Defense in Depth is the concept of protecting a company's data with a series of defensive layers so that if one layer fails, another layer will already be in place to thwart an attack. We start with our data, then we encrypt it to protect it:
- The data is stored on a server
- The data has file permissions
- The data is encrypted
- The data is in a secure area of the building
- There is a security guard at the building entrance checking identification
- There is CCTV on the perimeter
- There is a high fence on the perimeter
Therefore, before someone can steal the data, they have seven layers of security that they must pass through. The concept of defense in depth is that if one layer fails, then the next layer protects: