Smart contracts are on track to be the leading form of digital agreements which form the backend of key global industries. However, in order to maintain a contract’s overall reliability, the inputs and outputs to the contract also need to be secure. In this talk, we’ll define and examine what makes a secure oracle mechanism reliable enough to be used by smart contracts for external data delivery, access to web APIs and off-chain payments. We’ll review the security risks and failure scenarios to avoid when using oracles and share how developers should set up methods to maximize success. We’ll look at how a decentralized oracle network can make oracle mechanisms more secure. Finally, we will present an in-depth approach that applies additional layers of security through the use of Trusted Execution Environments and cutting edge approaches such as TownCrier.