[DigitalToday reporter Yoonseo Lee] As the quantum computer threat emerges as a long-term security challenge for the blockchain industry, bitcoin and ethereum are choosing different response strategies.

Cointelegraph reported on April 20 that bitcoin is placing more weight on a gradual response that preserves its existing structure as much as possible, while ethereum is detailing a roadmap to change the network step by step.

The key issue is that both networks rely on a public-key cryptosystem. Elliptic Curve Cryptography (ECC) is widely used for blockchain wallets and transaction signatures. If sufficiently powerful quantum computers emerge, it has been raised that methods such as Shor's algorithm could make it possible to derive private keys from public keys. In that case, wallet ownership and transaction verification systems could be shaken.

The threat has not become reality yet. Most researchers believe it could still take years to decades for quantum computers capable of breaking encryption in practical terms to appear. The problem is that blockchain networks cannot be changed immediately like general services. A large-scale transition requires long coordination, testing and user adoption. That can be described as a situation that is "not urgent right now, but preparations need to start much earlier."

The discussion is spreading beyond the cryptocurrency industry to major technology companies. Google set a goal in March 2026 to convert its systems to quantum-resistant cryptography by 2029. It warned that existing encryption and digital signatures could be threatened by quantum computers. The discussion is more sensitive in blockchain, where digital signatures are key to verifying asset ownership.

So how are bitcoin and ethereum preparing, respectively?

Bitcoin is seeking solutions that prioritise minimal changes and stability. A frequently cited solution is BIP-360, which includes the concept of Pay to Merkle Root (P2MR). Rather than overhauling the entire cryptosystem, it adjusts certain transaction output structures to reduce public key exposure. The goal is not to secure full quantum resistance all at once. The focus is on creating a path to move to safer transaction types while maintaining compatibility with existing systems.

This approach aligns with the bitcoin community's conservative operating philosophy. Bitcoin tends to allow upgrades only to the extent that they do not undermine decentralisation and predictability. Critics of this cautious stance also say that if quantum technology advances faster, the response could be delayed. At the same time, concerns have been raised that hasty changes could harm long-term security.

Ethereum has moved toward a more pre-emptive and structured response. The ethereum ecosystem is organising a roadmap that treats the shift to quantum resistance not as a single technical tweak but as a multi-layer system upgrade task. The key concept is "cryptographic agility". It means the ability to replace core cryptographic components without harming network stability.

The roadmap reviews multiple layers. In the execution layer, it is looking at account abstraction and alternative signature methods. In the consensus layer, it is evaluating ways to change validator signature mechanisms to hash-based methods and the like. In the data layer, it is discussing ways to adjust data availability structures to maintain security even in a quantum environment. Developers are placing this task as a long-term strategic priority, with the timing also in mind through the late 2020s.

The differences between the two networks go beyond a simple technical choice and diverge in structure and governance. Bitcoin prioritises the solidity and predictability of the base layer and applies a high consensus threshold to large changes. Ethereum, by contrast, has experience in actually 추진해 온 complex upgrades such as its transition to proof of stake (PoS) and scalability improvements. Accordingly, bitcoin is summarised as viewing the quantum threat as a "distant risk requiring minimal intervention", while ethereum sees it as a "system-level task requiring early design."

Neither side has finalised a solution yet. Bitcoin is reviewing various proposals but has not adopted an official transition path. Ethereum is ahead in planning, but technical hurdles and community coordination tasks remain before actual implementation. Common tasks include how to move assets protected by existing vulnerable cryptography, how to coordinate upgrades in a decentralised community, and how to balance backward compatibility with future security.

In this situation, the likelihood that the market will react immediately in prices is limited. That is because the quantum threat is still seen as a long-term issue. Still, as institutions begin to seriously review related threats, it has been raised that each network's level of preparedness and adaptability could later be reflected in long-term trust assessments.