public blockchain is that no one individual or company is able to control the information which is contained on the blockchain or the rules governing the blockchain. It is not possible for the owner of the blockchain to change the rules of the blockchain at his own wish.
The public blockchain, is exactly what the name suggest, Blockchain technology that is completely open to the public,namely anyone able to join to the network as a participator. Which growing number of the participants in network. A private blockchain network requires an invitation and must be validated by either the network starter or by a set of rules put in place by the network starts