On the Meaning of Safety and Security

The terms 'safety' and 'security' are often used to characterise computer systems when used in a context where reliance is placed upon them. These terms are normally regarded as representing distinct properties, yet there is considerable ambiguity in the terms. At a linguistic level, the common phrase 'safe and secure' indicates a limited distinction and, in Germanf, no real distinction can be made as the term sicherheit means both safety and security (although some technical terminology has been introduced to make distinctions between the two notions). Further, in many dictionaries, safety is denned in terms of security and vice versa. There are also some difficulties in practice in deciding when to use which term. For example, the following problems might be treated as problems of safety or security (or both):