The Unlocking Charm (Alohomora),
also known as the Thief's Friend,
was a charm that unlocked objects such as doors or windows. It was also able to open doors locked by the Locking Spell (Colloportus),
and as such, acted as its counter-charm.
The Anti-Alohomora Charm could be used to prevent this charm from working on a locked target.
INCANTATION: Alohomora (ah-LOH-ho-MOR-ah)
HAND MOVEMENT: Unlocking-spell
LIGHT: Invisible, blue, yellow, or purple
EFFECT: Unlocks objects
CREATOR: Ancient African sorcerer (possibly); first brought to Britain by Eldon Elsrickle in the early 1600s.