Disclosed is a data management method. The method comprises: a client can determine a ciphertext index value according to information on plaintext data, and send the ciphertext index value to a cloud device; the cloud device can establish, in an index structure (such as a B-tree), a correspondence between the ciphertext index value and information on a storage location of ciphertext data corresponding to the plaintext data, or search an index structure for a storage location of ciphertext data according to the ciphertext index value, so as to implement an operation on the ciphertext data. In the present application, a ciphertext index value is used to replace a field in a data column to serve as a key value in a conventional ordered index, so as to implement searching of ciphertext data, and order-based query can be performed on ciphertext data stored in a table without adding any data table field, thereby reducing space occupied by a full table used for storing the ciphertext data and improving the expandability for stored data in a cloud device.