Data at rest
The inactive data which is physically stored in databases, spreadsheets, data warehouses, mobile devices and the like, can be referred to as ‘data at rest’ for example data residing in hospital database. The loss of such data might result in embarrassment, discrimination in the workplace or even the threat of physical danger for the persons concerned. From an information security viewpoint, data at rest is vulnerable and needs to be protected.
Public sector organisations should take the utmost care that sensitive data such as personal records is protected against brute force attacks with strong encryption for when basic authentication methods like username plus password fails.
Data in transit
Data which is transferred between two nodes in a network is ‘data in transit’. Examples of sensitive public sector data in transit might include confidential emails or video messages being transmitted from one computer to another, which could divulge government secrets; tax returns sent electronically which could result in theft; or even missile codes being sent from HQ to a nuclear submarine.
As a rule of thumb, organisations should assume that the network cannot be trusted. Consequently, all sensitive data must be protected with network encryption, supplemented by supplemented by SSL certificates, Internet Protocol Security (IPSec) and other precautions where relevant.
Data in use
We can use the term ‘data in use’ to refer to that data which is being used in an in-memory state. Google Chrome, for example, loads up websites in-memory that it thinks you might like to look at next so that it operates more quickly. Government employees might keep classified web pages in-memory while browsing. Sensitive ‘data in use’ needs to be protected by application-level encryption and exposed on a need to know basis, encrypted as soon as possible and decrypted only when necessary. Such a selective approach to encryption can only be performed at the application level.