Congregation for Divine Worship and the Discipline of the Sacraments, Response to a dubium Concerning Safeguarding the Tabernacle Key, 1997.
What are the regulations pertaining to the safeguarding of the tabernacle key?
Response. The rite entitled “Holy Communion and Worship of the Eucharist Outside Mass” promulgated on June 21, 1973 declares: “The key of the tabernacle where the Blessed Eucharist is reserved must be diligently safeguarded by the priest who has charge of the church or oratory or by the extraordinary minister who has been given the faculty of distributing Holy Communion” (no. 10). In a like manner the Code of Canon Law establishes in c. 938, §5: “The person responsible for the church or oratory is to take care that the key of the tabernacle in which the Most Holy Eucharist is reserved is safeguarded most diligently.”
Notitiae 33 (1997): 31; W.H. Woestman, Sacraments: Initiation, Penance, Anointing of the Sick: Commentary on Canons 840-1007 (Ottawa, Saint Paul University, Faculty of Canon Law, 2004): 422.