A signature candidate is a proposed digital signature scheme that is still being evaluated before standardization. It may be a new design, a revised parameter set, or a post-quantum alternative meant to replace older signing methods. While it is under review, its security claims are provisional and depend on the exact version, threat model, and implementation.
This matters because attackers often look for weaknesses before a scheme becomes widely deployed. They may target the math behind the design, the chosen parameters, or coding mistakes in real implementations. For defenders, the key lesson is to treat candidate schemes as research subjects, not finished security guarantees. Teams should track which standard or draft is actually in use, test implementations carefully, and follow cryptanalysis closely so that a flaw is caught before deployment or migration.