IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Organisation Remarks
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quality, all of the equipment along a transmission path has to be examined
and assessed. Although looking at a single component in isolation should
not be considered justified on account of the coupling of all relevant
individual effects, it is nevertheless important to be aware of the
influencing factors applying to each component (such as the crypto
component). The basic conditions for both implementation and selection
can be derived from this knowledge. The behaviour of an encryption
component is mainly characterised by the following factors:
- The period of time elapsing during encryption of a data block
(generally results in delays)
- The control information inserted additionally into the data stream for
synchronisation purposes (may result in fluctuations)
- The maximum data throughput to be achieved by the crypto
component (also results in fluctuations if buffer storage is necessary)
- The error propagation resulting from encryption (generally results in
an increase in the error rate)
In the case of voice encryption (real-time service), in particular, the above
influencing factors have a negative effect in the form of an increase in endto-end
propagation time, fluctuations in propagation time and a higher
error rate, i.e. in a reduction in quality which can be measured and can be
attributed to the crypto component.
- Other influencing factors
Some cryptographic algorithms (such as IDEA) are patented; licence fees
may have to be paid to enable them to be used in commercial applications
(to which the field of government agencies etc. also belongs). This must be
noted in particular when using methods such as PGP, of which there are
also implementations which can otherwise be used as public domain
software.
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IT-Baseline Protection Manual: Oktober 2000