SHA-256
A 256-bit cryptographic hash function used for integrity, commitments and Bitcoin's proof-of-work. Like AES, it is weakened but not broken by quantum computing — Grover's algorithm reduces collision-finding effort quadratically, which larger outputs absorb.
Related terms
A quantum search algorithm that finds an item in an unstructured set of N in roughly √N steps. Against symmetric cryptography this halves effective key strength — a nuisance answered by doubling key sizes, not a break.
A signature scheme built only from hash functions, with no number-theoretic or lattice assumptions. Security reduces to the collision and preimage resistance of the hash, which is unusually well understood.
A consensus mechanism where miners expend computation to add blocks. Quantum computers threaten blockchain signatures rather than proof-of-work — Grover's algorithm offers only a modest mining advantage, not a break.