Quantum-resistant encryption, also called post-quantum cryptography, uses algorithms intended to stay secure even if large quantum computers become practical. It is designed to protect confidentiality, signatures, and key exchange against the mathematical attacks that could weaken widely used public-key systems.
This matters because attackers can copy encrypted data now and try to decrypt it later, a tactic often called “harvest now, decrypt later.” Long-lived records, certificates, VPNs, APIs, payment systems, and archived files are especially exposed if their cryptography ages out before the data does. Defenders respond by building cryptographic inventories, testing replacement algorithms, updating key management, and coordinating migrations with vendors and legacy systems.