Data parsing is the process of taking structured input, such as a serial message, JSON record, log line, or telemetry feed, and converting it into usable fields a program can act on. A parser reads the format rules, separates values, and interprets them so the receiving system knows what each part means.
In cyber security, parsing matters because it sits at the trust boundary. If input is malformed, unexpected, or maliciously crafted, a weak parser can crash, misread data, or expose bugs such as buffer overflows, injection issues, or logic errors. Defenders use careful parsing to validate inputs, reject bad formats, and avoid stale or misleading output. In constrained systems, like a low-bandwidth serial device receiving external data, disciplined parsing is especially important because every byte must be handled predictably.