Page 101 - Handbook of Deep Learning in Biomedical Engineering Techniques and Applications

Chapter 4 A critical review on using blockchain technology in education domain 89

2. Consortium blockchain and its suitability
for e-governance

Based on the privacy, BCs can be classified as follows (Table 4.1):
(a) Permissioned or private BCs: Permissioned BCs impose
restrictions on the set of users who can validate transactions.
They restrict access to approved actors who can create smart
contracts. Hyperledger Fabric is a permissioned BC.
(b) Permissionless or public BCs: In such BCs, any participant
can participate in consensus, as well as create smart
contracts. Bitcoin and Ethereum BCs are good examples of
this type.

Table 4.1 Comparison of private, public, and consortium blockchains.

Blockchain Consortium
type Private blockchain Public blockchain blockchain

Consensus By a single node; permissioned By all nodes; permissionless By a set of nodes;
management permissioned
Infrastructure Centralized Distributed Decentralized
control
Validation List of authorized nodes By any node List of authorized nodes
Scalability More Less More
Fine-grained Allows fine-grained control by Not possible to ensure Restricts access to a
control restricting access to a few fine-grained control group
participants
Transactions High (few thousand validated per Low (few transactions per Medium (few hundred
throughput second) second) transactions per second)
Data Yes, but rollback is possible Yes, but rollback is Yes, but rollback is
immutability impossible possible
Access control Read is restricted to authorized Permissionless: Anyone can Read, write, and commit
users; write and commit is read, write, and commit are restricted to
restricted to network operators Permissioned: Anyone can authorized participants
read; only authorized can
write and commit
Centralized Yes No Partial
control