TL;DR

Charles Hoskinson criticizes Bitcoin’s post-quantum strategy, arguing that the choice of SPHINCS+ is too limited in expressiveness and could restrict long-term protocol evolution.
He says Bitcoin prioritizes security minimization over flexibility, which may reduce future scalability and composability options.
Bitcoin developers defend the approach, emphasizing simplicity and reduced attack surface, while quantum threats remain theoretical but actively discussed.

Charles Hoskinson has intensified the debate around Bitcoin’s Post-Quantum Strategy after questioning the selection of SPHINCS+ as a long-term defense against potential quantum computing threats. The Cardano founder argues that the decision reflects a conservative engineering mindset that may limit future adaptability. His comments arrive as the crypto sector continues evaluating how to prepare blockchain systems for theoretical quantum risks without undermining efficiency or usability.

Lol, let's use the least expressive and interesting PQS to solve the quantum issue. Never change Bitcoin https://t.co/2mcytWyb12

— Charles Hoskinson (@IOHK_Charles) April 21, 2026

Bitcoin’s Post-Quantum Strategy And The SPHINCS+ Debate

SPHINCS+ is a hash-based signature scheme designed to resist quantum attacks. While it is considered highly secure, Hoskinson argues that it is not sufficiently expressive for broader blockchain use cases. He claims Bitcoin is prioritizing a narrow security model over extensibility, which could limit capabilities such as advanced scripting and composability. From his perspective, SPHINCS+ solves a specific cryptographic problem but does not expand the protocol’s functional design space.

Bitcoin developers maintain a different view. They argue that simplicity is a core security feature, and that avoiding complex mathematical structures reduces systemic risk. In this context, SPHINCS+ is attractive because it relies on well-understood hash functions rather than newer or more experimental cryptographic assumptions. This conservative design philosophy has historically shaped Bitcoin’s reliability and resilience.

Scalability Trade Offs And Long Term Design Choices

A key concern raised in the debate is the large signature size of SPHINCS+, which is significantly bigger than current schemes like ECDSA or Schnorr signatures. Critics argue this could increase transaction data size and create long-term scalability pressure. Hoskinson suggests that committing to a rigid post-quantum standard now may reduce flexibility if more efficient alternatives emerge in the future.

Bitcoin’s current cryptography remains secure against known quantum computing capabilities, as such machines do not yet exist at the required scale. Still, research into post-quantum systems continues across the industry. Meanwhile, Bitcoin trades in a stabilization phase near the upper $70,000 range, reflecting a market that is consolidating while regulatory and technological discussions evolve.

The disagreement reflects two competing design philosophies. One prioritizes maximum security with minimal complexity, while the other emphasizes adaptability and long-term extensibility as technology evolves.