Quantum Resistance

Blockchains such as Bitcoin and Ethereum rely on cryptography to secure their networks. They do this with a system of private keys, held by the user and used to authorize transactions, and public keys, which allow others on the network to verify their signatures. However, given a sufficiently powerful computer, it is theoretically possible to derive a user’s private keys from their public keys.

The concern is that quantum computers will soon be powerful enough to do just that, fundamentally breaking the cryptographic security that blockchains rely on. Bitcoin's elliptic curve signatures and Ethereum's transaction signatures are among those potentially vulnerable.

Quantum-proofing is the process of updating networks and protocols to prepare for the rise in quantum computing. Post-quantum cryptography, championed by the U.S. National Institute of Standards and Technology (NIST), aims to address the risks by developing new algorithms complex enough to resist attacks from quantum computers.

Quantum-resistant cryptography upgrades feature on the development roadmaps of many leading blockchains; many leading figures place the deadline for these upgrades around the year 2030, with some predicting that ‘Q-Day’ could arrive even sooner. Any such updates could require significant protocol overhauls, including changes to transaction signatures and wallet infrastructure. They may also require users to migrate their holdings to new quantum-proof addresses.