Coinbase Releases Draft Specification for SHRINCS
The proposed signature scheme seeks to protect Bitcoin from quantum threats but remains in the early research phase.
Updated on Oct. 21, 2026 in Quantum Computing
Live Poll
Do you trust that new security updates for digital assets will keep your personal funds safe?
Coinbase has released a draft specification named SHRINCS, which aims to provide quantum-resistant signatures for the Bitcoin network. The proposal is currently in the research-stage, lacking final security proofs or optimized implementations.
Why it matters
As quantum computing threatens existing cryptographic standards, Coinbase is developing methods to secure its custody business, which holds 12% of all Bitcoin. This draft represents a move toward infrastructure preparation for post-quantum transaction signing.
The SHRINCS scheme utilizes a 48-byte public key to generate signatures, with stateful versions offering a 548 to 4,619 byte footprint. A stateless fallback path, derived from the hash-based SLH-DSA standard, generates a 5,777-byte signature.
The players
Coinbase
A centralized digital asset exchange providing custody services for approximately 12% of the global Bitcoin supply.
Shashank Agrawal
A researcher who published the requirements for the SHRINCS protocol.
Brian Armstrong
The chief executive officer of Coinbase who advocated for collaborative quantum readiness.
The details
SHRINCS uses sectorization, a process that divides signing space into distinct, non-overlapping parts managed by separate hardware devices. To prevent forgery, stateful signing relies on preventing the reuse of one-time signing slots; the system requires persistent recording of counter increments before a signature is returned. If a trustworthy state record is unavailable, such as after a backup restoration, the protocol falls back to a larger stateless hash-based signature.
Timeline
September 2026: RFC 10033 cataloged approaches for stateful signing management.
October 13, 2026: Shashank Agrawal published the SHRINCS requirement details.
October 20, 2026: Brian Armstrong called for industry-wide collaboration.
The Tech Race
SHRINCS functions as an extension of the methodologies cataloged in RFC 10033 regarding stateful signing. This effort marks a deliberate shift toward creating quantum-resistant standards for the Bitcoin network before current cryptographic methods face obsolescence.
This draft is a research-stage proposal and does not currently affect Bitcoin transactions for individual users. Implementation would eventually impact node operators and custodial services that must manage stateful keys for signing.
The takeaway
The industry must now monitor the development of security proofs and optimized code for SHRINCS to determine its viability for mainnet adoption. Future milestones include demonstrating system behavior during server replacement and interrupted write cycles.
Further reading
For broader context on current developments, visit our section on Quantum Computing.
Live Poll
Do you trust that new security updates for digital assets will keep your personal funds safe?
