Post-Quantum Bitcoin Research Expands With New Signature Schemes and Recovery Prototypes

Ongoing research into quantum-resistant Bitcoin systems has produced several new proposals and early-stage implementations, reflecting continued efforts to address long-term cryptographic risks.

Jonas Nick, a researcher at Blockstream, recently introduced SHRIMPS, a proposed post-quantum signature scheme designed to support secure transaction signing across multiple devices while maintaining relatively compact signature sizes.

Nick described SHRIMPS as a hash-based scheme enabling multiple devices from the same seed to generate ~2.5 KB signatures. 

It builds on SHRINCS, which is limited to single-device use, by supporting multi-device signing within defined security bounds.

The design combines two SPHINCS+ instances with primary and fallback paths, producing smaller signatures than some stateless alternatives like SLH-DSA (~7.8 KB), and supports hybrid setups using SHRINCS for primary devices and SHRIMPS for backups. 

It is intended for use cases like Bitcoin wallets with multi-device configurations.

Separately, Avihu Levy introduced a proposal titled “Quantum-Safe Bitcoin Transactions Without Softforks,” outlining a method for constructing quantum-resistant Bitcoin transactions using existing consensus rules.

Levy’s approach, referred to as Quantum Safe Bitcoin (QSB), replaces reliance on elliptic curve cryptography with hash-based constructions.

The design aims to mitigate risks posed by quantum algorithms such as Shor’s algorithm, which could theoretically break ECDSA by solving discrete logarithms.

The proposal builds on earlier work known as Binohash and introduces a “hash-to-signature” puzzle, where transaction validity depends on hash pre-image resistance rather than elliptic curve assumptions.

This design relies on cryptographic hash functions such as RIPEMD-160, making it resistant to quantum attacks that target elliptic curve systems.

QSB operates within Bitcoin’s existing constraints, including opcode and script size limits, but produces non-standard transactions that may require direct submission to miners. 

The computational cost for constructing such transactions is estimated to range between $75 and $150 using GPU resources.

In parallel, Olaoluwa Osuntokun has developed a prototype focused on wallet recovery in a post-quantum scenario. 

The system uses zk-STARK proofs to allow users to demonstrate ownership of a wallet derived from a seed phrase without revealing the seed itself.

The prototype is designed to address a limitation in some proposed emergency upgrade scenarios, where older wallets could become inaccessible if legacy signature schemes are disabled. 

The system generates proofs in under a minute on consumer hardware, with verification completed in seconds and proof sizes around 1.7 MB.

Osuntokun stated, “proposals to make Bitcoin Post Quantum secure are actively being researched, discussed and developed by Bitcoin developers all around the world.”

The developments come amid increased discussion around quantum computing and its potential impact on Bitcoin’s cryptographic foundations. 

While practical quantum attacks are still considered years or decades away, multiple approaches, including hash-based signatures, hybrid schemes, and zero-knowledge recovery mechanisms, are being explored in parallel.

Commenting on the pace of development, JAN3 CEO Samson Mow wrote, “Bitcoin defenses against non-existent quantum computers is moving along at an incredibly fast pace. There’s also the prototype from @roasbeef too. RIP QC FUD.”

Together, these proposals and prototypes reflect a growing body of research aimed at improving Bitcoin’s long-term resilience while navigating the technical and coordination challenges of upgrading a decentralized system.