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Blockchain Technology

On the contrary, the Tangle employs the DAG data structure to append validated

blocks to the Tangle. A transaction is attached to two previous blocks. Multiple

blocks could be included to the Tangle simultaneously, as shown in Figure 16.4. The

numerous blocks attached simultaneously eliminate the bottleneck in blockchain

architecture, as shown in Figures 16.2 and 16.3.

16.2.2  Consensus Protocol

In blockchain, miners and users constitute the network. The miners validate the

transactions for integrity using the PoW protocol, while the users initiate transac­

tions. The mining incurs enormous computing power. The users provide an incentive

to the miners to execute this function, thereby imposing a high network fee on the

blockchain network. A valid transaction is referred to as a block. Blockchain adopts

the PoW to validate and secure the network from attackers.

The IOTA Tangle, on the other hand, does not require miners to validate trans­

actions. It preferably employs “coordinators” temporarily for transaction validation

and confirmation. The PoW is used just to discourage spam transactions.

Note that the IOTA Foundation declares that the use of “coordinators” is tempo­

rary and should be replaced for better performance (Robert Shorten, Bill Buchanan,

Serguei Popov, n.d.).

16.2.3  IoT Architecture and Connectivity

The development of ever-present computing infrastructure in which a vast array of

heterogeneous digital devices that are uniquely identified and interconnected for

interacting with one another in real time, collecting and transmitting data, requires

FIGURE 16.3  Blockchain data structure.