Columbia subject headings:
Computer networks--Security measures--United States.
Computer security--United States.
Data encryption (Computer science)--United States.
Harvard subject headings:
Computer networks--Security measures--United States
Computer security--United States
Computers--Access control--United States.
Data encryption (Computer science)--United States.
Princeton subject headings:
Computer networks--Security measures--United States.
Computer security--United States.
Data encryption (Computer science)--United States.