This document discusses data security in cloud computing environments using encryption techniques. It proposes a system that encrypts and decrypts text files using AES encryption to securely store and access data in the cloud. The system provides three main functions: registration and login for user authentication, encryption of selected files before uploading to the cloud, and decryption of encrypted files downloaded from the cloud. Encrypting data in the cloud with AES aims to ensure confidentiality, integrity and availability of user information.