What is Mina Protocol Network
The first cryptocurrency ever developed using succinct blockchain technology, Mina Protocol (formerly Coda Protocol) offers payment functionality similar to Bitcoin, with a dramatically faster verification time of 200ms making it practical for lightweight clients and mobile devices to perform full verification of the system’s history. Mina's goal is to design a decentralized payment system that offers efficient verification of system history from genesis without relying on any external advice. Specifically, they aim to provide a verification time constant in the number of transactions, called a succinct blockchain by including succinct proofs of state validity in each block. In particular, Mina uses an account-based model like Ethereum. Instead of the UTXO model like Bitcoin and others where the current state of the blockchain is a list of all account balances rather than a list of unspent coins. Each block contains a commitment to this state (in a Merkle tree) and not the entire state. So a full node doesn’t need to store the entire state but can verify account balances just as efficiently, with only the information in the latest block header. However, a prover in the system (roughly equivalent to a miner in Bitcoin) does need to store the full state since it is part of the witness when proving the validity of new blocks.
Mina's Consensus Protocol
The consensus protocol of Mina is developed as the first provably-secure proof-of-stake (PoS) consensus protocol for succinct blockchains called “Ouroboros Samasika”. Note that an off-the-shelf consensus mechanism is not necessarily compatible with a succinct blockchain framework, since the way consensus is achieved when there are multiple contending chains could rely on arbitrary transaction history, forcing nodes to store the entire transaction history. In fact,