Aggregate Signature Based Blockchain Oracle

With the promotion of blockchain technology,more and more applications require off-chain data.Since the blockchain is a deterministic closed system and the off-chain data is independent of the blockchain,blockchain oracles have become an important bridge for transferring data on and off the chain and require specific schemes to ensure the reliability of obtaining off-chain data.Therefore,it has theoretical significance and application value to study new blockchain oracle schemes.First,this paper studies the mainstream blockchain oracle scheme and proposes a blockchain multi-oracles model based on the aggregate signature.This model can compress the signature space,reduce block space overhead and communication load,and uses multiple oracles to avoid single points of failure.Besides,for request data with complex processes or different degrees of importance,two different multi-oracles integration models based on aggregated signatures are proposed.Secondly,for the same type of request data,this paper proposes a blockchain oracle scheme based on RSA sequence aggregation signature,which uses the delayed verification feature of the signature algorithm to speed up the aggregation signature,and the scheme requests external data from high-reputation blockchain oracles,uses the reputation mechanism to encourage each oracle to return the correct data and uses data aggregation to filter malicious data.Then,for the unique and important request data,a new blockchain oracle scheme based on BLS aggregation signature is proposed.Specifically,the scheme not only uses BLS aggregate signature to reduce the storage cost,but also uses commitment mechanisms to improve the fault tolerance of the blockchain oracle scheme.Both of the proposed schemes can ensure that off-chain data can be transferred into the blockchain in a trusted and reliable way.Finally,using smart contracts to experiment and analyze the results of blockchain oracles schemes,and test the transaction costs,storage costs,verification costs,total costs and different data aggregation methods of blockchain oracles schemes.Experimental results show that this scheme can meet practical application requirements.