1.1 Talking security: the basics
This section is part of the amber and green pathways.
In any discussion of security, there are some basic terms that will be used a lot. This section will introduce you to the basic terminology of information security.
The guiding principles behind information security are summed up in the acronym CIA (and we’re pretty sure there’s a joke in there somewhere), standing for confidentiality, integrity and availability.
We want our information to:
- be read by only the right people (confidentiality)
- only be changed by authorised people or processes (integrity)
- be available to read and use whenever we want (availability).
Often, these properties are represented as a ‘triad’ (see Figure 2).
It is important to be able to distinguish between these three aspects of security. So let’s look at an example.
Case study: PlayStation Network
In April 2011, Sony revealed that the PlayStation Network, used by millions of consumers worldwide, had been breached by hackers. The breach went unnoticed by Sony for several days and ultimately resulted in the theft of up to 70 million customer records. The records included customer names, addresses, emails, dates of birth and account password details. This is information which could have enabled additional attacks or identity theft.
In order to assess the scale of the damage and repair the vulnerabilities that led to the attack, Sony took the PlayStation Network offline, a move which cost the company, and merchants who offered services via the network, significant amounts of revenue.
In addition to the cost of fixing the breach, Sony was fined £250,000 by the Information Commissioner’s Office as a result of a ‘serious breach’ of the Data Protection Act, stating that ‘The case is one of the most serious ever reported to us. It directly affected a huge number of consumers, and at the very least put them at risk of identity theft.’
The precise financial cost to Sony is unclear but estimates place it at approximately £105 million, excluding the revenue loss by partner companies, damage to its reputation and potential damage to its customers.
So how do the principles of CIA apply to the PlayStation case? Quite obviously, confidentiality was violated: unauthorised people could read the data. However, authorised users still had full access to the data, so it remained available; and the data was not changed, so its integrity was preserved.
Time for another definition. When talking about valuable data we use the term ‘information assets’. In the PlayStation case, the information assets were the data about Sony’s customers.
When we consider security of online communications and services, we also need two additional concepts: ‘authentication’ and ‘non-repudiation’.
When we receive a message, we want to be confident that it really came from the person we think it came from. Similarly, before an online service allows a user to access their data, it is necessary to verify the identity of the user. This is known as authentication.
Non-repudiation is about ensuring that users cannot deny knowledge of sending a message or performing some online activity at some later point in time. For example, in an online banking system the user cannot be allowed to claim that they didn’t send a payment to a recipient after the bank has transferred the funds to the recipient’s account.
Figure 3 illustrates the role of authentication and non-repudiation in the context of security; they form the basis for achieving the security goals