As mentioned earlier, Zarela’s smart contract has been developed on the Ethereum blockchain platform and it is open-source and available to public. In Zarela, users are not required to complete registration and authentication. Technically speaking, any user’s interconnection to the Zarela would be through the written smart contract. Therefore, users will be known by their address of wallet that is generated by the Ethereum network. This is a feature of the blockchain that details of the user’s communication with the Ethereum blockchain (including details of any exchanged bio-signal file) would be encrypted and remain unknown to the Zarela’s platform and to the Ethereum network itself. The only prerequisite for Zarela’s users is to have an Ethereum wallet such as Metamask and a sufficient amount of Ethereum for their transaction fees.