Explanation
Two-factor authentication provides an additional security mechanism over and above that provided by passwords alone. This is frequently used by mobile users needing to establish connectivity to a corporate network. IP address packet filtering would protect against spoofing an internal address but would not provide strong authentication. An intrusion detection system (IDS) can be used to detect an external attack but would not help in authenticating a user attempting to connect. Digital signatures ensure that transmitted information can be attributed to the named sender.

Section: INFORMATION RISK MANAGEMENT

Section: INFORMATION SECURITY GOVERNANCE
Explanation:
Without the support of senior management, an information security program has little chance of survival. A company's leadership group, more than any other group, will more successfully drive the program. Their authoritative position in the company is a key factor. Budget approval, resource commitments, and companywide participation also require the buy-in from senior management. Senior management is responsible for providing an adequate budget and the necessary resources. Security awareness is important, but not the most important factor. Recalculation of the work factor is a part of risk management.