Identity based public key system(IDPKS) is an attractive alternative to public key cryptography. ID-PKS setting eliminates the demands of public key infrastructure(PKI) and certificate administration in conventional public key settings. Due to the absence of PKI, the revocation problem is a critical issue in IBE settings. Several IBE schemes have been proposed regarding this issue in IBE settings. ID-based encryption (IBE) allows a sender to encrypt message directly by using a receiver’s ID without checking the validation of public key certificate. Accordingly, the receiver uses the private key associated with his/her ID to encrypt such ciphertext. Since a public key setting has to provide a user revocation mechanism, the research issue on how to revoke misbehaving/compromised users. We propose a new IBE scheme with a cloud revocation authority(CRA) to solve the two shortcomings, namely the performance is significantly improved and the CRA holds only a system secret for all the users. Finally, we extend the proposed IBE scheme to present a CRA-aided authentication scheme with no period-limited privileges for managing a large number of various cloud services.