Smart contracts on Ethereum are fully self contained and any information or access to off-chain data is restricted. Tellor solves this problem by creating a system where parties can request the value of an off-chain data point (e.g. ETH/USD) and miners compete to add this value to an on-chain data bank, accessible by all Ethereum smart contracts. Inputs to a data series are secured by a network of staked miners. The main Tellor smart contract creates a time series of each requested data series and aims to become the standard source of high value data for decentralized applications. This oracle, “Tellor”, utilizes similar incentive mechanisms to other cryptocurrency systems through the issuance of Tellor’s token, Tributes, that are used to request a particular data series from miners.
Hedera is a decentralized public network where developers can build secure, fair applications with near real-time consensus. The platform is owned and governed by a council of global innovators including Avery Dennison, Boeing, Deutsche Telekom, DLA Piper, FIS (WorldPay), Google, IBM, LG Electronics, Magalu, Nomura, Swirlds, Tata Communications, University College London (UCL), Wipro, and Zain Group. The Hedera Consensus Service (HCS) acts as a trust layer for any application or permissioned network and allows for the creation of an immutable and verifiable log of messages. Application messages are submitted to the Hedera network for consensus, given a trusted timestamp, and fairly ordered. Use HCS to track assets across a supply chain, create auditable logs of events in an advertising platform, or even use it as a decentralized ordering service.