# Addressing ZSM Security Issues with Blockchain Technology
## 7 Assessment of Blockchain and DAG Platforms to Be Used for the ZSM-Solution Implementation
### Candidate Blockchain and DAG Solutions for Our Approach
#### 7.1.5 Hedera Hashgraph  
Another DAG-based solution is presented by Hedera, named Hedera Hashgraph, which uses a distributed network, cryptographic tools and timestamps to store data in the form of transactions. This platform is considered a public permitted network, although it is currently governed by the Hedera Council which deploys and supports the network nodes. In the future, anyone will be able to host and operate a Hedera Hashgraph node.  
The consensus mechanism used in this DLT is called Hashgraph and is based on the gossip protocol [45]. Every node that transacts with another one sends information regarding the current state of the network which is based on information previously received by other nodes. As a result, the information regarding the current state spreads like gossip among the nodes of the network. Therefore, every node in the network contributes to the consensus process and every node is aware of the current state. Hashgraph achieves a high-throughput with 10,000+ transactions per second today and low-latency finality in seconds from its innovative gossip about gossip protocol and virtual voting. Once consensus is reached, the transaction is immutable and available on the public ledger for everyone to transparently see. It should be mentioned that the nodes store only the latest state of the network in their ledger, which automatically increases the scalability of the network.  
Additionally, Hedera Hashgraph offers a set of so-called Hedera Services that allow users to perform various tasks such as the creation of SCs and tokens. The Smart Contract service of Hedera allows the creation of contracts using the Solidity language similar to Ethereum-based networks, while Hedera promises fast SC execution with lower cost than blockchain alternatives. Moreover, tokens are supported by the Hedera Token service which allows the configuration and management of native fungible and non-fungible tokens. Having in mind our use case, an NP could receive a payment in the form of token for lending its resources to another NP. In addition, NFTs could be used as a reputation badge to highlight the reliability of an NP in our scenario. The support of SCs and tokens widens the application area of Hedera Hashgraph which can be used in various use cases.  
Nevertheless, an additional factor that adds extra flexibility to this platform is its ability to cooperate with oracle mechanisms. Chainlink and Hedera Hashgraph announced in 2019 their collaboration to integrate Chainlink's decentralized oracle solution with Hedera's network. Chainlink is a well-known oracle mechanism that allows smart contracts to securely access and retrieve off-chain information when needed. It uses a similar model to a blockchain, as it implements a decentralized network of independent entities, called oracles, that collectively retrieve data from multiple sources, aggregate it, and deliver a validated single data point to the smart contract to trigger its execution, removing any centralized point of failure [51].