version 1.0 (pdf version)

  1. Blockchain paradigm

History : Over the past few years, an important innovation colloquially known as the “Blockchain” has emerged as a potentially disruptive technology. The core of the innovation is built around the concept of a distributed cryptographic database. The database, also referred to as the ledger, is maintained by a network of computers. The ledger makes it possible for the entire network to create, evolve and keep track of an immutable record of transactions. The most successful blockchain application thus far has been Satoshi Nakamoto’ s cryptocurrency known as Bitcoin, which he outlined in his seminal paper, “Bitcoin: A Peer-to-Peer Electronic Cash System” in 2008. This powerful technology has so far been implicated in the numerous cryptocurrencies that exist online. Financial institutions are only beginning to understand the potential applications of blockchain in conventionally regulated industries.

Understanding the Blockchain : At a fundamental level the blockchain is a data structure that cryptographically links blocks of transactions or any potential transfers of value. As a paradigm, the blockchain allows for true privacy to exist between those involved in a transaction. This characteristic of the blockchain that makes its most significant implementation in the financial industry. Its structure allows for automation, immutability, and decentralization. These characteristics were carefully chosen by Nakamoto in order to create a digital mechanism of trust. For the financial world this would result in a more limited reliance on third party trust mechanisms enabling a direct contractual interface between two parties involved in any transfer of value. This technology has the power make such exchanges safer, faster, and costeffective. Ownership of value stored in the blockchain is established through asymmetrical cryptography. Digital keys, wallet addresses, and digital signatures are all created cryptographically to ensure total privacy in transmission of transactional data. Every transaction on the blockchain needs to be 'signed' using digital keys. Whoever owns these keys, owns access to the value stored in the wallet. All keys generated by the wallet software come in pairs; a private key, which is kept secret and a public key. The public key is akin to a bank account number and the private key is like the secret pin used to control the account. The idea behind digital signatures is that private and public key pair shares a mathematical relationship such that a message (transaction) signed by a private key can be verified by a public key without revealing the private key.

Public Blockchain : The Bitcoin's blockchain network is structured as a peer-to-peer network architecture. In this network implementation, all nodes are equal or symmetric. There is no server, no centralized service, and no hierarchy in the Bitcoin's network. Blockchain implementations for the financial industry however, cannot allow for such an open and symmetric network structure. Bitcoin enthusiasts advocate, therefore, that the blockchain and Bitcoin are fundamentally linked. This is a short sighted view taking into consideration that the Bitcoin technology stack exists to solve the problem of an unregulated digital currency. The same stack can be evolved to solve similar transfers of value over an asymmetric network. The XDC Protocol: Technical Whitepaper by Xinfin Organization. September 2017. All rights reserved. V1.0 4 The development of the Ethereum blockchain was a major milestone in the blockchain ecosystem. The focus shifted onto system state and virtual machines that could run smart contracts across the network. With the availability of Turing complete smart contracts, the limited functionality of the Bitcoin scripting language was overcome and a number of different applications became possible.

Private Blockchain : Private blockchains came into prominence with the Hyperledger Project that saw participation from IBM and Intel in 2016. Another major private blockchain developed by R3 called Corda also raised significant amounts of money. Since then, R3 has also joined the Hyperledger Project. Fully private blockchains make the case that centralized and trusted implementation of the core data structure of the blockchain along with significant changes to the consensus mechanism are meaningful value propositions for enterprise applications.

Hybrid Blockchain : Hybrid blockchains are fairly unexplored and only few implementations exist; even in development. Quorum developed by JP Morgan is designed to be the hybrid blockchain in a fully permissioned environment. Truly Hybrid blockchain must necessarily be able to connect public blockchain with a private blockchain implementation running in a fully permissioned environment. The XDC hybrid blockchain aims to be exactly that, leveraging the power of both the public and private blockchain paradigms.