Trusted Blockchain Oracle Scheme Based on Aggregate Signature

Abstract

With the development of blockchain technology, more and more applications need out-of-chain data. Thus, blockchain oracles have become an important bridge for transferring data on and off the chain. This paper studies the mainstream blockchain oracles scheme, summarizes the shortcomings of the existing schemes and proposes a new blockchain oracle scheme based on BLS (Bohen-Lynn-Shacham) aggregation signature to ensure that off-chain data can be transferred into the blockchain in a trusted and reliable way. Specifically, the scheme uses multiple blockchain oracles to avoid the single point of failure or even a small number of malicious oracles, and improve the credibility of data. At the same time, it not only uses BLS aggregate signature to reduce the storage cost and communication overhead, but also uses commitment mechanisms to ensure the reliability and authenticity of the data. Besides, the simulation results show that the scheme can meet the practical application requirements.

Blockchain Oracles: State-of-the-Art and Research Directions

“…This additional expense along with Oraclize's profit itself raises the total cost of employing Oraclize, which end users (calling contract) are obliged to pay. According to [18] it can only be used in Ethereum, it is also expensive and relies on a single data source.…”

“…This may seem a good solution however, there are several drawbacks: SGX suffers from several security vulnerabilities also being a centralized solution; Town Crier is prone to SPOF. Another limitation is that Town Crier supports limited types of API's and is exclusively built for Ethereum [39], [18].…”

“…According to Microsoft researcher David Rothchild, in an article at Wired "the instability of Ethereum tokens that users would employ in their bets could be deemed a flaw that could compromise their accuracy". Liu and Feng [18] claimed that the design mechanism of Augur's consensus is predicively low in efficiency, platform's scaling restricts prediction accuracy and uneven token distribution tarnishes prediction results' credibility.…”

“…Muhlberger et al [17] studied Oracles patterns in two dimensions: inbound and outbound data flow (flow direction) and the data flow initiator, whether in push-or pull-based communication. Liu and Feng [18] studied the mainstream blockchain Oracles scheme and proposed a new blockchain Oracles scheme based on the Bohen-Lynn-Shacham aggregation signature that ensures the trusted and reliable transmission of off-chain data into the blockchain. On the other hand, Al-Breiki et al [9] have analyzed and presented trust-enabling features in the Oracles used in blockchain ecosystems.…”

Fine-grained Access Control Method for Blockchain Data Sharing based on Cloud Platform Big Data

“…Blockchain technology is a trusted storage network composed of distributed equal nodes, consisting of tamperproof block data and automatically executable smart contract code, which has the characteristics of tamper-proof, coordination autonomy, high security, and trust of decentralized decision-making [6]. In the research of data sharing mechanisms based on blockchain, Dai Mingjun et al [7] promoted the storage space of blockchain through distributed storage (DS) based on network coding (NC).…”