A data sharing system, comprising: members, wherein each member respectively is configured to maintain sharable private data, and to generate corresponding ciphertext index information for the shareable private data, the corresponding ciphertext index information comprising a ciphertext index of the shareable private data and information about a member that provides the shareable private data; and a sharing platform, wherein the sharing platform is connected to each member and being configured to record ciphertext index information generated by each member in an index blockchain for sharing among all members; the sharing platform configured to forward a data acquisition request initiated by a data requester member to a data provider member; the data acquisition request comprising a ciphertext index of target data, and the sharing platform further configured to forward the target data corresponding to the data acquisition request returned by the data provider member to the data requester member, wherein the target data is encrypted by an identity public key of the data requester member, characterised in that the index blockchain is configured to receive a transaction of a complaint type for the target data, wherein the transaction comprises a complaint reason and related data, and wherein the transaction invokes a smart contract for processing the complaint, and wherein the smart contract is used to verify the complaint reason based on the related data, and when the complaint reason is verified to be legitimate, an index information set corresponding to the target data shared in the index blockchain is added with an invalid identifier in the index blockchain, the index information set comprising a ciphertext index of the target data and member information of the data provider member. members, wherein each member respectively is configured to maintain sharable private data, and to generate corresponding ciphertext index information for the shareable private data, the corresponding ciphertext index information comprising a ciphertext index of the shareable private data and information about a member that provides the shareable private data; and a sharing platform, wherein the sharing platform is connected to each member and being configured to record ciphertext index information generated by each member in an index blockchain for sharing among all members; the sharing platform configured to forward a data acquisition request initiated by a data requester member to a data provider member; the data acquisition request comprising a ciphertext index of target data, and the sharing platform further configured to forward the target data corresponding to the data acquisition request returned by the data provider member to the data requester member, wherein the target data is encrypted by an identity public key of the data requester member, characterised in that the index blockchain is configured to receive a transaction of a complaint type for the target data, wherein the transaction comprises a complaint reason and related data, and wherein the transaction invokes a smart contract for processing the complaint, and wherein the smart contract is used to verify the complaint reason based on the related data, and when the complaint reason is verified to be legitimate, an index information set corresponding to the target data shared in the index blockchain is added with an invalid identifier in the index blockchain, the index information set comprising a ciphertext index of the target data and member information of the data provider member.