## 1 Introduction  
Currently, data have become something within people's reach, and more and more people are becoming aware of the ownership and usage of their data. What is \"data confirmation\"? The purpose of data confirmation is to legally establish ownership of the data and the right of the data owner to determine who can have access to the data. Data confirmation requires determining the type of rights, how they will be acquired, and how they will be distributed. With the popularity of cloud computing, people have begun to share data. There are many ways to share data, such as uploading to third-party trading platforms, cloud servers, Github [1], etc., resulting in the inability to ensure the privacy of users. Many scholars have begun to study data sharing, privacy issues [2; 3], and how data are uploaded. In addition, the speed of data dissemination is extremely fast. [PERSON] et al. [4] modeled network public opinion data to predict public opinion crisis warnings. [PERSON] et al. [5] proposed a more comprehensive recommendation scheme based on real-world shared mobile data. The proposal of ciphertext-policy attribute-based encryption provides a good answer to these problems. CP-ABE allows the data owner to specify that only those who conform to the access policy can access the data. Figure 1 shows the execution process of CP-ABE. The data owner [PERSON] has some data (_defined in the figure as \"Data\"_), and she sets a set of access policies (\((A\wedge B)\vee(C\wedge D)\) in the figure) according to the potential user subjectively, and combines _Data_ with access policies to encrypt and upload to the server. At this time, there are two users _User\({}_{1}\)_ and _User\({}_{2}\)_ in the system; _User\({}_{1}\)_ has attributes \(A\) and \(B\), and _User\({}_{2}\)_ has attributes \(A\) and \(C\), then according to the access policies in the ciphertext, _User\({}_{1}\)_ can decrypt and access the data, but _User\({}_{2}\)_ fails to decrypt. However, due to the replicability of the data, ownership of the data cannot be determined. The development of blockchain [6; 7; 8] has brought the possibility of data rights confirmation. Due to its immutability and traceability, the information of the data owner cannot be tampered with once it is on the chain, and it can be easily traced back to the source and destination of the data. However, as a result of the decentralized and public nature of blockchain technology, the privacy of the data owner cannot be guaranteed. Using traditional third-party hosting or issuing certificates of ownership does not guarantee that the data owner's source data will not be leaked. Therefore, there is the need of a scheme that solves the above problems. Consider the following scenario: [PERSON] wants to store her data on the cloud and share them with others, but she only wants a specific group of people to access the data. Therefore, she specifies an access policy and encrypts the data using CP-ABE before uploading it. [PERSON] is a member of [PERSON]'s designated group, and he retrieves and decrypts the data from the cloud. [PERSON] is [PERSON]'s friend, but he is not a part of the designated group. [PERSON] contacts [PERSON] and obtains a copy of the data. One day, [PERSON] discovers that [PERSON] is using her data and wants to seek compensation. However, [PERSON] claims that the data are his own. How can [PERSON] prove that the data belong to her? In 2005, [PERSON] and [PERSON] [9] introduced the notion of fuzzy identity-based encryption. which was later extended to attribute-based encryption (ABE). In an ABE system, the ciphertext and key are associated with the attribute set and access structure, and decryption only succeeds when the attribute set satisfies the access structure. [PERSON] et al. [10] suggested correlating the access policy with the ciphertext and key, respectively, and divided ABE for the first time into ciphertext-policy attribute-based encryption (CP-ABE) and key-policy attribute-based encryption (KP-ABE) in 2006. [PERSON] et al.