H. Hard Fork
To respond the hacking of the DAO, Ethereum was
divided into Ethereum Classic and the new Ethereum. As a
hard fork from the original software, the new Ethereum can
protect against further malware attacks. Ethereum Classic has
tokens called ETC while the new Ethereum has tokens called
ETH. Both the new Ethereum
and Ethereum Classic have a
common ancestry prior to Block 1,920,000.
VII.
C
HALLENGES AND
R
ESEARCH
T
RENDS
There are some existing surveys which have presented the
future trends or scopes for Blockchain technology. Blockchain
testing, big data analytics, Blockchain applications,
smart
contract, stop the tendency to centralization, and artificial
intelligence are listed by the same research group in [3] [27].
Hybrid consensus mechanism, more efficient consensus, code
obfuscation, execution trusted
computing against privacy
leakage risks, application hardening, and an efficient data
cleanup & detection mechanism are presented in [29]. A
standard testing mechanism, big data analytics, smart contract
development and evaluation are proposed in [49]. Resolving
bug
of Blockchain technology, more use cases and
applications, and promoting the awareness of Blockchain
technology are described in [48]. Besides those
valid trends
and scopes, this paper would highlight the below challenges
and research trends.
A. Scalability
