Grover's Algorithm

Lov Grover's 1996 quantum search algorithm giving a quadratic speedup against symmetric ciphers and hash functions.

Core Principles & Analysis

• Halves the effective key length of symmetric ciphers — AES-128 degrades to roughly 64-bit security.
• The standard prescription is simply doubling key sizes: AES-256 and SHA-384 stay comfortable.
• Its quadratic speedup is provably optimal for unstructured search — no better quantum attack exists.

Specifications & Metrics

• TYPE: Quantum algorithm
• STATUS: Awaiting hardware
• YEAR: 1996