Q: Is an ambry supposed to be secured under lock and key?
A: The code of canon law says the pastor is to preserve the oils “diligently with proper care.” The US edition of the Book of Blessings include the Order for the Blessing of a Repository for the Holy Oils. It says “This repository should be secure and be protected by a lock” (1125). But that is not universal law.
Some places do not have an ambry that locks but place it in a room that locks or inside a church that is kept secure.