1. General information and basic concepts

1.1 Security, a requirement for information

There are many threats to organizations, whatever their type of activity. The more sophisticated the technology, the higher the probability of a threat, and the more difficult it is to detect. Threat sources are highly varied: computer fraud, espionage, sabotage, unauthorized access, identity theft, site attacks, viruses, Trojans, vandalism, fire, flood, equipment failure, denial of service, data theft...

All these vulnerabilities, with their host of harmful consequences, engender fear, because they can lead to dramatic situations,...