Mastering Blockchain - Second Edition

CAP theorem and blockchain

CAP theorem, also known as Brewer's theorem, was introduced by Eric Brewer in 1998 as conjecture. In 2002, it was proven as a theorem by Seth Gilbert and Nancy Lynch. The theory states that any distributed system cannot have consistency, availability, and partition tolerance simultaneously:

• Consistency is a property which ensures that all nodes in a distributed system have a single, current, and identical copy of the data.
• Availability means that the nodes in the system are up, accessible for use, and are accepting incoming requests and responding with data without any failures as and when required. In other words, data is available at each node and the nodes are responding to requests.
• Partition tolerance ensures ...