区块链数据保密查询的不经意传输协议

在区块链数据存储与查询过程中，由于区块链的透明性和公开性，全网所有用户均有可能获取查询者的数据信息，存在泄漏查询者隐私数据的风险。采用区块链链上-链下存储思想，设计区块链数据存储模型，引入代理重加密机制，将存储者加密后的数据分布式存储在链下，将存储者发送的索引信息和Merkle树根哈希值存储在链上，确保了数据的完整性、可靠性和可验证性，并减少了区块链数据对存储资源的占用。利用椭圆曲线加密算法设计区块链数据保密查询的不经意传输协议，使得全网所有用户均无法获取查询者的数据信息，保护了区块链数据传输过程中查询者的隐私。分析结果表明，该协议中查询者完成一次区块链上的不经意传输仅需2n+2k+2次椭圆曲线乘法运算，相比于现有不经意传输协议具有存储空间小、计算复杂度低等优势，并且在相同长度的密钥下具有更高的安全性。

Oblivious Transfer Protocol for Confidentiality Query of Blockchain Data

During the data storage and query of a blockchain, owing to the transparency and openness of the blockchain, all users of a network may obtain information regarding the inquirer;thus, confidential information regarding the inquirer may be exposed.This study adopts the idea of a blockchain on-chain off-chain storage, designs a blockchain data storage model, introduces a proxy re-encryption mechanism for storing the encrypted data of the storer off-chain in a distributed manner, and stores the index information sent by the storer as well as the hash value of the root of the Merkle tree on the chain;this, in turn, ensures the integrity, reliability, and verifiability of data and also reduces the utilization of storage resources by the blockchain data.The elliptic curve encryption algorithm is used to design an Oblivious Transfer(OT) protocol for the confidential query of blockchain data, which prevents all the users in the entire network from obtaining the inquirer's information;this protects the privacy of the inquirer during data transmission.Analysis results reveal that the inquirer requires only 2n+2k+2 elliptic curve multiplication operations to complete an OT on the blockchain when using this protocol.Compared with existing protocols, this OT protocol requires a smaller storage space, features lower computational complexity, and offers higher security for the same key length.