Canonum De Lex Ecclesium
Canons of Ecclesiastical Law
V. Sacraments
5.1 Sacraments
Article 142 - Obsignation
Canon 4384 (link)
Obsignation is the witnessing and sealing of a memorial by a qualified and authorized member.
Canon 4385 (link)
A Celebrant is required to notarize by Obsignatum an instrument of the Event of a sacred Sacrement where such memorialization is required as valid proof.