Anti-cheat

Anti-cheat for multiplayer games. Sensitive subject — most kernel-mode anti-cheats (EAC, BattlEye, Vanguard) are loved by competitive devs and hated by privacy/Linux users. Pairs with multiplayer / netcode and distribution / stores. For full landscape see Game Development.

The 2024–26 reality: kernel-level anti-cheats remain the default for competitive PVP, despite the privacy and Linux/Steam Deck friction. Most Steam Deck-friendly esports titles ship in user-mode with EAC's user-mode option or rely on server authority + heuristics.

Free / common

★ Easy Anti-Cheat (Epic) — free with Epic Online Services. Kernel-mode by default; user-mode option (Proton-friendly, Steam Deck-compatible) was added in 2022 and is now widely used. Pair with EOS for free.
★ VAC (Valve Anti-Cheat) — free with Steamworks. Not as strong as EAC; works well for casual PVP.
Steam Datagram Relay (SDR) — free, hides server IP from clients (DDoS protection).
EOS Anti-Cheat — free, ties to EAC.

Paid commercial

BattlEye — paid, kernel-mode, used in PUBG, Rainbow Six Siege, DayZ, Arma.
Vanguard (Riot) — proprietary, kernel-mode at boot, only for Riot games. Privacy-controversial.
Hyperion (Bungie's, used in Destiny 2) — proprietary, kernel-mode.
Denuvo Anti-Cheat — paid, kernel-mode, controversial (some titles dropped it after backlash).
nProtect GameGuard — paid, dominant in Korea.
Xigncode3 — paid, used in some MMOs.

Server-side / behavioral / OSS

Cerberus (open variants) — community projects.
Anybrain, GGWP — paid SaaS that does behavioral cheat detection from server logs.
Self-built — server authority + replay validation + statistical anomaly detection. Many indie multiplayer games skip kernel AC entirely.

Anti-tampering / DRM (different problem, often packaged together)

Denuvo Anti-Tamper — paid; protects single-player games from cracks.
VMProtect, Themida — paid generic packers; sometimes used for game protection.
Steam DRM wrapper — free, light, easily cracked but raises the bar.

The Steam Deck / Linux question

Many competitive games (Apex, Fortnite Battle Royale, R6 Siege) block Linux/Proton entirely through their AC. Those that allow it use EAC user-mode or BattlEye Proton support (BattlEye added Proton-compat for some titles, opt-in per game). Indie multiplayer should default to enabling EAC user-mode + Proton compatibility unless there's a specific reason not to.

Pricing summary

Free: EAC (with EOS), VAC (with Steamworks), EOS Anti-Cheat.
Paid commercial: BattlEye, Denuvo, Hyperion, Vanguard (Riot-only), Xigncode3.
Paid SaaS behavioral: Anybrain, GGWP.

Pick this if…

Indie competitive PVP: EAC user-mode + EOS.
Casual co-op / leaderboards on Steam: VAC.
AAA Battle Royale / esports: EAC or BattlEye, expect kernel-mode.
Linux / Steam Deck friendly: EAC user-mode is the path; verify BattlEye Proton config if using it.
You don't actually need anti-cheat: save the engineering. Many indies overcorrect into AC for games where server authority is enough.