Figure 1.11: Types of Blockchain

Public Blockchains are often permissionless or open for all, i.e., one

does not need the permission of any authority to join them. The

original Bitcoin Blockchain network is such an example. Some public

Blockchains are also public permissioned. But the private DLTs are

mostly permissioned or built with only trusted parties or participants,

and hence their consensus models are also of different types.

Obviously, they are used for different types of use cases.

1.9 Does your Use Case need a Blockchain?

So far, the reader got some exposure to the Blockchain and the

magic that it can create. So, if a Blockchain is that charismatic, then

why are the big players not replacing their existing databases to

Blockchain? The answer is simple. A Blockchain might be a brand

new out-of-the-world framework, but it is not meant to address all

kind of storage requirements. Let’s find out where it works and where

it doesn’t.