Why Quantum Security Is Rising On Layer-1 Roadmaps And Which...

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.

There is also a “harvest now, decrypt later” angle. Adversaries can copy public blockchain data today and wait for quantum hardware to catch up. Once it does, old addresses, long-dormant wallets and some smart contract patterns could become vulnerable even if networks switch to safer algorithms later.

For long-lived public ledgers that cannot be rolled back, quantum planning is becoming an important long-term consideration. With the National Institute of Standards and Technology (NIST) publishing formal post-quantum standards and governments setting 2030-plus migration timelines, layer-1 teams now treat quantum safety as a slow-moving and irreversible risk, and a few networks are already shipping their first countermeasures.

Quantum computers don’t magically “break blockchains”; they target specific algorithms.

Bitcoin, Ethereum and many other chains rely on elliptic-curve schemes (ECDSA and Ed25519) to prove that a transaction came from the holder of a private key. A sufficiently powerful quantum computer running Shor’s algorithm could recover those private keys from their public keys, making it possible to forge signatures and move funds without permission.

Not everything breaks equally. Hash functions like SHA-256 and Keccak are much more robust. Quantum search algorithms such as Grover’s algorithm provide only a quadratic speed-up there, which designers can mostly offset by increasing hash sizes and security margins. The area most likely to need future upgrades is signatures rather than proof-of-work (PoW) hashing or basic transaction integrity.

For blockchains, these areas will require long-term cryptographic upgrades to maintain expected security properties as standards evolve.

Old unspent transaction outputs (UTXOs) in Bitcoin, reused addresses on account-based chains, validator keys and signature-based randomness beac

Source: CoinTelegraph