A protocol is a system of rules for communication between independent systems.
Protocols are often thought of as decentralizing: anyone who follows the protocol can be part of the network. The reality is usually more complicated.1
Nathan Schneider, “Decentralization: An Incomplete Ambition,” Journal of Cultural Economy 12, no. 4 (July 4, 2019): 265–85, https://doi.org/10.1080/17530350.2019.1589553; Alexander R. Galloway, Protocol: How Control Exists after Decentralization, 1. MIT Press paperback ed, Leonardo (Cambridge, Mass.: MIT Press, 2006).