Oracle -
Blockchains and smart contracts cannot access data from outside of their network. In
order to know what to do, a smart contract often needs access to in- formation from the
outside world that is relevant to the contractual agreement, in the form of electronic
data, also referred to as oracles. These oracles are services that send and verify real
world occurrences and submit this information to smart contracts, triggering state
changes on the blockchain.
Oracles feed the smart contract with external information that can trigger predefined
actions of the smart contract. This external data stems either from so ware (Big-data
application) or hardware (Internet-of-Things). Such a condition could be any data, like
weather temperature, successful payment, or price fluctuations. However, it is
important to note that a smart contract does not wait for the data from an outside
source to ow into the system. The contract has to be invoked, which means that one
has to spend network resources for calling data from the outside world. This induces
network transaction costs. In the case of Ethereum, this would be “gas.”
There are different types of oracles:
Software Oracles
handle information data that originates from online sources, like temperature, prices
of commodities and goods, flight or train delays, etc. The so ware oracle extracts the
needed information and pushes it into the smart contract.
Hardware Oracles
Some smart contracts need information directly from the physical world, for example,
a car crossing a barrier where movement sensors must detect the vehicle and send
the data to a smart contract, or RFID sensors in the supply chain industry.
Inbound Oracles
provide data from the external world.
Outbound Oracles
provide smart contracts with the ability to send data to the outside world. An example
would be a smart lock in the physical world, which receives payment on its
blockchain address and needs to unlock automatically.
Consensus-based Oracles
get their data from human consensus and prediction markets like Augur and Gnosis.
Using only one source of information could be risky and unreliable. To avoid market
manipulation, prediction markets implement a rating system for oracles. For further
security, a combination of different oracles may be used, where, for example, three
out of ve oracles could determine the outcome of an event.
The main challenge with oracles is that people need to trust these outside sources of
information, whether they come from a website or a sensor. Since oracles are third-
party services that are not part of the blockchain consensus mechanism, they are not
subject to the underlying security mechanisms that this public infrastructure provides.
One could replicate “man-in-the-middle attacks” standing between contracts and
oracles.
The robustness assurance of this “second layer” is of utmost importance. Different
trusted computing techniques can be used as a way of solving these issues. However,
this topic will need more attention, as secure oracles are a bottleneck for smart
contract security. If oracle security is not adequately provided, it will be a show stopper
for widespread smart contract implementation.
Oracle Coins:
1. Chainlink (LINK):
Chainlink’s decentralized oracle network provides the same security guarantees as
smart contracts themselves. By allowing multiple Chainlinks to evaluate the same data
before it becomes a trigger, we eliminate any one point of failure and maintain the
overall value of a smart contract that is highly secure, reliable, and trustworthy.
1. Band Protocol (BAND):
Band Protocol offers a decentralized data oracle by making data readily available to be
queried on-chain, using delegated proof of stake (“dPoS”) to ensure data integrity. It
aims to be the go-to data infrastructure layer for Web 3.0 applications by providing
decentralized, curated off-chain data to smart contracts through oracles managed by
its dPoS consensus mechanism.
1. Augur (REP):
Augur is a decentralized oracle and peer to peer protocol for prediction markets.
Reputation (REP) is a cryptocurrency, used by reporters during market dispute phases
of Augur. REP holders must perform work, in the form of staking their REP on correct
outcomes, to receive a portion of the market’s settlement fees.
1. API3:
API3 is the native token of the API3 project, that grants its holders full governance
rights in the API3 DAO and acts as collateral in the data feed insurance pool. Staking
API3 into the data feed insurance pool earns the staker a governable share of data
feed revenues, as well as inflationary staking rewards.
API3 is a DAO-governed project for the creation of dAPIs — fully decentralized and
blockchain-native APIs — which will be set up, managed, insured, and monetized at
scale by the API3 DAO. With dAPIs, API3 aims for the concept of an API to take the
next evolutionary step to meet the inevitably strict decentralization requirements of
Web 3.0 without employing third-party intermediaries.
API3 provides smart contract developers with oracle data feeds that are:
Free of middlemen
Source-transparent
Truly decentralized
Quantifiably secure
1. Tellor (TRB):
Tellor is a decentralized Oracle for bringing high value off-chain data onto Ethereum.
The system utilizes a network of staked miners that compete to solve a PoW challenge
to submit the official value for requested data. Tokens are mined with every successful
Tellor data point and the company takes a 10% dev share to support the development
of the ecosystem.
1. DIA:
DIA (Decentralised Information Asset) claims to provide financial institutions with an
immutable and verified single source of financial market data for any market and asset
type. DIA also claims to be an open-source, data and oracle platform for the DeFi
ecosystem. It is further claimed that DIA leverages crypto economic incentives to drive
supply, share and use transparent, crowd-verified price data and oracles on financial
and digital assets. This token is claimed to be a governance token.
1. Umbrella Network:
Umbrella Network aims to create a scalable, cost-efficient, and community owned
oracle for the DeFi and blockchain community.
1. HAPI:
HAPI is an on-chain cybersecurity protocol with trustless oracles preventing hacker
attacks.
It is designed to provide:
real-time data with stolen funds and compromised wallets instantly to the end-user
real-time data with smart contract security audits
decentralization of data providers (elected by DAO)
easy implementation (less than one dev day)
1. Nest Protocol (NEST):
The NEST Protocol is a decentralized network of price predicators developed based on
the Ethernet Square Network.
NEST provides a creative solutions, including collateral asset quotation, arbitrage
verification, price chain, beta coefficients, and other modules to form a complete
NEST-Protocol.
1. Oraichain Token (ORAI):
Oraichain is a data oracle platform that aggregates and connects Artificial Intelligence
APIs to smart contracts and regular applications.
The blockchain network is built based on Cosmos SDK along with Terdemint’s
Byzantine Fault Tolerance consensus that helps speed up transactions’ confirmation
time.
When ORAI mainnet is officially launched, the ORAI token is required to secure and
power the decentralized oracle network of validators. The native ORAI token is used
for:
Staking for validators: all validators are required to stake ORAI in order to be
selected to create a block or fulfill data requests.
Transaction fee: the ORAI token is required in order to run an AI request sent to the
Oraichain network.
Participation in Oraichain Governance: the Oraichain network is organized in the
DAO manner, all protocol upgrades and parameter changes must be voted by token
holders.