Research on the Restricted Sharing Technology of Private Credit Data Based on Blockchain

doi:10.3969/j.issn.1671-1122.2022.05.007

Abstract

Abstract:

With the development of credit system, the digitization of credit data is an inevitable choice to promote the construction of social credit. At present, user credit data is mainly stored in clear text in centralized credit institutions, which has the problems of difficult sharing and poor security. Thanks to the traceability and non tamperability of blockchain, it provides a new distributed storage solution for the credit field. Combined with blockchain, homomorphic encryption algorithm, access control algorithm and asymmetric algorithm, this paper proposed a blockchain model of limited data sharing and privacy protection. In the model, the credit data was encrypted by calling ECC asymmetric algorithm and sent to the cloud server. CKKS algorithm in seal database was introduced into the cloud for homomorphic encryption, which solved the pain point of high overhead in ciphertext calculation. Took the blockchain certificate issuing center as the trusted third party to complete the initialization, key generation and distribution of the improved access control algorithm CP-ABE. Finally, deposit the credit data on the blockchain. The system implemented by this model can ensure fine-grained access control and privacy protection of user rights. The function and performance evaluation shows that the method proposed in this paper has good reference significance and application value in the field of privacy protection, credit deposit and access control in the field of digital credit. The application system throughput and blockchain TPS can meet the needs of practical application performance.

Key words: digital credit, blockchain, homomorphic encryption, access control, asymmetric encryption

CLC Number:

TP309

LIU Jiawei, MA Zhaofeng, WANG Shushuang, LUO Shoushan. Research on the Restricted Sharing Technology of Private Credit Data Based on Blockchain[J]. Netinfo Security, 2022, 22(5): 54-63.

Figures/Tables 15

References 20

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符号	符号定义
$P{{K}_{C}}$	信用系统（Credit System）公钥
$M{{K}_{C}}$	信用系统主密钥
$\lambda $	信用系统安全参数
$P$	素数域
$lis{{t}_{auth}}$	权限撤销列表,记录用户权限是否被取消
$prime$	用户唯一的素数
${{U}_{Gid}}$	用户Gid,由CA提供,保证用户全局唯一性
${{U}_{att}}$	用户的相应属性
${{S}_{att}}$	用户的属性集
${{M}_{C}}$	待加密的信用明文
$AC{{S}_{P}}$	系统用户访问策略的访问控制结构
${{C}_{C}}$	基于CP-ABE属性的加密密文
$U{{K}_{C}}$	信用系统用户密钥
$DO$	信用数据拥有者

符号	符号定义
$E{{p}_{\left( a,b \right)}}$	椭圆曲线,其中p会取一个相当大的数
$k$	用户的私有密钥,是椭圆曲线上的点
$G$	椭圆曲线上的基点
$K$	用户的公开密钥,由私钥生成
$M$	信用数据编码后所得数据
$r$	编码后产生的随机数
${{C}_{n}}$	编码数据使用椭圆曲线加密算法加密所得

用户数/个	接收/tps	带宽/MB
100	254,387	100
500	252,463	100
1000	254,257	100