Lockpicking is a skill in which an individual uses instruments to break a locking mechanism and gain access to either a location, or to take items of worth from a container. As such, it was adopted by both the Assassins and Templars.
During the Renaissance, the Assassin Ezio Auditore da Firenze used his Hidden Blade to unlock and enter certain secret locations which usually kept desirable objects away from the attention of the general populace.
During his search for the Masyaf Keys, Ezio used the Hookblade created by the Ottoman Assassins to gain access to several secret locations across the Constantinople, in a manner similar to picking a lock with the Hidden Blade.
During the 18th century, lockpicking became more of an interactive endeavor, which required two instruments to find the locking and raking angles inside the keyhole of a doorframe or chest, before physical force was required to break the mechanism within. The Assassin-turned-Templar Shay Cormac used considerable brute force when lockpicking barred doors. Both Haytham Kenway and his son Connor were shown to be skilled lockpickers. During the French Revolution, Arno Dorian used lockpicking to open doors and chests, eventually becoming a skilled lockpicker well into his tenure as an Assassin.