IPC Main Group
H04K 1/00 Secret communication
Introduced: September 1968
Last revised: January 2006
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRIC COMMUNICATION TECHNIQUE
- Subclass:
- SECRET COMMUNICATION; JAMMING OF COMMUNICATION
5 direct subcodes
Child Classifications
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- H04K 1/02 by adding a second signal to make the desired signal unintelligible
- H04K 1/04 by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band
- H04K 1/06 by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards
- H04K 1/08 by varying the polarisation of transmitted waves
- H04K 1/1 by using two signals transmitted simultaneously or successively