Melonport, which recently completed one of the fastest crowdsales in history, is building the open source, blockchain based Melon protocol for digital asset management. Smart contract specialists Oraclize and price data gurus CryptoCompare worked together to create the very first Melon protocol price feeds which push market data directly to the blockchain. The smart contracts are now live on the Kovan Ethereum testnet.

Prices are updated every five minutes and to get full transparency, the average price for each asset is securely computed on-chain. Authenticity proofs attached to each transaction can be used to verify at any time that the data sent was authentic.

The contract supports any exchange providing the relevant data via Web APIs. In its current form, it is continuously fetching data from Bitfinex, Kraken, TheRockTrading and Poloniex to provide on-chain references of the BTC, EUR and REP exchange rates against ETH.

Using CryptoCompare Web APIs through Oraclize provides the benefit of having the data aggregated over all the trading exchanges. It would be a lot more expensive and harder to keep up to date if you had to aggregate the data on-chain; it also includes price information for more pairs and is easily extendable to fetch a lot more information if needed, said a posting on github.

George Hallam, head of business development at Melonport, said: "We're very grateful for the work put in by the Oraclize and CryptoCompare developer teams on these Melon price feed modules. Melonport is working very hard to build a healthy and vibrant developer ecosystem – each new module added will provide future Melon fund managers with a great deal of value."

"Because of Ethereum's permissionless nature, it's very easy for one project running on the platform to integrate with others like we're seeing here with Melonport, Oraclize and CryptoCompare. This creates a distinct sense of synergy between what would otherwise be disparate projects. We all benefit from each other's success.

Charles Hayter, CEO, CryptoCompare, said: "Oraclize are an enabler and have pushed CryptoCompare data to Melonport which communicates via oracles. The expertise of Oraclize in smart contracts means they have built it but also proved that the data hasn't been tampered with in their onboarding to Meloport by using public private key cryptography (ECDSA)."

Hayter said the contract leverages the new Oraclize Native Proof, which enables us to sign the data provided through our Web APIs using the HTTP signatures specifications. The smart contract can then verify the signature over the data using the data source public key, which is stored in the contract. If the signature verifies, the data can be consumed and the prices are updated.