Assurance

Question 1

What is the point of assurance techniques for system security?

Answer 1

Assurance models allow us to assess the trustworthiness of a system. These models give us confidence (level of certainty) that a given system meets the security requirements, i.e., the security policies.

Question 2

Why do we need assurance?

Answer 2

There are several reasons for why assurance is needed since there are many ways in which a system can be unsafe. Some examples are:

• Mistakes in the systems requirements definitions
• System design flaws
• Hardware of software implementation flaws
• Operation errors and mistakes during use
• Deliberate system misuse and exploitation.

Question 3

What types of assurances are used for systems?

Answer 3

There are four main types of assurances and they address the two main aspects of the security of a given system, namely:

• Policy assurance
• Design assurance
• Implementation assurance
• Operational assurance

Question 4

What is policy assurance

Answer 4

Policy assurance is the evidence after a thorough analysis of the requirements verifying their correctness, consistency, and completeness. This evidence can be used for later evaluations of the systems level of security.

Question 5

What is Design assurance?

Answer 5

Design assurance is the evidence that the design is sufficient to meet the requirements in the policy and free of flaws.

Question 6

What is Implementation assurance

Answer 6

Implementation assurance is the evidence concerning hardware and software implementation errors and bugs an establishes whether the current implementation is consistent with the design and security requirements.

Question 7

What is operational assurance

Answer 7

Operational assurance is the evidence that the system sustains the security requirements during installation, configuration, and daily use.

Question 8

Should systems be built with security in mind from the very beginning? Name some software development models,

Answer 8

Yes, security should be an integral part of any product from the very beginning .
Two very different software developments models where security will be handles differently are:

• The waterfall life cycle model where all requirements are defines in advance,
• Extreme programming which is based on rapid prototyping and reviews using best practices.

These two models tackles assurance in different ways.