The prolific rise in the value of cryptocurrencies, such as Bitcoin and Ethereum, has led to increasing awareness of their underlying technology - blockchains. Blockchain is a peer-to-peer distributed public ledger of transactions, or database, which includes public-key cryptography. That means the technology offers properties desirable for trusted collaboration, such as confidentiality, integrity, authenticity and validity without relying upon a central authority. Some variants of blockchain technology also include smart contracts, which is the ability of blockchains to execute autonomous scripts capable of representing verifiable application logic.

Despite that increased awareness of what blockchains represent, there are very few thorough tutorials on how to develop distributed applications (dApps) for blockchains. Therefore, the motivation for this talk is to attempt to demystify blockchain-based development of a smart-contract based dApp for beginners.

To aid that demystification process, we will investigate a live example of a dApp Provenator, a web app developed to counter the rise of fake news, whose development was the result of an academic paper called Fake News - a Technological Approach to Proving Provenance Using Blockchains.

Provenator comprises two parts: a React-based Javascript frontend, and an Ethereum-based smart contract blockchain backend. During the session, we will investigate both of those parts, and, in particular, focus on how they are glued together, including instantiating the Ethereum API from within React, interfacing with the smart-contracts, and then sending and receiving asynchronous transactions to those contracts. Once we have done that, we will deploy the constituent parts to their respective distributed infrastructures - for the React front end, that will be the InterPlanetary File System (IPFS), and for the smart contract backend, it will be the Ropsten test Ethereum network. Finally, we will load the dApp into a browser and see it in action.

You will need:

• Some basic coding knowledge in any language (some experience with JavaScript and React.js is preferable, although not necessary)

• a GitHub account (so you can fork Provenator).

• The following dependant packages installed: node, npm, geth, Ganache, Truffle, http-server and IPFS.

• The browser plugin MetaMask (which, once the dApp is running on the Ethereum test network Ropsten, will enable you to sign the transactions that the dApp creates).

• To pay for those transactions, you will need to acquire some test Ether via the Ropsten faucet. That relies on you having a social media account, such as Twitter or Facebook.

If there's time at the end of the 3 hour session, we will look at some ideas as to how to further develop Provenator. After all, the ultimate aim of the software is for it to become a full-blown dApp on the live Ethereum network. That way, it will be able to prove the provenance of digital assets, thus making it a tool able to counter the rise of fake news.

To guarantee a place, please register a ticket as soon as you can. If you have any questions about this event or would like to know more please drop us a line at Joe@wiredsussex.com.