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.
Viacoin is a Script-based cryptocurrency derived from Bitcoin. Similar to Bitcoin and other cryptocurrencies, Viacoin is also an open-source project. Viacoin aims to be the cryptocurrency of future, by integrating many innovative key technologies such as SegWit, APoW, Lightning Network, Dark Gravity Wave, and more. Viacoin claims to allow 25 times faster transactions than Bitcoin. It can be merged mined with the other Script cryptocurrencies like Litecoin, This is done by using an Auxiliary Proof-of-Work (AuxPoW) algorithm. Every six months, Viacoin halves the block reward that is given to users for Viacoin mining, resulting in a low inflation rate of Viacoin. Check out CoinBureau for the complete review of Viacoin.