The invention discloses an 
encryption and search method for revocable 
keyword search public keys in 
cloud storage and belongs to the technical field of 
network security. The method includes: setting 
system public parameters and dividing 
system time into z time segments, and creating a public-private key pair at a 
client; when data storage requests occurs, selecting a keyword collection of a 
data file, selecting optional symmetrical 
encryption algorithm to encrypt the 
data file, utilizing the public key and the 
current time segment to encrypt the keyword collection, and transmitting the encrypted keyword collection to the 
cloud server; when the next 
time segment arrives, generating keyword collection 
cipher again, and updating the 
cloud server on a 
server; when a 
keyword search request occurs, by the 
client, utilizing the private key and the 
current time segment to calculate 
trap door information of the keywords, transmitting the 
trap door information to the 
cloud server, and by the cloud 
server, obtaining the search results and sending back file 
cipher containing the search keywords to users. The 
encryption and search method is suitable for 
cloud storage with high safety requirements, safe, and efficient, and has the capability of revoking 
server search.