The encryption keys are tied to specific game builds. A key that works for GTA V version 1.0.1868 (The Doomsday Heist) will work for version 1.0.2699 (The Contract DLC). If you download a random encryption-key.bin from a website from 2018, you will likely corrupt your update.rpf archive, forcing you to verify game files or reinstall.
(GTA V). Specifically, it is a binary file containing the cryptographic keys necessary for the software to read game assets like textures, models, and audio. encryption-key.bin gta v