Understanding The Quorum Ecosystem

Before Moving On:

For Introduction on Quorum you can refer to official quorum documentation, which can be a bit too technical, for just understanding the flow of quorum I would suggest you to first go through  my blog Introduction To Quorum Blockchain to be familiar with the idea of quorum with simple explanation and then you can go straight into the official quorum documentation at quorum wiki.
After a good read on above-mentioned wiki and blog, let’s get straight into it and let’s be familiar with the quorum ecosystem which supports the protocol of the blockchain.
Quorum Architectural Components:

Quorum currently following components:

1. Quorum Node (modified Geth Client)

2. Constellation/Tessera - Transaction Manager

3. Constellation/Tessera - Enclave

Quorum Architectural Component Diagram [Source]

1. Quorum Node:-

Quorum node is an implementation forked from already famous and in use go-ethereum node but:
- Its lightweight and has a different consensus mechanism (Voting based Consensus Istanbul or RAFT) than POW of Ethereum.

- It only allows connection from permission nodes

- The block validation logic has been changed from ‘global state root’ to ‘global public state root’ what it means is that instead of changing the ledger state for each transaction made on blockchain only public transactions are committed as publicly open on all nodes and private transaction’s validation will be skipped by parties not parting in the transactions.

- Block validation logic now can handle private transactions also allow encrypted transaction data in place of actual transaction data in case of private transactions. Also,

- Gas pricing is completely removed yet Gas is still required but in low amounts.

2. Constellation/Tessera: Transaction Manager & Crypto Enclave:-
Constellation and Tessera are Haskell and Java implementation for the system to submit information in a secure way using encryption and public and private key pairs. Works like message delivery client but providing info in an encrypted manner, so can also be used in any other scenario where information is needed to be exchanged in encrypted format among the interested parties as these are not specific to blockchain protocol itself. Two sub-modules of constellation/tessera:
 

a. Transaction Manager

b. The Crypto Enclave
 

Transaction Manager:
They allow access to their stored encrypted private transaction data and exchange this encrypted transaction data with all other registered transaction managers. It makes use of Crypto Enclave for encrypting and Decrypting private transaction data.

The Crypto Enclave:
It's a cryptographic suite of Quorum which provides an efficient implementation for handling all the cryptographic operations as well as public and private key generations.