Confidentiality, Integrity, Availability: The three components of the CIA Triad

In this post, I shall be exploring one of the fundamental concepts of security that should be familiar with most security professionals and students: the CIA triad.

What is the CIA triad? No, CIA in this case is not referring to the Central Intelligence Agency. CIA refers to Confidentiality, Integrity and Availability. Confidentiality of information, integrity of information and availability of information. Many security measures are designed to protect one or more facets of the CIA triad. I shall be exploring some of them in this post.

When we talk about confidentiality of information, we are talking about protecting the information from disclosure to unauthorized parties.

Information has value, especially in today’s world. Bank account statements, personal information, credit card numbers, trade secrets, government documents. Every one has information they wish to keep a secret. Protecting such information is a very major part of information security.

A very key component of protecting information confidentiality would be encryption. Encryption ensures that only the right people (people who knows the key) can read the information. Encryption is VERY widespread in today’s environment and can be found in almost every major protocol in use. A very prominent example will be SSL/TLS, a security protocol for communications over the internet that has been used in conjunction with a large number of internet protocols to ensure security.

Other ways to ensure information confidentiality include enforcing file permissions and access control list to restrict access to sensitive information.

This is an excellent question on Security.Stackexchange that covers how to keep important information confidential. Similar questions can be found here.

Integrity

Integrity of information refers to protecting information from being modified by unauthorized parties.

Information only has value if it is correct. Information that has been tampered with could prove costly. For example, if you were sending an online money transfer for $100, but the information was tampered in such a way that you actually sent $10,000, it could prove to be very costly for you.

As with data confidentiality, cryptography plays a very major role in ensuring data integrity. Commonly used methods to protect data integrity includes hashing the data you receive and comparing it with the hash of the original message. However, this means that the hash of the original data must be provided to you in a secure fashion. More convenient methods would be to use existing schemes such as GPG to digitally sign the data.

Availability

Availability of information refers to ensuring that authorized parties are able to access the information when needed.

Information only has value if the right people can access it at the right times. Denying access to information has become a very common attack nowadays. Almost every week you can find news about high profile websites being taken down by DDoS attacks. The primary aim of DDoS attacks is to deny users of the website access to the resources of the website. Such downtime can be very costly. Other factors that could lead to lack of availability to important information may include accidents such as power outages or natural disasters such as floods.

How does one ensure data availability? Backup is key. Regularly doing off-site backups can limit the damage caused by damage to hard drives or natural disasters. For information services that is highly critical, redundancy might be appropriate. Having a off-site location ready to restore services in case anything happens to your primary data centers will heavily reduce the downtime in case of anything happens.

Conclusion

The CIA triad is a very fundamental concept in security. Often, ensuring that the three facets of the CIA triad is protected is an important step in designing any secure system. However, it has been suggested that the CIA triad is not enough. Alternative models such as the Parkerian hexad (Confidentiality, Possession or Control, Integrity, Authenticity, Availability and Utility) have been proposed. Other factors besides the three facets of the CIA triad are also very important in certain scenarios, such as non-repudiation. There have been debates over the pros and cons of such alternative models, but it is a post for another time.

Thank you for reading.