The formal set of rules that define how participants in a network communicate and reach consensus.
A protocol specifies message formats, validation rules, and consensus procedures. In cryptocurrencies, it governs transaction validity, block structure, and upgrade mechanisms.
"Bitcoin Cash’s protocol defines how transactions are formed, how blocks are validated, and how nodes agree on the canonical chain."
Protocols evolve via proposals, testing, and network-wide upgrades. Backward-compatible changes are soft forks; incompatible changes are hard forks.
"A block size limit change typically requires a coordinated protocol upgrade."
All terms and definitions may update as the Cryptionary improves.