California Code, Business and Professions Code - BPC § 5801

A Certified Interior Designer may obtain a stamp from the council that shall include a number that uniquely identifies and bears the name of that Certified Interior Designer and identifies the individual as either a Certified Interior Designer or a Certified Interior Designer with commercial designation if the Certified Interior Designer has met the requirements pursuant to paragraph (2) of subdivision (a) of Section 5811.1.  The stamp certifies that the Certified Interior Designer has provided the council with evidence of meeting the education, experience, and examination requirements pursuant to Section 5811.1.