Understanding the Security Triad
When studying for just about any security related exam including Security+, CASP, SSCP, and CISSP, you’ll come across confidentiality, integrity, availability as three core concepts that are commonly referred to as the security triad and their importance cannot be overstated. You might also hear the trio referred to as the CIA security triad or the AIC security triad.
Confidentiality ensures that data is only viewable by authorized users. In other words, the goal of confidentiality is to prevent the unauthorized disclosure of information. Loss of confidentiality indicates that unauthorized users have been able to access information.
If there is a risk of sensitive data falling into the wrong hands, it should be encrypted to make it unreadable. This includes encrypting data at rest and data in motion. Data at rest is any data stored as a file on a hard drive, mobile device, or even a USB flash drive. Data in motion is any data traveling over a network. AES is the most common symmetric encryption protocol used to encrypt data at rest. SSH, IPsec, SSL, and TLS are some common encryption protocols used to encrypt data in motion.
Additionally, data should be protected with access controls to enforce confidentiality.
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The goal of integrity is to verify that data has not been modified and loss of integrity can occur through unauthorized or unintended changes. Integrity is commonly enforced by controlling data to prevent it from being modified, and by using hashes. Hashing algorithms such as MD5, HMAC, or SHA1 can calculate hashes to verify integrity.
A hash is simply a number created by applying the algorithm to a file or message. No matter how many times you calculate a hash, it will always be the same when calculated on the same data. However, if the data changes and you recalculate the hash, the hash will different.
Hashes are calculated at different times and then compared to each other to verify that integrity has been maintained. For example, if you calculate a hash on a file on Monday and it is 123456, and then you recalculate the hash on Wednesday and it is still 123456, you know that the data is the same. However, if you calculate the hash on Friday and it is 459459, you know that the data is no longer the same because the two hashes (123456 from Monday and 459459 from Friday) are different.
The goal of Availability is to ensure that data and services are available when needed and often addresses single points of failure. You can increase availability by adding fault tolerance and redundancies such as RAID, clustering, backups, and generators. HVAC systems also increase availability.
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