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Blockchain Technology
Conversely, IOTA implements the Markov Chain Monte Carlo (MCMC) and a tiny
PoW to verify and decide valid blocks (Kljajic, 2018). In this algorithm, every node
in the network must approve two previous transactions directly or indirectly to ensure
that the entire network achieves consensus (Foundation-IOTA, 2021). This method
involves little computing, storage, and network overhead, provides high throughput
and is highly scalable. An increase in transaction traffic proportionally speeds up the
network. As per IOTA Foundation, this node is temporary and referred to coordina
tors (Foundation-IOTA, 2021). This feature is most appropriate for IoT devices with
low resource constraints. IOTA application hardware are shown in Figure 16.9.
16.5.2 Data Structure
The data structure defines how data is systematically stored in the computer for
efficient use. In the context of DLT, the data structure is the method of appending
approved transactions to the network. Blockchain adds valid blocks using a sequen
tial hash graph (Zhixiong, 2020). Only one block is added at a time, as illustrated
in Figure 16.2. This method is not efficient and accounts for blockchain’s scalability
issues. For instance, statistics shows that the Bitcoin blockchain performs an average
of seven transactions per second (Kenney, 2019).
IOTA, on the contrary, implements the DAG data structure. It allows the addi
tion of multiple blocks simultaneously, thereby building the Tangle, as shown in
Figure 16.3. This method is highly scalable in comparison with the blockchain.
IOTA processes 250 transactions per second on average.
16.6 SUMMARY, CONCLUSION AND RECOMMENDATION
This chapter considers two out of several DLTs in the market: Blockchain and IOTA.
It briefly analyzed the architecture and application domains. The focus, however, is
FIGURE 16.9 Sample hardware supported for building IOTA applications. (From Espressif,
ESP Audio DevKits, Espressif Systems, 2021, www.espressif.com/en/products/devkits/esp-
audio-devkits)