## 2 Related Work
In [14], the use of different smart contracts (including a payment token and an asset manager) in the media industry, combining blockchain, web technologies and user-generated multimedia content,allowing direct monetization for the content creator, is examined. A huge number of financial banking transactions take place every day. It is indicative that in July 2019 the Society for Worldwide Interbank Financial Telecommunication (SWIFT) recorded an average of approximately 32 million transactions per day [15; 16]. Blockchain can enable parties with no particular trust in each other to exchange digital data on a peer-to-peer basis with fewer or no third parties or intermediaries. In the recent report Scientific and Technical Research Report of European Commission on Blockchain [17], the need for Know Your Customer mechanisms is highlighted: \"the obligation of cryptocurrency exchanges and custodian wallet providers within the scope of EU regulation to implement mechanisms to counter money laundering and terrorist fundraising, such as 'know your customer' (KYC)\". Blockchain-based identity management and authentication frameworks have been proposed [18; 19] recognizing the potential of decentralizing the ownership of credentials and offering a universally available protocol for verifying one's record in an immutable chain of data. [PERSON] et al. [20] proposed an authorization and authentication proof-of-concept system for identity management based on a use case concerning Electronic Health Records, where an immutable and auditable history is desired for data concerning patients. [PERSON] et al. [21] presented a blockchain-based authentication and authorization framework to control access to the resources of an IoT device, while [PERSON] et al. [22] examine the integration of national identity with blockchain technology. It is evident that previously mentioned works involve value exchange through blockchain transactions and dedicated created smart contracts, making Know Your Customer processes necessary. In this direction, a system is presented that successfully blends smart contracts for exchanging value in the media industry in a decentralized manner, integrating a KYC process handling on-chain and off-chain data. Recent works have tried to tackle the problem of data management and KYC for blockchain applications. [PERSON] et al. [23] introduced a blockchain-based KYC proof-of-concept system and an orchestration tool for managing private blockchain environments over large-scale testbeds. In their work they highlight the need for additional research on security and privacy issues of blockchain applications. [PERSON] et al. [24] presented a demo of a system that allows automation and permissioned document sharing in order to simplify and reduce the work required by the KYC process, while [PERSON] and [PERSON] [25] conducted research on a digital copyright management system based on blockchain technology. They focused mostly on a PBFT consensus mechanism improved by Tendermint [26], replacing the original Ethereum POW, digital signatures and smart contracts to design user account management strategies, copyright review, and applications for the needs of digital rights management. In this work, the design and implementation of smart contracts for the KYC process on a decentralized approach are further explored. Blockchain is beginning to transform industries and there is an increasing interest in exploring its potential for various production use cases, especially for supporting multi-party processes where members do not necessarily trust each other. However, there are many challenges that remain to be addressed such as trade-offs between respecting privacy and supporting transparency. [PERSON] et al. [27] described the design of smart contracts for consent-driven and double-blind data sharing on the Hyperledger Fabric blockchain platform [28] into a KYC application, where the data are submitted, validated and kept within the ledger, supporting different consent rules and privacy levels. [PERSON] et al.