As Bitcoin researchers discuss how blockchain can be strengthened against the disruptive threats that quantum computers may pose in the future, “hash-based signatures” stand out as a significant potential solution.
Because quantum computers have the potential to break classical cryptography, this is seen as one of the biggest security risks to the blockchain ecosystem.
Quantum computers, thanks to the advantages provided by quantum mechanics, can solve certain mathematical problems many times faster than classical computers. This means that the cryptographic structures that form the basis of blockchains like Bitcoin could be compromised in the future.
In an updated study published on December 5, Blockstream researchers Mikhail Kudinov and Jonas Nick examined various methods that could be implemented to make the $1.8 trillion Bitcoin network resilient to quantum attacks. The duo argued that hash-based signatures are one of the most attractive options because their security is based on the hash functions already used in Bitcoin's design.
Announcing the study on the Bitcoin developer email list, Kudinov said, “These schematics have undergone extensive analysis throughout NIST’s post-quantum standardization process, which increases confidence in their robustness.” The National Institute of Standards and Technology (NIST), a U.S. government agency, is known for setting cybersecurity standards used worldwide.
Although academics have long disagreed on when quantum computers will threaten Bitcoin, recent developments have revived the debate. In February, Microsoft introduced a new chip that it claims solves the scaling problem of quantum computers. In October, Google published research showing that quantum computing is much closer to real-world applications.
Pierre-Luc Dallaire-Demers, a scientist from the University of Calgary, says that at the current rate of progress, Bitcoin could become vulnerable to the threat of quantum computers within the next 5 to 10 years. Ethereum co-founder Vitalik Buterin, however, is concerned about a much earlier timeline; according to Buterin, Ethereum's security model could be compromised even before the 2028 US presidential election.
Hash-based signatures rely on hash functions, which are mathematically considered resistant to quantum attacks. Unlike Bitcoin's public-key cryptography, hash functions are far more resistant to quantum algorithms like Shor. Furthermore, the outputs of hash functions can be expanded to render the brute-force search capabilities of quantum computers meaningless.
However, it is not yet clear how this method will be applied to Bitcoin. Critical issues such as verification costs, whether multiple hash-based signature standards will be supported, and whether transaction verification will require the entire blockchain history are still being debated among developers.
*This is not investment advice.
