This method is known as creating a digital signature of the message. It ensures the integrity of the message by verifying that it has not been tampered with in transit. The process involves hashing the message and encrypting the hash value with the sender's private key. Any changes to the message will result in a different hash value1. This method is used in DomainKeys Identified Mail (DKIM), which verifies an email's domain and helps show that the email has not been tampered with in transit2.
References:
Understanding Digital Signatures | CISA
Using DomainKeys Identified Mail (DKIM) in your organisation

When storage space is limited,incremental backupsare the most efficient because they store only the changes made since the last backup, reducing storage requirements.
Option A (Correct):Incremental backupsonly store data that has changed since the last backup, significantly reducing storage usage while maintaining a historical record of changes.
Option B (Incorrect):Mirror backupscreate an exact copy of the entire system, consuming significant storage space andnot retaining historical versions.
Option C (Incorrect):Full backupscapture everything and require large amounts of storage, making them impractical for space-constrained environments.
Option D (Incorrect):Annual backupsrefer to frequency rather than method. They do not inherently optimize storage usage.
Reference:ISACA CISA Review Manual -Domain 4: Information Systems Operations and Business Resilience- Covers backup strategies, storage management, and disaster recovery.

A business impact analysis (BIA) is a process that identifies and evaluates the potential effects or consequences of disruptions or disasters on an organization's critical business functions or processes. A BIA can help prioritize the recovery of critical functions by assessing their importance and urgency for the organization's operations, objectives, and stakeholders, and determining their recovery time objectives (RTOs), which are the maximum acceptable time for restoring a function after a disruption. A business continuity plan (BCP) testing is a process that verifies and validates the effectiveness and readiness of a BCP, which is a document that outlines the strategies and procedures for ensuring the continuity of critical business functions in the event of a disruption or disaster. A BCP testing does not prioritize the recovery of critical functions, but rather evaluates how well they are recovered according to the BCP. A disaster recovery plan (DRP) testing is a process that verifies and validates the effectiveness and readiness of a DRP, which is a document that outlines the technical and operational steps for restoring the IT systems and infrastructure that support critical business functions in the event of a disruption or disaster. A DRP testing does not prioritize the recovery of critical functions, but rather evaluates how well they are supported by the IT systems and infrastructure according to the DRP. A risk assessment is a process that identifies and analyzes the potential threats and vulnerabilities that could affect an organization's critical business functions or processes. A risk assessment does not prioritize the recovery of critical functions, but rather estimates their likelihood and impact of being disrupted by various risk scenarios.

Wireless security relies onstrong encryptionto prevent unauthorized access and data interception.
Option A (Correct):WPA3is thelatest and most secureWi-Fi encryption standard, offeringstronger protectionagainst brute-force attacks and improvingkey management.
Option B (Incorrect):DES is outdatedand vulnerable tomodern attacks, making it unsuitable for wireless security.
Option C (Incorrect):WEP is highly insecuredue toweak encryptionand can be cracked inminutesusing basic tools.
Option D (Incorrect):SSL secures web traffic, notwireless networks.
Reference:ISACA CISA Review Manual -Domain 5: Protection of Information Assets- Coverswireless security, encryption, and network security best practices.

The best recommendation is to place an intrusion detection system (IDS) between the firewall and the Internet. An IDS is a device or software that monitors network traffic for malicious activity and alerts the network administrator or takes preventive action. By placing an IDS between the firewall and the Internet, the IS auditor can enhance the security of the network perimeter and detect any attack attempts that the firewall was unable to recognize.
The other options are not as effective as placing an IDS between the firewall and the Internet:
Placing an IDS between the firewall and the organization's web server would not protect the web server from external attacks that bypass the firewall. The web server should be placed in a demilitarized zone (DMZ), which is a separate network segment that isolates public-facing servers from the internal network.
Placing an IDS between the firewall and the demilitarized zone (DMZ) would not protect the DMZ from external attacks that bypass the firewall. The DMZ should be protected by twofirewalls, one facing the Internet and one facing the internal network, with an IDS monitoring both sides of each firewall.
Placing an IDS between the firewall and the organization's network would not protect the organization's network from external attacks that bypass the firewall. The organization's network should be protected by a firewall that blocks unauthorized traffic from entering or leaving the network, with an IDS monitoring both sides of the firewall.