Are smart contracts smart enough to survive a quantum future?

Smart contracts are immutable. Automated. Brilliant.

But are they quantum-resistant?

Not really. The majority of smart contracts use the same cryptographic fundamentals as the remainder of blockchain (ECDSA, RSA and standard hashing algorithms). They execute logic without human input, yet still rely on security assumptions from classical cryptography.

Well, when the quantum computers of a higher time frame come out of the lab and start pumping up Shor’s algorithm, what would happen?

Smart contracts with public keys that are exposed could be attacked.

Contracts’ private keys can be easily reverse-engineered.

The same immutability and trustlessness that first attracted us to decentralised smart contracts may make these harder to upgrade in a post-quantum world. Frozen contracts with old crypto is basically an unpatchable vault.

At some point in the decades-long run-up, at least one of those “science-fiction solutions” had better come through lattice-based signatures, hash-based schemes, or post-quantum cryptographic primitives that exist over large enough fields. However, until smart contracts have become standardized and activated, most are sitting on a ticking time bomb of security vulnerabilities.

Smart contracts are only as smart as the crypto that underpins them. And many of them will look dumb in a quantum future.