This document summarizes a research paper on secure authentication and data sharing in cloud storage using a key aggregate cryptosystem. It begins with an abstract that describes using public key cryptography to encrypt data and delegate decryption rights for any subset of ciphertexts with a constant size key. It then provides details on the proposed key aggregate cryptosystem, including an introduction, related work comparing it to other solutions, the system architecture, and sections on key aggregate encryption and a conclusion. The key aggregate cryptosystem allows a master key holder to release an aggregate key that decrypts a flexible set of ciphertexts in cloud storage while keeping other files encrypted.