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Information has a natural lifecycle, but as with most things in the IT world, there are many different models for this lifecycle, with different emphasis placed on different phases of the data's existence. For example, ISO 27002 defines this cycle with five phases: creation, processing, storage, transmission, and deletion/destruction (see Figure 1.2). Other models, such as those built into many systems management platforms such as SAP, may combine creation and use with processing; then add a retention phase in which the data is not actively used but cannot be disposed of because of legal, regulatory, or liability reasons; and finally end with a disposal and destruction activity.

FIGURE 1.2 ISO 27002 phases

Security is an important consideration at every phase, but the level of importance can vary, depending on the phase. The formats and media used in the various phases can also affect the security considerations.

Consider, for example, design documents for a new product or technology. When those documents/data are new, they are valuable and actionable, especially if a competitor acquires them. Once the product or technology is in production and is being sold on the market, those same documents could be near the end of their lifecycle. At this point, one could argue that the documents would do less damage in the hands of a competitor, but they still need to be afforded some level of protection, right up to the moment they are destroyed. In this example, even though the creators have benefited from the “rush to market” advantage, the design documents themselves could still contain sensitive data, such as a proprietary production method, which the organization plans to reuse in future products.

There are several important points to take from this example. First, the security impact may vary depending on where the information is in its lifecycle. Next, even though the impact may vary, there can be negative outcomes for the organization at any phase. Finally, phase five, the deletion and destruction phase, is important because destruction of unneeded assets reduces the organization's attack surface. Data at the end of its lifecycle only introduces risk, with little to no benefit.

The lifecycle view shows that datasets (or information assets) are constantly going back and forth from storage to use; throughout that ever-repeating cycle, your systems designs should protect the information while it is at rest, in use, and in motion. Currently, well-chosen encryption systems can protect data in motion and at rest and by means of digital signatures offer the stored copies protection in time as well. (Chapter 5 goes into this in further detail.) However, thus far there are not many solutions to protect data while it is being used from compromise or loss, since most operations on data and its use by humans needs to have the meaning of the data readily available.