Page 212 - Big Data Analytics for Intelligent Healthcare Management

8.2 HEALTHCARE BIG DATA AND BLOCKCHAIN OVERVIEW 205

Table 8.1 Blockchain Consensus Algorithm Comparison
PoW PoS PoET PBFT DPOS Ripple Tendermint
Node Open Both Both Permission Open Open Permission
management
Transmission Low High Medium High High High Medium
rate
Energy High Medium Low Medium Low Low
consumption
Storage High High High High Medium Medium Medium
consumption
Scalability High High High Low Low Low Low
Finality Probabilistic Probabilistic Probabilistic Immediate Probabilistic Immediate Probabilistic
process
Transaction High High Medium Low Medium Low Low
cost
Adversary 25% <51% Stake Unknown <33% <51% <20% <33.3%
tolerated Computing Voting Faulty Faulty Voting
power power power replicas nodes power
in UNL

blockchain by utilizing the original characteristics of this technology such as: finance, healthcare, op-
erations management, IoT, basic science, intellectual property rights, automobile sharing, energy con-
servation, government, retail sector, human resources management [35–39]. According to Global
Fintech Report by PwC, 55% of respondents (companies with more than 500 employees) were plan-
ning to adopt it as part of a production system or process by 2018, and 77% by 2020 [40]. The com-
ponents of blockchain technology are defined below:
A block: this stores particular transaction information. In other words, we can define a block as a
permanent and immutable record. With a similar concept to an ordinary ledger, a block indicates a
current transaction or decision that will eventually indicate a new block as soon as a new transaction
occurs. Header, transaction counter, and transaction data are the three main parts of a block [41].
Header: Headers of blockchain content follow a list of information in separate subsections. Block
version represents the current block version number, which decides the regulations that this block fol-
lows. The parent block hash stores the previous block hash, which points to the previous block. The
Merkle tree root hash is a procedure of keeping blockchain information after a double SHA-256 hash-
ing. A tree element with double hashing was used by NISTIR [42], as shown in Fig. 8.7. The field time
stamp records the approval time of this particular block. Mining difficulty or block creation difficulty is
the target threshold. The last field variance is called nonce (one-time use), used only once. This intro-
duction of nonce changes the hash output of the block contents.
Transaction counter: This counts the total number of successfully completed transactions. It ex-
presses the serial number of the currently used block.
Transaction data: Depending on the usability, the purpose of this field varies. It can be used for
bitcoin transactions, contract records, healthcare info, and business data etc. For example, in the case of
healthcare, it stores clinical and medical information related to patients.