In many countries use of cryptographic techniques across public communications resources is prohibited by law. In such cases it is normally permitted to use cryptograpy provided the message may be read as plaintext by the authorities.
A means of keeping within the law is the use of mandated keys. A mandated key is one which must be carried by all communications within a particular sphere. The secret component of such a key is held in escrow by the mandating authority. To ensure that manadated keys do not provide a security threat a mandating authority must provide a sufficiently large number of keys.
Phillip M. Hallam-Baker CERN Programming Techniques Group hallam@alws.cern.ch Version 1.0R1