The present invention discloses a ciphertext storage and ciphertext retrieval open cloud method and system. The system comprises a plurality of safety assemblies and a server; the server creates one encryption and decryption secret key binding with the personal identity for each login user; the server encrypts and stores the encryption and decryption secret key by using a main secret key; after the server passes the user authentication, the main secret key of the user is returned back to the safety assemblies; the safety assemblies employ the user's main secret key to perform decryption to obtain the user's encryption and decryption secret key and then employ the encryption and decryption secret key to perform encryption of the user's file to be stored and then store the file at a third-party cloud platform; and the file element data of the file to be stored and the ciphertext index of the file to be stored are generated and sent to the server; and the safety assemblies are configured to send the retrieval request to the server, and the server performs retrieval in the ciphertext index according to the keywords in the retrieval request, inquires the file element information according to the retrieval result and returns the file element information back to the user's client.