Year
1989
Abstract
To protect a security instrument such as a television camera from subversion by signal substitution, the data from the instrument are digitized and submitted to an authenticator. The digital data may then be transmitted in the clear over a nonsecure medium. Appended to the data is a 10-bit authentication value based on the values of the data and a random authentication number. At the receiving end, the data are submitted to an identical authenticator. If it produces the same authentication value, the data are authentic. Such a scheme can work only if the instrument, the authenticator, and the link between them can be protected from tampering. This paper describes a tamper resistant container designed to protect a data authenticator and television camera against an adversary having sophisticated resources and complete design information. The container's design includes active elements to detect and report intrusion attempts in real time. It also includes passive elements to indicate upon later inspection whether the container had been violated.