The Blockstream researcher proposes SHRIMPS, a post-quantum signature scheme with signatures of approximately 2.5 KB compatible with multi-device configurations.
Jonas Nick, Bitcoin researcher at Blockstream, has presented SHRIMPS, a post-quantum (PQ) signature scheme designed to support secure signing across multiple devices while maintaining relatively compact signature sizes. The proposal was published on March 30, 2026, and fits into the ongoing debate on quantum resistance in cryptographic systems, including Bitcoin.
From a technical standpoint, SHRIMPS is a hash-based construction that allows multiple devices initialized from the same seed to generate signatures independently. The resulting signatures are typically around 2.5 KB in size at a 128-bit security level. The proposal builds on previous work such as SHRINCS, which produces smaller signatures but is limited to a single-device configuration due to state management constraints.
SHRIMPS is designed to remove this limitation, enabling independent signing across multiple devices while keeping security within a predefined bound. The approach assumes an upper limit on the number of devices derived from a single seed, which helps preserve the integrity of the scheme. Technically, the construction combines two SPHINCS+ instances under a single public key: a compact signing path is used for initial signatures, while a fallback path supports additional uses, allowing the system to balance efficiency and flexibility.
Comparing SHRIMPS with stateless alternatives such as SLH-DSA, where signatures can reach approximately 7.8 KB, the advantage in terms of compactness is clear. The proposal also outlines a hybrid model with SHRINCS, in which a primary device can generate smaller signatures while backup devices use SHRIMPS to maintain multi-device functionality. The design could find application in systems such as Bitcoin wallets, where keys are typically used for a limited number of signatures and multi-device configurations are common.
The research comes at a time of renewed discussion around quantum computing and its potential long-term impact on cryptographic systems, including Bitcoin. While practical quantum attacks are still considered years or decades away, research into post-quantum signatures continues to explore ways to mitigate theoretical risks. Separately, as reported by Atlas21 in a recent article on the topic of quantum computing and Bitcoin, a widely circulated post highlighted that a co-author cited as a “Bitcoin security researcher” is affiliated with the Ethereum Foundation, raising questions about the neutrality of conclusions regarding alleged vulnerabilities in Bitcoin’s cryptography.
