| At present,in the process of the development of small and medium-sized enterprises,the difficulty in financing and the low utilization rate of funds are the important problems that trouble the development of small and medium-sized enterprises,and the key to solve this problem is to improve the flow of financial data between enterprises.One of the ways to solve the above problems is to form a group of enterprises with frequent business exchanges and realize mutual assistance among enterprises with the help of group loan system.However,the existing group loan system is also deficient in many aspects: On the one hand,the loan information is given to the bank or the third party manager for supervision and management,which leads to low loan efficiency and a large amount of additional costs in terms of time and manpower.In addition,the data records cannot be guaranteed,and there exists the situation that the recorded information is deleted or modified maliciously.On the other hand,information is not shared among the loan institutions within the group,which leads to the occurrence of security accidents such as malicious loans from members and overdraft of enterprise capital chain.With the emergence and development of bitcoin,blockchain as its supporting technology has attracted extensive attention from all walks of life.Blockchain technology was initially only used for virtual currencies,but with the deepening of its research,blockchain technology has gradually been extended to other aspects of the financial sector.The decentralized financial system based on blockchain technology has been successively launched,which has greatly improved the flow efficiency of capital and information and saved a lot of time and labor costs.In this article,we apply blockchain technology to group lending and combine blockchain with Trusted Execution Environment(TEE).This paper realizes the automatic determination of loan conditions and the automatic execution of intelligent contracts,constructs a group loan system based on blockchain,and solves the problems of low loan efficiency,loan information disclosure and malicious loans of users existing in the traditional group lending system.The specific work is as follows:1.The scheme is divided into four stages: member joining,loan application,repayment and overdue liability recovery.In the member joining stage,the linkable group signature technology is used to verify the member joining the group,and the group administrator manages the member information.In the loan application stage,the homomorphic encryption technology is used to package and encrypt the loan application information of the user and calculate the loan amount in secret state.The administrator determines whether the loan amount meets the requirements,decides whether to send it to the loan company,and finally records it on the blockchain.In the repayment stage,the repayment information shall be recorded on the blockchain after being confirmed by the administrator.In the stage of overdue loan recovery,the linkability and traceability of linkable group signature are used for loan recovery.2.In the system implementation stage,the system connects the JUICE blockchain platform and TEE platform to edit the intelligent contract algorithm.The system realizes the functions of setting up the loan application package,uploading the blockchain,encrypting and calculating the loan amount,and auditing the loan amount.The system tested the time efficiency and gas cost of each algorithm,and used the eclipse platform to simulate the Android function items.This paper introduces in detail the interaction process between borrowers and lenders on the premise of protecting users' privacy.The overall program improves the group loan efficiency,effectively prevents users from malicious loans and duplicate loans,and protects the rights and interests of both parties.In this paper,the security analysis and performance evaluation of the scheme design are carried out,and the automatic lending function of the system is realized. |
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