Quantum computing is often discussed alongside blockchain technology, but usually with a mix of hype and misunderstanding.
The main intersection lies in cryptography:
– **Shor’s Algorithm:** A sufficiently powerful quantum computer running Shor’s algorithm can break asymmetric encryption schemes based on integer factorization (RSA) and discrete logarithms over elliptic curves (ECDSA, used in Bitcoin and Ethereum).
– **Grover’s Algorithm:** Speeds up brute-forcing symmetric encryption and hash functions (SHA-256), effectively reducing security margins by half (SHA-256 security drops to 128 bits).
**The Solution:** Post-Quantum Cryptography (PQC).
Lattice-based cryptography (like CRYSTALS-Dilithium and Falcon) provides quantum-resistant signature schemes that can replace ECDSA before quantum supremacy threatens public blockchain ledgers.
The migration to post-quantum standards is already underway in major security protocols.
