Quantum Attack Risks in Blockchain and Vitalik Buterin’s Proposal

As quantum computers work differently, they change the data security space. The capabilities of quantum computers enable cracking cryptography techniques that a regular computer would need to do for thousands of years. 

As one of our previous articles mentions, the advent of quantum computing does have the potential to create security risks for cryptographic blockchain technologies. The first thing to note is that quantum computers aren’t mainstream yet and haven’t achieved their full potential. 

According to McKinsey, around 5,000 quantum computers will be operational by 2030. Large tech companies like Google and IBM have introduced quantum computers. The machines have complex infrastructure, consisting of a large number of cabling and powerful cooling systems.

To be able to break a cryptographic code, a quantum computer processor would need millions of qubits (a measure of computational power). Today’s largest quantum computer is built by Atom Computing and has 1180 qubits. 

Tech companies announced working on more powerful computers that will be ready in 5 years. While the world is getting there, blockchain doesn’t stay in the same place either. 

To compromise blockchain security and access user funds, a quantum attack would need to achieve 51% network control. In blockchain networks, information is stored in blocks that are linked to each other through cryptographic techniques. If attackers using quantum algorithms take control of most of the network’s computing power, they could change the information as they want. This means they would have the ability to control user assets as they want. 

To perform a 51% attack against large networks using a regular computer is impractical, and doesn’t make sense. If an attacker targets a Bitcoin network, for example, they would need an immense amount of hardware and computational power to compromise the system while new blocks are being added. 

With quantum computers' potential to solve cryptographic problems efficiently, blockchains need new approaches to protect against 51% of attacks. 

As mentioned earlier, there are not enough powerful quantum computers yet to break cryptographic algorithms. Before there was, blockchain security experts have already developed solutions to protect networks from quantum attacks. Among them are quantum-resistant algorithms, and privacy techniques like zk-STARKs. 

Ethereum founder Vitalik Buterin has shared his views about the possible impacts of quantum computing on blockchain many times. Back in 2013, he published an article discussing the need for how to improve Bitcoin’s security and make it quantum-safe. 

Talking about recent developments and possible scenarios, the tech visionary mentioned that Ethereum is already well-positioned to take measures if an emergency attack happens. 

Currently, quantum-resistance cryptography developments such as Account Abstraction and quantum-resistance cryptography are in process. Once they are ready, Ethereum users can switch to the quantum-resistance signature. However, if there is a need to protect user funds, Ethereum can perform a hard fork. Buterin wrote: 

Cybersecurity experts are actively working on ways to safeguard cryptographic infrastructure against potential quantum attacks. Organizations, including the US National Institute of Standards and Technology (NIST) and The Internet Engineering Task Force (IETF), have initiated efforts in post-quantum cryptography. Given the direct connection between quantum computers and crypto, the community of blockchain developers and researchers is preparing for the Q-day. With existing solutions, new developments, and collective technical expertise, the challenges of security have every chance to be effectively addressed.