Page 102 - Handbook of Deep Learning in Biomedical Engineering Techniques and Applications

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

(c) Consortium BCes [6]: Private BCs move toward centraliza-
tion of authority by imposing trust limitation (authentication)
on miners who can participate in the consensus mechanism.
The major advantage of private BCs is their scalability and
fine-grained access control. Public BCs have decentralized
control. But they have restrictions on scalability and access
control. Consortium BCs strike a balance between the two.
They are deployed in a decentralized manner on multiple
hardwares managed by different owners. Although member-
ship in consortium-based BCs is private, it is public from
governance perspective. It is a hybrid of public and private
BCs in terms of immutability, transparency, and resource us-
age. Ethermint is an example of this BC.
Currently all the e-governance applications are designed using
public BCs such as Bitcoins. But, consortium BCs are more suit-
able for e-governance applications [7]. This is because such
applications require attributes to balance between public and
private BCs as listed in the following:
• Decentralized control that is not available in private BCs.
• Controlled data reversibility that is possible by publishing the
hash values once the data are changed. In public BCs, data
are immutable as modifying data changes the hash that affects
integrity.
• Data privacy that is facilitated as miners are authenticated and
mining occurs in a trusted environment unlike in the case of a
public BC.
• Transaction volume is scalable as in private BCs. In con-
sortium BCs, validators are known and trusted. This reduces
the complexity of consensus protocol and computational
power while improving the scalability.
• High system throughput and increase in number of transac-
tions per unit time as the complexity consensus protocol in
public BCs is reduced. Consortium BCs also reduce the forking
problem. As the miners are trusted, it encourages the miners to
attach the validated block on the longest chain.
• Ease of protocol updation by reducing the forking problems in
public BCs. This is possible as members in consortium BCs are
well known and hence are able to reach a consensus/
agreement.
This section examined the suitability of consortium BCs for e-
governance applications. An effective consensus mechanism is
essential for decentralized and secure data storage irrespective
of the type of BC. The following section discusses various
consensus mechanisms and suggests a suitable consensus mech-
anism for education domain.