Encrypting and Validating Save Data

This chapter explains how save data can become a major attack surface in single-player games when players edit files to gain resources, unlock content, bypass progression, or exploit rollback behavior. It introduces a cryptographic save protection model built around confidentiality, integrity, authenticity, and version compatibility. The chapter presents the concept of a secure save envelope that combines AES encryption, HMAC validation, salts, initialization vectors, and derived keys to protect gameplay data from being read or modified. It also explains secure save writing and loading workflows, including validation steps that reject corrupted or tampered files. Through case studies, the chapter shows how unprotected save systems can damage progression, balance, and player perception. Overall, the chapter establishes encrypted and validated save data as a foundation for preserving game integrity.