Encryption in Data Networks with Application to Teletex

TELETEX is a new international telecommunication service for text communication between terminals capable of data storage and possibly integrated in a information processing system, [l]. The new service is intended to fill the same needs as does business mail. With regard to information security this means that the information handled by the TELETEX system shall not be unintentionally changed or destroyed or lost to an unintended receiver. Measures to prevent this are called information protection. (We prefer to use the terms information security and information protection rather than data security and data protection. The reason is that "data " in the sense of a string of symbol s may be lost without revealing the information represented by the data. This is for example the case when the data consists of encrypted information). One of the most efficient methods for information protection is to use encryption. This means that the information is transmitted using a ''language" which i s not understood by is efficiently protected against loss and in most cases also against undetected change. Cryptological methods can also be used to detect information destruction. In Section 2 of this report we discuss the basic problems involved with the use of encryption in data networks in general. In a separate report we discuss the possible threats to the information security in TELETEX. This leads to suggestions regarding suitable protection methods. Our standpoint is that TELETEX shall offer at least the same level of information security as does the established mail distribution system.