The protection of data against unauthorized access. Programs and data can be secured by issuing passwords and digital certificates to authorized users. However, passwords only validate that a correct number has been entered, not that it is the actual person. Digital certificates and biometric techniques (fingerprints, eyes, voice, etc.) provide a more secure method (see authentication). After a user has been authenticated, sensitive data can be encrypted to prevent eavesdropping (see cryptography).Authorized Users Can Be the Most DangerousAlthough precautions can be taken to authenticate users, it is much more difficult to determine if an authorized employee is doing something malicious. Someone may have valid access to an account for updating, but determining whether phony numbers are being entered requires a great deal more processing. The bottom line is that effective security measures are always a balance between technology and personnel management. See Parkerian hexad, information assurance, security scan, security audit, audit trail, NCSC, ICSA, access control, share-level security, user-level security and social engineering.