Columbia subject headings:
Computers--Access control--Congresses.
Cryptography--Congresses.
Data transmission systems--Security measures--Congresses.
Harvard subject headings:
Computers--Access control--Congresses.
Cryptography--Congresses
Data transmission systems--Security measures--Congresses.
Princeton subject headings:
Computers--Access control--Congresses.
Cryptography--Congresses.
Data transmission systems--Security measures--Congresses.