Information is expanding day by day and it comes with irrelevance and lack of security. Also, it is mandatory to reduce time complexity by providing relevant results to users so that they can directly access the services on the cloud based on pay per usage policy. The paper proposes an ontology-based algorithm to perform encryption and decryption of input data in a multi-tenant cloud environment. It involves the classification of classes, properties, and instances of plain text by designing ontology related to a specific domain. The ontology is designed with the help of an ontology editor called Protégé and performs accessing of relevant data from cloud service providers on pay per usage policy.