ASTRI 2016 (†806)ASTRI. "Whitepaper On Distributed Ledger Technology" (Hong Kong Monetary Authority, 2016).
- Ethereum (p.35): Ethereum, launched in July 2015, is an unpermissioned DLT platform for decentralised applications. Like other unpermissioned blockchain platforms, the Ethereum blockchain is maintained by all connected nodes in the public network. Transaction verification and block creation is performed by validating nodes, also known as miners. Newly created blocks are then propagated to the network. · Ethereum serves as a flexible platform for anyone wishing to program blockchain applications on the Ethereum Virtual Machine (EVM).8 EVM can be thought of as a decentralised machine containinga number of different objects known as “accounts”, which are capable of executing code. There are two types of accounts: Externally Owned Accounts (EOAs) and Contract Accounts. EOAs are accessed externally with private key verification, and Contract Accounts are governed by their internal codes. Smart contracts are computer codes added to transactions by users and sent to the ledger for deployment. Smart contract execution may be triggered by additional user-sent transactions. Sending a transaction to the account in EVM requires a small fee payment known as “gas”. The fee is a reward to the miners to compensate them for their costs in hardware and electricity in performing transaction validation and block creation. · The reward is paid in the Ethereum native cryptocurrency, ‘Ether’. It can be traded or used as a medium of payment on cryptocurrency exchanges, such as the Coinbase wallet system. Ether has been developed as a vehicle to facilitate the operation of peer-to-peer smart contracts. (†2058)
- hash value (p.23): A DLT ledger contains a large number of blocks and a large amount of transaction data. Once the blocks and the transaction data have been stored in a ledger, these blocks and data are immutable, i.e. cannot be altered. At the macro level, the consensus process among validating nodes ensures that no malicious validating nodes can inject falsified transactions into a DLT network. At the micro level, hash technology is applied to detect any alteration made to the original data. This is a mathematical unidirectional function that summarises a piece of data, regardless of its size, as a piece of unique fixed-size short data called its “hash value”. Any alteration to the data causes its hash value to change also. Hence, instead of having to inspect every piece of information in the lengthy data record in order to detect data alterations, one only needs to run the hash function on the data record to obtain a hash value. If the hash value has changed, then one can conclude that the data record has been altered. · The strength of the hash function is that it is close to impossible for anyone to determine a hash value in advance, and then to create a data record that will in turn produce the pre-determined hash value. A minor change in the original data record will result in major changes in the hash value. There are different hash algorithms in the technology world. A common example is SHA256, which reduces a data string of any size to a 256-bit number... (†2059)