**4.1 Blockchain**

In 2008, the first technology was introduced, based on the concept of a decentralized network called blockchain. If in a centralized network, the security of a transaction is assumed by the central authority, then in this concept, security is determined by the interaction of its participants. The classic representative of the system is Bitcoin, based on this technology. Bitcoin is a chain of immutable blocks (**Figure 1**), the integrity of which is confirmed by the Proof-of-Work consensus protocol. To add a new block to the network, it is necessary to perform some "work," during which the block information is confirmed [19]. This protocol provides sufficient network security, but the structure in the form of series-connected blocks and the use of an expensive protocol for finding consensus do not allow unlimited scaling. In our

**Figure 1.** *Visualization of blockchain technology.*

**Figure 2.** *Visualization of Hashgraph technology.*

**Figure 3.** *Visualization of TraceChain technology.*

#### *Perspective Chapter: Prospects of Using Blockchain Technology in the Tourism Industry DOI: http://dx.doi.org/10.5772/intechopen.108526*

opinion, at the moment, blockchain technology has almost exhausted its potential and is in a state of alternative to the gold exchange system.

During further development, Blockchain technology was able to increase its throughput, for example, Ethereum, but this problem still remains relevant.

### **4.2 Hashgraph**

In 2017, the Hashgraph technology was released, the rights to the algorithms of which belong to Swirlds (HEDERA) [20]. The technology was supported by large companies that formed a platform called "Hedera Hashgraph Platform." The technology is currently patented, and the only authorized ledger is Hedera Hashgraph (**Figure 2**).

The Hashgraph technology does not use the blockchain in its structure; directed acyclic graph (DAG) was taken as the basis. The structure of the technology is the ledger in which no transaction is discarded. The interaction of network nodes is a constantly expanding tree [21] (**Figure 2**). Hashgraph technology uses other ways to achieve consensus between network participants when interacting, one of which is called "gossip about gossip." When sending information, a network participant randomly selects another participant to whom it transfers all the information it has accumulated in the form of a hash (Already encrypted data is transmitted, which contributes to confidentiality). This algorithm is repeated several times, resulting in a tree that has the general direction, which named Hashgraph [19]. The rate of dissemination increases exponentially until a consensus is reached.

The network structure and consensus technology allow Hashgraph to be fair, fast, compliant, efficient, inexpensive, timestamped, and resistant.

This project is supported by large companies such as LG, Google, IBM, and Ubisoft.

The HEDERA platform supports the following areas: enterprise, gaming, healthcare, and case studies.

## **4.3 TraceChain**

In 2017, TraceChain technology was developed. The technology is based on AI, which determines the structure of the network, and distributes nodes to ensure maximum speed [19]. Checking the correctness of transactions is extremely fast, as it is performed immediately on all devices at the same time. The outer radius of the network keeps connections with many clients, the middle one—the load from slow intercontinental connections, and the central parts of the network are responsible for the complete synchronization of lost transactions. This forms a new type of consensus called multi-PoS (**Figure 3**). The average transaction processing speed is up to 3 seconds [21].

This technology at this moment belongs to MetaHash AG (METAHASH) [22], which develops and promotes the product on the technology market. The transaction approval rate of more than 50,000 transactions per second is achieved by the optimal location of the nodes in the network. Like competitors, this technology has vulnerabilities, the main of which is the cybersecurity problem, which is being optimized by the developer company.

Distributed ledger technologies may become new growth points in the tourism industry (**Table 1**).


**Table 1.**

*Comparative analysis of the existing technologies of distributed ledger.*

The introduction of distributed ledger technologies in the tourism sector opens up new opportunities, which determines the importance of technology in this area [23]. Decentralization, fee reduction, smart platform applications, elimination of intermediaries, and security will allow tourism to move to the next level. The choice of a system for the transition depends on the starting conditions (financial resources, the required speed of transactions, etc.). For example, blockchain is reliable and low in cost, while limited in the speed of transactions, Hashgraph is expensive, while providing a high transaction speed, TraceChain is budgetary, and provides a high transaction speed, while the security of this option, at this moment, is inferior to competitors. Studies conducted by other research and development organizations [18, 24] have the same results.
