The Secure chest is a chest that is opened with a lockpick during Desert Treasure. Opening this chest requires 53 Thieving, successfully opening it gives 150 Thieving experience and yields the Gilded cross.
The chest has 3 locks, all of which must be unlocked in a row to open the chest. Failing to open one of the locks causes all the locks to reset, breaks the lockpick and deals 2-3 one-time damage to the player. It may also apply up to 6 points of recurrent poison damage on the player. After successfully unlocking this chest, it remains unlocked and can be opened without a lockpick.
The nearby Bandits may be pickpocketed for lockpicks and antipoison(1) potions.
The chance of successfully opening the secure chest is 52/256 at level 1, and 128/256 at level 99, interpolating linearly in between.
- ↑ Jagex. Mod Ash's Twitter account. 11 July 2019. (Archived from the original on 2 February 2021.) Mod Ash: "[The chance of success at the secure chest] is 20.4% at level 1 (if that were allowed), 50.2% at level 99, interpolating linearly between."