funding for quantum computing initiatives and companies.
Recently, prominent companies including BlackRock, Coinbase, Strategy, Fidelity Digital Assets, and Galaxy formed the Bitcoin Security Consortium, pledging $15 million over three years to bolster Bitcoin security research and counter quantum threats.