This document summarizes several papers related to identity-based encryption in cloud computing. It discusses issues with revocation in identity-based encryption systems and proposes outsourcing key generation operations to reduce overhead for the private key generator. The document reviews different approaches to managing revocation and proposes a revocable identity-based encryption scheme that securely outsources computations. It also surveys other identity-based encryption schemes, including those addressing hierarchical identities, fuzzy identities, and schemes without pairings.