Fecha de publicación: 10/07/2020 Fuente: Wipo "BigData" The invention relates to the technical field of data security, in particular to a ciphertext retrieval method for security authentication of big data, which comprises the following steps: firstly, a key generation center generates a key and sends the key to a cloud computing provider, a cloud platform, a data owner and a data user; then, the data owner generates a dictionary and an index, generates a user authorization certificate and a ciphertext data packet and sends out the user authorization certificate and the ciphertext data packet; then the data user uses a public key of a homomorphic encryption weak key to encrypt a searched keyword to generate a trap door and sends the trap door and the number k of files needing to be returned to the cloud platform; then, the cloud platform and the cloud computing provider interactively and cooperatively compute a ciphertext correlation score; and finally, the data user decrypts the ciphertext correlation score according to the obtained user authorization certificate to obtain a ciphertext file. According to the method, the user authorization certificate is designed to realize management of a user key, and meanwhile, homomorphic encryptionis used, so that a retrieval result is ensured to be in a ciphertext form, and the first k ciphertext documents are ensured to be returned and decrypted according to a related score sequence.