Cardano (ADA) founder Charles Hoskinson (찰스 호스킨슨) publicly criticised Blockstream's push for a "conservative upgrade" approach to countering the threat quantum computers pose to Bitcoin.

On April 22, blockchain outlet The Crypto Basic reported that Hoskinson said Bitcoin is choosing an overly restrictive solution, taking aim at hash-based post-quantum signature methods backed by Blockstream co-founder Adam Back and head of research Jonas Nick.

At the centre of the dispute is an upgrade plan presented at the Bitcoin Scaling Conference OPNEXT 2026. Nick presented hash-based post-quantum signature systems such as "SHRINCS" and "SHRIMPS" as practical alternatives for Bitcoin. He framed quantum-resistant design as a trade-off between efficiency, security assumptions and protocol complexity.

Nick's approach emphasises 2 main points. One is introducing a structure to manage state information to implement a more efficient signature system. The other is accepting some increase in protocol complexity to gain performance improvements. A key point was also to ensure implementation stability by relying on widely vetted hash functions rather than new cryptographic assumptions.

Hoskinson directly criticised that approach. He mocked the idea that Bitcoin, while responding to quantum threats, is trying to choose the "least expressive post-quantum signatures". He said hash-based systems may be suitable for safe transaction signing, but have limited functionality beyond that.

Hoskinson, by contrast, argued that more expressive cryptographic systems can support richer programmability and more complex verification logic. His criticism extended beyond signature methods to Bitcoin's broader development culture. He pointed to what he described as a mindset of "never change Bitcoin". He said a culture that prioritises stability and predictability is blocking more advanced innovation.

The dispute is not limited to Bitcoin. The cryptocurrency industry has continued debating how vulnerable major networks such as Bitcoin, Ethereum and XRP are to advanced quantum computers. In particular, Google researchers recently released an analysis suggesting future quantum devices may require fewer computing resources than previously expected to attack current cryptographic systems.

In Bitcoin, there has also been an estimate that about 1.7 million BTC held in early P2PK wallets could be exposed to quantum attacks. Against that backdrop, developers including Jameson Lopp have recently proposed BIP-361 and moved to strengthen defences in anticipation of a quantum era. Within Bitcoin, cautious change that relies on proven hash functions is gaining support, but Hoskinson is pushing back, saying alternatives with broader usability and long-term scalability are needed.

The issue is less about the quantum threat itself than how to change Bitcoin. The Blockstream camp prefers minimal changes that do not add to security assumptions, while Hoskinson believes a limited approach focused on transaction signatures will struggle to meet future demand. Bitcoin's quantum-response debate appears to be turning into a choice between conservative stability and expanded functionality.

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