A Major Breakthrough Simplifies Bitcoin's Post-Quantum Transition

Researchers in post-quantum cryptography unveiled on July 29 a zero-knowledge proof system capable of protecting Bitcoin wallets without changing existing addresses. Signed by AmericanFortress, this breakthrough comes as the threat of Q-Day becomes clearer. A viable solution for the ecosystem?

A Shield That Rely on Zero-Knowledge Proof

Since Google’s Willow processor brought the horizon of Q-Day closer, the race to protect blockchains has intensified. The challenge is immense: migrating millions of Bitcoin addresses to post-quantum formats looks like a logistical headache. AmericanFortress, a cybersecurity company based in Wyoming, has precisely designed a different approach to bypass this difficulty.

Presented in a Decrypt article titled “ZKPoSP: Post-Quantum Zero-Knowledge Proofs for Hierarchical Deterministic Wallets“, the researchers’ proposal tackles the heart of the problem.

Rather than requiring massive fund migration, the ZKPoSP system replaces traditional digital signatures with zero-knowledge proofs. These proofs verify that the owner indeed holds the wallet’s seed phrase without ever exposing this sensitive information.

“Recent advances in quantum hardware, notably Google’s Willow processor, have significantly reduced the timeline for relevant cryptographic quantum computers to arrive,” the authors write. 

In the blockchain universe, where BIP32, BIP44, and SLIP-10 standards dominate wallet management, a quantum computer running Shor’s algorithm can retrieve any ECDSA private key from the corresponding public key.

The complementary QBIP32 protocol, also detailed in the study, supports multiple elliptic curves while remaining compatible with existing HD wallets. Implemented in Rust via the zero-knowledge RISC Zero virtual machine, the system produced proofs in 12 to 13 seconds for verification in 9 to 10 milliseconds. A “post-Q-Day” mode further reduces this time for certain operations.

Six Million Bitcoins Already Vulnerable on the Chain

The vulnerability of bitcoin to quantum computing is not a theoretical hypothesis. Last May, the analytics platform Glassnode estimated that about 6.04 million bitcoins, nearly 30% of the circulating supply, already have their public keys exposed on the blockchain. Every transaction spending bitcoins makes the public key visible, offering an attack surface to a future quantum computer.

This realization has pushed industry heavyweights to act. Last week, BlackRock, Coinbase, Strategy, Fidelity Digital Assets, and Galaxy formalized the Bitcoin Security Consortium, endowed with $15 million over three years. Their mission: to fund research on Bitcoin’s security against quantum attacks. The US Department of Commerce also announced more than $2 billion in grants for quantum computing companies.

No blockchain network has yet adopted AmericanFortress’s paper. Any deployment would require agreement from developers, wallet providers, exchanges, and miners.

The Race for Post-Quantum Solutions Accelerates

The race for post-quantum shielding is not limited to AmericanFortress. Earlier this month, Project Eleven proposed a recovery mechanism allowing holders to prove wallet ownership via the seed phrase rather than by a classic digital signature after Q-Day.

In March, BTQ Technologies deployed the first functional implementation of BIP-360 on a testnet named “Bitcoin Quantum”, designed to evaluate transaction formats resistant to quantum attacks. These initiatives, combined with the consortium’s formation, outline an ecosystem that is taking the threat seriously.

In the blockchain universe, a quantum computer running Shor’s algorithm can retrieve any ECDSA private key from the corresponding public key, threatening all wallets in use today.

The researchers emphasize a central point: the seed phrase remains secret, so legitimate owners could continue to prove control of their funds even if individual private keys were compromised.

In short, AmericanFortress’s proposal adds a promising piece to the post-quantum security puzzle. The bitcoin ecosystem now has several paths, from ZKPoSP to BIP-360 and seed recovery mechanisms, converging toward the same goal. The challenge remains to transform these laboratory prototypes into industry-adopted standards.