# Ali Estimates Post-Quantum Signatures Could Cut Bitcoin Capacity 10-Fold By Simon Yoon Canonical URL: https://www.tokenpost.com/news/technology/40654 Published: 2026-10-25T19:15:26.000Z Updated: 2026-10-25T19:15:26.000Z Section: Technology > Stacks posted Ali’s Oct. 8 keynote recording on Oct. 23. Bitcoin’s related upgrade proposals remain drafts. A newly released keynote from Stacks co-founder Muneeb Ali puts a possible 10-fold drop in Bitcoin’s block capacity at the center of the post-quantum security debate, illustrating the cost of larger signatures. Stacks posted Ali’s full keynote from TOKEN2049 Singapore on Oct. 23, after his conference presentation on Oct. 8. His roadmap for Stacks through 2030 covers Bitcoin-focused capital markets, privacy and post-quantum security. It presents Stacks as an additional layer for activity that might otherwise use Bitcoin’s block space. Ali estimated that adopting quantum-resistant signatures could leave Bitcoin with roughly one-tenth of its current transaction capacity. The figure points to a potential trade-off: larger signatures could leave room for fewer transactions in each block. It is an estimate, not a measured change in Bitcoin throughput. Signature size is one factor behind the estimate. Bitcoin’s Schnorr signatures are 64 bytes, while ML-DSA-44, a post-quantum signature standard, is 2,420 bytes. Those figures describe the signatures themselves, not complete transactions. A modeled scenario estimates that a block could hold about 4,200 transactions using Schnorr signatures, compared with about 84 using a 2,420-byte signature. Under a separate assumption using a 324-byte SHRINCS signature, the estimate is about 1,750 transactions per block. These figures are scenarios, and estimates vary with the signature design. Bitcoin uses ECDSA as well as Schnorr signatures. A sufficiently capable quantum computer could threaten these elliptic-curve systems, while replacing them with post-quantum signatures could increase transaction data. The network’s eventual capacity impact would depend on the design it adopts. The [draft status of Bitcoin’s quantum-security proposals]() leaves the design and timing open. BIP-360 proposes a Pay-to-Merkle-Root output format but does not add post-quantum signatures. BIP-361 describes a migration approach that depends on a future proposal for those signatures. Neither establishes an adopted scheme or a migration schedule. Ali summed up the broader Stacks vision: “Bitcoin won the argument as money. The next decade is about Bitcoin as capital.” The U.S. National Institute of Standards and Technology (NIST) plans to remove quantum-vulnerable algorithms from its standards by 2035, with higher-risk systems transitioning sooner. That timetable concerns cryptographic standards; it does not set a schedule for Bitcoin. ## Links in this article - [draft status of Bitcoin’s quantum-security proposals](https://www.tokenpost.com/news/technology/39613)