Explanation/Reference:
Explanation:
An extranet server should be placed on a screened subnet, which is a demilitarized zone (DMZ). Placing it on the Internet side of the firewall would leave it defenseless. The same would be true of placing it on the external router, although this would not be possible. Since firewalls should be installed on hardened servers with minimal services enabled, it would be inappropriate to store the extranet on the same physical device.

Explanation
The fundamental purpose of establishing security metrics is to provide feedback on the effectiveness of the information security controls and processes. Security metrics are quantitative or qualitative measures that indicate how well the organization is achieving its security objectives and goals. Security metrics can help the information security manager to monitor, evaluate, and improve the performance of the information security program, as well as to identify gaps, weaknesses, and areas for improvement. Security metrics can also help the organization to demonstrate compliance with internal and external standards, regulations, and best practices. Increasing return on investment (ROI), adopting security best practices, and establishing security benchmarks are possible outcomes or benefits of using security metrics, but they are not the fundamental purpose of establishing them. References = CISM Review Manual, 16th Edition, pages 46-471; CISM Review Questions, Answers & Explanations Manual, 10th Edition, page 642 Learn more:
1. isaca.org2. amazon.com3. gov.uk
Security metrics are used to measure the effectiveness of controls and evaluate the overall security posture of an organization. This feedback provides an understanding of the progress made towards achieving security objectives and allows organizations to make necessary adjustments.

Section: INFORMATION SECURITY PROGRAM DEVELOPMENT
Explanation:
Public key infrastructure (PKI) combines public key encryption with a trusted third party to publish and revoke digital certificates that contain the public key of the sender. Senders can digitally sign a message with their private key and attach their digital certificate (provided by the trusted third party). These characteristics allow senders to provide authentication, integrity validation and nonrepudiation. Symmetric cryptography provides confidentiality. Mashing can provide integrity and confidentiality. Message authentication codes provide integrity.