Information Systems Security Boundary definition in Computer Security terms:
Definition(s): An imaginary definable perimeter encompassing all the critical functions in an INFOSEC product and separating them from all other functions within the product.
Note: INFOSEC Boundary is in terms of a product assessment; not to be confused with authorization boundary.
Source(s): CNSSI 4009-2015 (NSA Information Assurance Security Requirements Directive (IASRD) dated October, 2012)
reference: CSRC Glossary