Page 115 - Handbook of Deep Learning in Biomedical Engineering Techniques and Applications

Chapter 4 A critical review on using blockchain technology in education domain 103

Table 4.4 Comparison of consensus protocols.dcontinued
Consensus Smart Suitability for e- BC
algorithm Pros Cons contracts governance platforms
SBFT Good security Not for public Yes Better than proof of methods Chain
Signature validation blockchain
dBFT Scalable Conflictions in the Yes Better than proof of methods NEO
Fast chain
FBFT Selection of Needs large Yes Better than proof of methods. Stellar,
validators number of Can be used in public Ripple
Decentralization transactions mode.
Can be used in public
blockchains
Tolerates upto 21%
DAG Low-cost network Implementation In process Highly suitable IOTA
Scalability gaps
Not suited for
smart contracts
(tangle)
Blocklattice smart
contracts (Vite)
DAG, directed acyclic graph; dBFT, delegated Byzantine fault tolerance; DPoS, delegated proof of stake; FBFT, federated Byzantine
fault tolerance; lPoS, leased proof of stake; PoA, proof of authority; PoBi, proof of believability; PoC, proof of capacity; PoET, proof of
elapsed time; PoI, proof of importance; PoS, proof of stake; PoW, proof of work; PoWeight, proof of weight; SBFT, simplified Byzan-
tine fault tolerance.

mechanisms. DAG-based approaches can also be tried. Smart
contracts using lattice structures as in Vite are highly suitable.
Such DAG-based DLT can be used in consortium mode also.
The possible attacks on BCs can be studied in the following
section. The countermeasures for overcoming these attacks will
be discussed.

4. Attacks on blockchain

The immutable nature of BC necessitates security audits and
testing before deployment. The major categories of attacks on a
BC include the following [19,20,22]:
(a) BC structure vulnerabilities: These attacks result in forks by
changing the linear structure of the BC. Changes in technol-
ogy and implementation such as network protocols and
data structures of an existing BC result in forking of the linear