# Consensus Protocols

Blockchains are distributed databases designed to record, communicate, and transact information without a central authority. Most blockchains are built on a distributed network of individual nodes that work together to provide transactions that take place on the network that they all share. Therefore, every blockchain network needs to have a mechanism that helps ensure all its nodes are synchronized with each other and agree on which transactions are legitimate and should be added to the blockchain. This decentralized system for determining the actual state of the blockchain is called the Consensus Mechanism. In addition to securing the core operations of a blockchain, consensus mechanisms can directly impact the financial and security parameters of the network on which they are based. Most blockchains have three essential attributes: Scalability, Decentralization, and Security – which developers must find a way to encode into the network's algorithmic DNA. The three competing priorities have been dubbed the "Blockchain Trilemma" by Vitalik Buterin, co-founder of Ethereum. Designing and implementing an efficient decentralized network governance model that balances all three attributes is an eternal challenge. As a result, different networks have come up with other blockchain consensus mechanisms that best suit their strategic priorities
