diff --git a/backend/.env.example b/backend/.env.example
index 2650e1c8..7dfd264f 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -1,6 +1,7 @@
 PORT=5000
 MONGO_URI=your_mongodb_atlas_connection_string
 JWT_SECRET=your_super_secret_key_here
+TWO_FACTOR_ENCRYPTION_KEY=your_64_character_hex_key_here # Must be a 32-byte hex key (64 hex characters)
 CLIENT_ORIGIN=your_deployed_frontend_url
 FRONTEND_URL=http://localhost:5173
 JWT_EXPIRES_IN=7d