As anticipated in Chapter 1, Introducing Blockchain Security and Attack Vectors, when we speak generically of blockchain, we actually refer to differing types of technologies united by the fact of storing transaction information within a shared ledger. However, these differences take on significant importance, both in terms of implementation and security.
Therefore, it is important to explore the different characteristics of blockchain-based technologies, with particular regard to public and private (also known as permissioned) blockchains. This will allow us to fully understand the characteristics of Hyperledger Fabric, which represents one of the most popular permissioned blockchain implementations.
So, let's first clarify the distinction between public and private blockchains.