# Next-Generation Payment System for Device-to-Device Content and Processing Sharing
## 2 Background  
Cryptocurrency and distributed ledger technologies have been attracting the attention of both research and business communities since their inception. The advent of distributed ledgers enabled enterprises and supply chains with the opportunity to delegate trust to a third party, which is a single source of truth, in a decentralised manner. As an abstraction, we may consider a ledger as a collection of data items that are replicated and distributed over different locations. These data structures do not require any central administration. Instead, consensus systems, such as proof of work, proof of stake, or virtual voting, are employed to ensure that all replicas are exactly alike. A peer-to-peer network is used as the underlying infrastructure for accessing data. The internal organization of the data may not be necessarily the same in all implementations. The enabler for distributed ledgers is the blockchain concept [7; 8] and there are many specifications for blockchain such as Hyperledger [9; 10], an open source project supported by Linux foundation, and the Hedera project [11], which places more emphasis on the efficiency of processing data. These mainly differ in their consensus algorithms, security mechanisms, and transaction speed. The Hedera project is especially promising in that it offers several orders of magnitude more transactions per second compared to other blockchain systems due to the difference in the gossip algorithm and its unique chainless distributed ledger called hashgraph, which makes Hedera a good candidate for micro-transactions that are needed between the users in the proposed framework. The idea for cryptographic electronic money was conceived in the early 1980s [12; 13], and early implementations appeared in the 1990s. Bitcoin [14], the first decentralized cryptocurrency, went online in 2009 and has made a huge impact since then. The list of use cases and potential applications for cryptocurrencies is ever-growing, and it has gained acceleration due to the imminent migration to 5G cellular communications. In this context, cryptocurrency can be seen as an enabler for smart home and smart city applications and Internet of Things (IoT)-based systems as well as enabling a payment scheme for 5G infrastructure coverage and use. Coupled with cryptocurrency, distributed ledger technologies has become powerful tools and platforms. Among its potential applications, one can list the following:  
* Smart contracts, where financial statements can be exchanged securely and truthfully, and the obligations of the contracting parties are verifed automatically [15; 16];
* Smart instruments that connect to the Internet and provide you more information about their applications and the surroundings [17]. These kinds of applications can also be extended to build communication infrastructure for different technologies (IoT, 5G, etc. );
* Supply chain transformation with blockchain integration [18];* Healthcare networking, where only authorized entities are provided access to personal records that are secured with blockchain [19];
* Artistic and intellectual property rights as well as digital rights management through blockchain [17];
* E-voting [20];
* Identity management by allowing only the necessary parts of personal information to be viewed by the requesting people, encryption of one's credentials, and record keeping for documents such as birth, marriage, and death certificates [21]. Cryptocurrencies and distributed ledger technologies have observed an eruption in popularity since the release of Bitcoin whitepaper [14]. Despite being the most prominent cryptocurrency, Bitcoin has a number of issues. Its mining process involves presenting a proof-of-work (PoW) in a new block, which includes finding a nonce value for the last block of the public ledger. This is a very energy-consuming process, requiring 204.5 KWh per transaction on average, which amounts to 204.5 TWh yearly consumption [22].