Think of a blockchain oracle as a mediator between the crypto and non-crypto worlds. Its goal is to send relevant data between a smart contract's blockchain and an off-chain source.
Some technicians compare blockchain oracles with middleware or an application programming interface (API) for the Web3 space. These computerized systems transfer information from non-Web3 data feeds onto a blockchain.
Blockchains wouldn't have a way of "talking" to the outside world without oracles. On their own, blockchains like Ethereum (ETH) are closed systems that only manage on-chain activity. Oracles help bridge the gap between on-chain and off-chain data.
“On-chain” simply means the data and computation that occurs on a native blockchain. For example, the transaction history on the Bitcoin blockchain is “on-chain data.” Anything that’s “off-chain” refers to data stored off of a blockchain network. For instance, data in a centralized cloud server like Microsoft’s Azure will qualify as off-chain data. The prices of stocks on the NASDAQ is another good example of off-chain data.
Developers need oracle systems to help bring off-chain information into their dApps (decentralized applications).
So what's the point of using blockchain oracles? Why would a crypto project want off-chain data feeds? Since oracles can link crypto with the external world, they open up countless use cases for blockchain technology. With oracles, it's possible to use automated smart contracts to handle many real-world transactions.
Blockchain oracles can also enable trustless transfers of real-world assets like property. People can set the parameters for a smart contract before transferring ownership of these assets over the blockchain. The oracle will feed in the required legal documents until the smart contract's conditions are met. Once the smart contract registers all this external data, it can automatically transfer a tokenized ownership deed to the homebuyer.
Although blockchain oracles are most often used for price feeds on DEXs (decentralized exchanges), they have many exciting applications that developers are only beginning to explore.
An oracle gathers data depending on what information a developer wants to input. These data feeds can come from software or hardware sources. If an oracle solely tracks information on the web, it may pull data from APIs on centralized crypto exchanges. Hardware oracles, however, can collect data from physical devices like a thermostat or a QR scanner.
The unique feature of decentralized crypto oracles is that they rely on multiple node operators to query, validate, and transfer data. The decentralized structure of these crypto oracles helps ensure the off-chain or on-chain data is valid. Since every data point has to pass through so many validators, it reduces the odds of mistakes.
This information is then relayed to the associated smart contract in a coded message. If the smart contract successfully reads this information, it should verify on the blockchain.
All blockchain oracles share a similar goal: Securely bridge information from on-chain and off-chain sources. However, not all oracles go about this task in the same way. Below are a few key ways people distinguish blockchain oracle networks:
The crypto community’s major concern with oracles is the risk of centralization. Centralized blockchain oracles have a hierarchical structure with easily identifiable leadership and a clear concentration of data. If smart contracts were to rely on these centralized oracles, they’d invalidate the decentralization of a blockchain's architecture.
Although a blockchain like Ethereum is decentralized, introducing a centralized oracle means people need to rely on the oracle network's trustworthiness. Even if a centralized oracle has high standards for transparency, there's a greater chance of data corruption. It only takes one successful hack on a centralized oracle provider to destroy the validity of a blockchain's smart contracts.
Most blockchains favor decentralized oracle services to mitigate this threat. Projects like Chainlink use consensus mechanisms, token incentives, and multiple nodes to ensure the data isn't flowing from just one source to another. Blockchain experts are hopeful the further development of decentralized oracles can effectively solve the oracle problem.
There's no limit to the potential use cases for blockchain oracles. Web3 developers are devising novel ways to bring decentralization into real-world finances, investments, and transactions. Although the possibilities of blockchain oracles are endless, here's a sampling of the current uses of this technology:
Oracles will play a crucial role in the evolution of blockchain technology. Their off-chain data can help countless real-world industries explore the potential benefits of smart contracts. As Web3 developers continue to tinker with this technology, it’ll be exciting to see how oracles inspire future DeFi applications.
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