A Secure Data Transmission Framework for Cloud-Based Communication Systems

Abstract

Cloud-based communication systems allow users and organizations to exchange and store information through elastic, remotely managed infrastructure, but the separation between data owners and cloud resources increases exposure to interception, unauthorized access, key compromise, and undetected modification. This methodology paper proposes a layered secure data transmission framework that combines authenticated user access, per-session symmetric encryption, protected key exchange, transport-layer security, integrity verification, nonce-based replay protection, and auditable cloud storage. The central data-protection primitive is AES-256 in Galois/Counter Mode (AES-256-GCM), selected because it provides confidentiality and authenticated integrity in a single operation. Session keys are wrapped using an asymmetric key mechanism or a managed key service, while role-based access control limits decryption privileges. The methodology evaluates the design through a controlled prototype benchmark using 1, 5, 10, and 25 MB payloads, median execution time over seven runs, byte overhead, and active tampering tests. In the test environment, AES-256-GCM required 41.68 ms to encrypt 10 MB and 105.37 ms to encrypt 25 MB, while adding only 28 bytes for nonce and authentication tag. A conventional AES-CBC plus HMAC-SHA-256 pipeline required 163.75 ms and 413.98 ms for the same payloads and added 64 bytes. One hundred modified-ciphertext trials and one hundred wrong-key trials were rejected by GCM authentication. The results indicate that an authenticated-encryption-centered framework can improve transmission protection while maintaining low communication overhead and practical computational cost.