Quantum security is moving from theory to practice as layer-1 blockchains prepare long-term plans to adopt post-quantum cryptography.
Quantum computers still look like lab toys: Racks of hardware, error-prone qubits and almost no real-world applications. Yet if you check the roadmaps of major layer-1 blockchains, a new priority now sits next to scaling and modularity: post-quantum security.
The concern is simple even if the math isn’t. Most major blockchains rely on elliptic-curve signatures (ECDSA and Ed25519) to prove that a transaction came from the owner of a private key. A sufficiently powerful quantum computer running Shor’s algorithm could, in theory, recover those private keys from their public counterparts and let an attacker sign fake transactions.
