# Enhancing Data Integrity in Blockchain Oracles Through Multi-Label Analysis
## 2 Key Concepts
### Current Knowledge Status  
Interoperability between blockchains has highlighted the key role of oracles, which enable smart contracts to use external data. However, one of the biggest challenges is ensuring the integrity of the data that oracles send to contracts, as inaccurate or manipulated information can compromise their security. This state-of-the-art review of recent works that address this issue proposes solutions such as decentralized oracles, cryptographic techniques, and data verification models to ensure the authenticity and accuracy of information. It analyzes the strengths and limitations of each approach and emphasizes areas where further progress is needed to ensure the reliability of oracles in real-world scenarios. In 2023 [23], a novel approach was presented to address the reliability of blockchain oracles, specifically regarding the validity and accuracy of off-chain data. The work proposes a graph-based profiling method, where oracles are represented as nodes, and the accumulated data validity and accuracy discrepancies are used as edge weights in the graph. This system enables the identification of trustworthy oracles and discourages the transmission of false or inaccurate data. The method was evaluated on the Ethereum network, showing a 93% accuracy in identifying reliable data sources. Additionally, the study considers the cost of running the experiments, adding a practical aspect to the proposal. This approach significantly contributes to the field by offering a dynamic and effective solution for assessing Oracle's reliability. Furthermore [24], an innovative scheme called SaNkhyA is presented, which addresses the security and reliability of data in probabilistic smart contracts (PSC) within blockchain-enabled Internet of Things (IoT) environments. This approach focuses on mitigating collusion attacks among dishonest miners, who could manipulate both contract executions and the associated data, as well as forge blocks on the blockchain. SaNkhyA is implemented in three phases: the selection of trustworthy miners, the consensus to generate random bit sequences, and the use of these sequences as input oracles for the PSCs. The evaluation of the scheme through simulations demonstrates a high resistance to collusion, reaching up to 85%, and improves scalability in block processing, with an average delay of 1.3 seconds compared to the 5.6 seconds of traditional approaches. This work represents a significant contribution to the field of trust and security in IoT oracles applied to smart contracts, enhancing both the accuracy and efficiency of decentralized systems. In the same way, in 2017 [25], one of the most widely used oracles, called Chainlink, was created. [PERSON] and [PERSON] developed this decentralized oracle system, which focuses on validating data integrity through a network of independent nodes that obtain information from multiple sources. It allows for data aggregation using consensus algorithms, minimizing the risk of errors or manipulations. Additionally, Chainlink implements incentive mechanisms that promote accuracy and penalize dishonest nodes, ensuring the quality of the information provided. Since its launch, it has established itself as the de facto standard for oracles in the blockchain ecosystem. It has been adopted in decentralized finance (DeFi), gaming, and insurance, and partnerships have been formed with significant platforms like Ethereum and Binance Smart Chain. In addition to Chainlink, other decentralized oracles use different mechanisms to validate data integrity. Band Protocol employs a data aggregation approach where nodes collect information from multiple sources and combine it through a consensus algorithm that ensures accuracy before it is delivered to smart contracts [26]. API3 allows API providers to create oracles that directly connect their data to smart contracts, which involves a quality verification process at the provider level and community auditing methods to validate the integrity of the information [27].