Charles Hoskinson questions Bitcoin’s post-quantum security approach

Bitcoin’s move toward post-quantum security has drawn criticism from Cardano founder Charles Hoskinson, who questioned the design choice behind the proposed protection model

Summary

• Hoskinson said Bitcoin chose SPHINCS+, a quantum-resistant signature scheme with limited flexibility and larger transaction sizes.
• Bitcoin developers appear focused on security and simplicity rather than broader functionality in post-quantum upgrade planning.
• The debate reflects tension between defensive design choices and future flexibility in Bitcoin’s slow upgrade cycle.

His comments focused on SPHINCS+, a hash-based signature scheme that some developers view as a safe option against future quantum threats.

Hoskinson said Bitcoin may be choosing the “least expressive and interesting” post-quantum signature system. His remarks centered on flexibility, arguing that the selected approach may protect the network but offer little room for broader functionality.

SPHINCS+ draws attention in Bitcoin debate

SPHINCS+ is a stateless hash-based signature scheme designed to resist attacks from quantum computers. It does not rely on complex mathematical structures, which makes it attractive to developers who prefer simple and defensive security tools.

That design also comes with trade-offs. SPHINCS+ signatures are much larger than current ECDSA or Schnorr signatures, which can increase transaction size and put pressure on scalability if adopted widely.

Moreover, Hoskinson’s criticism focused on what he described as a missed chance for a wider upgrade. He argued that Bitcoin could adopt a post-quantum system that does more than solve one security issue.

His concern was not about quantum resistance alone. He questioned whether Bitcoin should lock itself into a rigid system now, especially when other post-quantum options may become more adaptable in the future.

Bitcoin developers remain focused on caution

Bitcoin developers have often favored conservative changes that reduce attack risks. From that view, SPHINCS+ fits the network’s long-standing design style because it depends on simple hash functions and avoids added complexity.

That approach suggests Bitcoin is treating post-quantum protection as a defensive update rather than a feature expansion. For developers who value stability over added capability, that may remain the stronger argument.

Meanwhile, large-scale quantum computers cannot yet break Bitcoin’s current cryptography. Even so, the discussion has gained traction as more blockchain projects begin planning for long-term security changes.

Bitcoin’s slow upgrade cycle means any decision made now could stay in place for years. That has turned the debate into a broader question about whether the network should prioritize immediate caution or future flexibility.