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

The best strategy to optimize data storage without compromising data retention practices is to limit the size of file attachments being sent via email. This strategy can reduce the amount of storage space required for email messages, as well as the network bandwidth consumed by email traffic. File attachments can be large and often contain redundant or unnecessary information that can be compressed, converted, or removed before sending. By limiting the size of file attachments, the sender can encourage the use of more efficient formats, such as PDF or ZIP, or alternative methods of sharing files, such as cloud storage or web links. This can also improve the security and privacy of email communications, as large attachments may pose a higher risk of being intercepted, corrupted, or infected by malware.
References:
* Data Storage Optimization: What is it and Why Does it Matter?
* Data storage optimization 101: Everything you need to know

The organization's software inventory is not complete. This finding would be of greatest concern to an IS auditor assessing an organization's patch management process because:
A software inventory is a list of all the software assets that an organization owns, uses, or manages. A software inventory is essential for effective patch management, as it helps identify the software that needs to be updated, the patches that are available, and the dependencies and compatibility issues that may arise.
Without a complete software inventory, an organization may miss some critical patches, expose itself to security risks, and waste resources on unnecessary or redundant patches.
Applications frequently need to be rebooted for patches to take effect. This finding would be of moderate concern to an IS auditor assessing an organization's patch management process because:
Rebooting applications for patches to take effect is a common and expected practice in some cases, especially for operating system or kernel patches. However, frequent reboots may indicate that the organization is not applying patches in a timely or efficient manner, or that the patches are not well-designed or tested. Frequent reboots may also cause disruption to the business operations and user experience, and increase the risk of data loss or corruption.
Software vendors are bundling patches. This finding would be of low concern to an IS auditor assessing an organization's patch management process because:
Bundling patches is a practice where software vendors combine multiple patches into a single package or update. Bundling patches can have some advantages, such as reducing the number of downloads and installations, simplifying the patch management process, and ensuring consistency and compatibility among patches. However, bundling patches can also have some disadvantages, such as increasing the size and complexity of the updates, delaying the delivery of critical patches, and introducing new bugs or vulnerabilities.
Testing patches takes significant time. This finding would be of low concern to an IS auditor assessing an organization's patch management process because:
Testing patches is a vital step in the patch management process, as it helps ensure that the patches are functional, secure, and compatible with the existing software and hardware environment. Testing patches can take significant time, depending on the scope, complexity, and frequency of the patches. However, testing patches is a necessary investment to avoid potential problems or failures that could result from applying untested or faulty patches.
References:
Best practices for patch management
Server Patch Management: Best Practices and Tools
11 Key Steps of the Patch Management Process

Following a configuration management process to maintain applications is the primary reason for ensuring proper change control. Configuration management is a process of identifying, documenting, controlling, and verifying the configuration items and their interrelationships within an IT system or environment. Following a configuration management process can help to ensure that any changes to the applications are authorized, tested, documented, and tracked throughout their lifecycle. This will help to prevent unauthorized or improper changes that could affect the functionality, performance, or security of the applications. The other options are not the primary reasons for following a configuration management process, but rather possible benefits or outcomes of doing so. References:
* CISA Review Manual (Digital Version), Chapter 4, Section 4.3.31
* CISA Review Questions, Answers & Explanations Database, Question ID 225

Controls to minimize risk and maximize value for the IT portfolio should be the most important consideration when conducting a review of IT portfolio management, because they ensure that the IT portfolio aligns with the business strategy, objectives, and priorities, and that the IT investments deliver optimal benefits and outcomes. Assignment of responsibility for each project to an IT team member, adherence to best practice and industry approved methodologies, and frequency of meetings where the business discusses the IT portfolio are also relevant aspects of IT portfolio management, but they are not as important as controls to minimize risk and maximize value. References: CISA Review Manual (Digital Version), Chapter 1, Section 1.2.3