# Trusted Electronic Contract for Enabling Peer-to-Peer HPC Resource Sharing
## 2 Literature Review
In addition, creating the system can offer a number of managerial benefits to HPC providers, such as the ability to audit and trace the sources of anomaly actions, and the capability of making use of statistical data on resource usage and trends for making a rational decision for future resource supply investment or purchasing high-demand software licenses to attract users. Currently, however, studies on creating such a system in the HPC domain are still limited in number. Integrating blockchain with HPC aims to solve trust issues between public users and HPC resource providers by automating the process of digital agreement creation and regulating the actions with no central authorities required. Introduced by [PERSON], a practical peer-to-peer model of the electronic cash system emerged [11]. With the decentralized computation and management in blockchain technology, data security and transparency in business activities can be enhanced [12]. Transactions submitted to the network will be collaboratively validated against a _smart contract_, which is installed on all nodes. Only agreed actions will be propagated to the network, allowing all participantsto apply the changes to their local records. Regardless of states being replicated and locally maintained by individuals, consistency in network states can still be preserved through cryptographic mechanisms and efficient data structures (i.e., Merkle tree [13]) that allow the data validation process to be carried out with small time complexity. Instead of relying on a central authority to manage states, blockchain uses decentralized consensus algorithms to define how agreement in the network is reached. Examples of the algorithms are Proof of Work (PoW) [14], Proof of Stake (PoS) [15], and Practical Byzantine Fault Tolerance (PBFT) [16]. These benefits of blockchain expedite the development of various e-government services in which trusted data sharing among legitimate stakeholders is the primary concern. Examples of blockchain-based projects that have been implemented at a national scale are e-Transcript [17] (education), DLT scipless bond [18] and Letter of Guarantee on Blockchain [19] (finance), e-Referral system [20] (health care), National Energy Trading Platform [21] (energy), TradeLens [22] (logistic & supply chain). Nevertheless, introducing blockchain to HPC is more challenging compared to integrating it with application software. The solution design must present an approach for enabling communication between the application layer and OS layer. In contrast to HPC, blockchain's processing is asynchronous and slow in speed. To make sure data exchange between these two technologies is correct and remains synchronized, there must exist an auxiliary module for enabling system interoperability by bridging communication differences and handling unexpected error. As a result, the use of blockchain in HPC systems is still limited in the number of applications. Previous studies have emphasized presenting fault-toleration schemes to promote resiliency in Message Passing Interface (MPI) by proposing a blockchain consensus protocol that is optimized for HPC compatibility [23; 24]. To enable data consistency across shared storages in HPC systems, a study also focused on using blockchain technology for states synchronization [23]. With the ability of blockchain in preserving ownership [25], the technology was applied to improve data provenance in the HPC system by validating the source of data generated before being stored in a high-speed parallel file storage system [26]. The arrival of the data-driven era has expedited the generation of a large volume of sparse data. As a result, demand for intensive computing power is growing. On the contrary, people start to pay attention to the security and ownership control of their data. Trust, therefore, becomes a key requirement in designing large-scaled data computing [27].