KSC-Letter is a cryptographic communication protocol that encodes information exclusively in the temporal domain, in which symbols are transmitted through the precise instant of occurrence of discrete pulses, independently of the physical medium used for event emission or detection. The protocol operates as a deterministic state machine driven by multiple evolving sequences of prime numbers, whose states are processed through cascaded non-linear functions to produce a unique cryptographic value for each discrete instant of time. From a previously shared secret seed, the communicating parties independently generate an ephemeral temporal mapping that associates specific time instants with symbols of a finite alphabet, allowing message transmission through events occurring at cryptographically determined minutes. The system architecture is designed to provide operational blindness to human operators and separation of knowledge between operators and the system implementer, reducing the impact of partial protocol compromise. A formal model of the system is presented, and its informational and computational security properties are discussed, including resistance to traffic analysis, plausible deniability, tolerance to false pulses, and operation under extreme bandwidth constraints. The work demonstrates the feasibility of communication channels based exclusively on temporality as a primary cryptographic mechanism, proposing an alternative architecture for secure and covert communication in environments of intensive surveillance or severe operational restrictions.
KAUÊ BASSO (Sun,) studied this question.