What is a Public Blockchain?

By Julia Cook
Published Jun 17, 2022 and Updated Mar 21st, 2023

A public blockchain is a truly decentralized blockchain that is open for anyone to join and to verify and read all transactions that occur within the public network.

A public blockchain is a fully decentralized, consensus-based blockchain network that requires cryptocurrency to pay for transaction fees, and in most cases also offers a Bitcoin (BTC) or altcoin incentive to mining nodes as an incentive for them to participate in the process. This is necessary due to the high energy and RAM consumption that hashing requires on a public blockchain.

The reason that these are so high is because of the extensive amount of data stored on the blockchain and the difficulty that may be associated with the hashing, as is the case with the Bitcoin blockchain SHA-256 protocol.

True public blockchains are open access and permissionless, meaning that any node can join the blockchain, access its data and engage in validating, hashing, transacting and mining activities on the blockchain. Furthermore, all nodes on the network are anonymous, as in order to join the blockchain network, all they need is to acquire a crypto wallet that will serve as their public key on the blockchain.

The e-wallet name is usually a randomly generated series of numbers and letters, as is the password. This makes it almost impossible for the e-wallet to be hacked into. Therefore, neither the owner’s location nor real name is known to other users. But all of their transactions on the network are visible to all on the network. As is all other data stored and transacted on the blockchain.

Furthermore, because public blockchains are open to everyone, they can have thousands or even millions of nodes connected to them. This means that hacking into the network and altering data on the basis of consensus is nearly impossible, since at least 51% of nodes would need to be hacked and approve the transaction or other alteration simultaneously. This should make the blockchain ledger system far more secure and reliable than most other forms of data storage.