# Easing DApp Interaction for Non-Blockchain Users from a Conceptual Modelling Approach
## 8 Conclusions and Future Work  
Blockchain supposes a new paradigm that not only has revolutionized the world digital economic system but also the foundations of distributed data management. Thus, beyond cryptocurrencies such as Bitcoin, blockchain provides us with the required tools to create smart contracts that will run in a distributed environment. Thanks to these smart contracts, we can develop blockchain distributed  
Figure 10: Elapsed time results (in seconds). applications, or DApp's. These are applications that will run in a distributed manner on the blockchain by obeying the rules codified on the smart contracts. The problem with a relatively new-fanged technology such as blockchain is that users need to be aware of many concepts before interacting with an application of this sort (e.g., addresses, private keys, wallets, gas, gas price, transactions, signatures, etc.). Therefore, it is very common that a user confronting a DApp for the first time fails, due to the pronounced learning curve required to interact with blockchains. To tackle this issue, which is related to RQ1 (Which is the correspondence between the typical app interaction elements and DApp ones?) we analyzed and related the elements of both DApps and Apps by using conceptual modeling. Hence, this analysis leads us to the identification of how a user would be able to interact with a blockchain through an App in an easy manner, thus not requiring any knowledge of blockchain concepts. After this analysis, we proposed the use of a middleware that will ease the interaction with a DApp by making users feel like they were using a typical web application, thus answering RQ2 (How can DApp interaction be improved for users without blockchain experience?). Indeed, instead of using wallets, public addresses, private keys, and signed transactions, they will interact by using concepts they are familiar with, namely emails, passwords, and web interfaces. In other words, this middleware will make users able to interact with a DApp without any blockchain knowledge. Therefore, our middleware consists of five approaches that will facilitate the interaction with a DApp: enabling login with email and passwords, sending transactions, decoupling users' credentials from blockchain data, tokens management and security concerns. To demonstrate how to put the middleware into practice, we presented a DApp that tracks employees' schedules by using an Ethereum-based permissioned blockchain. Hence, this DApp implements all the approaches of the proposed middleware, thus easing the user interaction without losing the security and reliability of blockchains. Finally, to answer RQ3 (Does the inclusion of typical app interaction features in a DApp improve its usability for users without blockchain experience?) an experiment was performed. With this aim, we enrolled 38 participants from three deferent software development companies with no experience with Blockchain. Then, they performed several tasks with two versions the DApp, one implementing the proposed middleware and the other one without it. We conclude that implementing the middleware widely improved the DApp usability. Despite the positive results obtained by this experiment, our work has several limitations. First, the experiment was conducted by using participants with no blockchain experience. Therefore, our results are not generalizable for blockchain advanced users who could consider our proposal not necessary. Therefore, further experimentation could be performed to broaden the usability of DApps featuring the proposed middleware. Second, our proposal is Ethereum-based, therefore, we cannot assure that it could be applicable to different blockchains. Because of this reason, additional middlewares are required to fulfill the needs of non-exert users to deal with other blockchains. Finally, the inclusion of Firebase in our proposal makes the DApps that implements this middleware not fully decentralized. Consequently, different alternatives need to be considered to foster the proposal's decentralization.