A compartment established at or in a safe and convenient place, in which all written matter, which pertains to the temporal as. well as the spiritual affairs of the diocese, is deposited and guarded under lock and key.
Within these archives there is another called the secret archives, in which the documents must be preserved secretly.
Canon law requires that a catalog or an index of all the documents, with a summary of the individual papers, be made.
The archives are to be locked, and permission of the bishop or of both the vicar-general and the chancellor are required for ldmission, or to take out papers.
The chancellor keeps the key.
New Catholic Dictionary