To facilitate the self-execution, a smart contract needs access to sources of event information through which the execution of its terms and conditions is assessed. "In the interest rate swap example, the distributed ledger must have access to assets of the parties' in order to fulfil the parties' payment obligations, and it must have access to a provider of interest rate information."Jenny Cieplak and Simon Leefatt, 'Smart contracts: A smart way to automate performance' (2017) 1 Geo L Tech Rev 417. The solutions to the issue of access to assets vary and may be solved through locking and release of assets in smart contract as it is performed through use of cryptocurrency Ether on Ethereum blockchain or by introducing new mechanism of access to assets like 'cash states' proposed by Corda distributed ledger.https://docs.corda.net/_static/corda-technical-whitepaper.pdf The solution to the issue of access to information may require use of so-called 'Oracles' - an external party (or a machine) providing the judgement to determine whether or not respective conditions under the agreement have been met. "Turning again to the interest rate swap example, an oracle could be used to provide interest rate information on a payment calculation date. The oracle's digital signature would be retained on the distributed ledger so that parties could review the payment process and confirm that payments were made correctly."
