Secret communication

Introduced: September 1968

Of 7 combined children, 5 exist in both systems.

2 codes are CPC-only extensions.

Child Classifications

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H04K 1/003 CPC only CPC only
H04K 1/006 CPC only CPC only
H04K 1/02 by adding a second signal to make the desired signal unintelligible +1 CPC IPC+CPC Available in IPC and CPC
H04K 1/04 by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band IPC+CPC Available in IPC and CPC
H04K 1/06 by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards IPC+CPC Available in IPC and CPC
H04K 1/08 by varying the polarisation of transmitted waves IPC+CPC Available in IPC and CPC
H04K 1/10 by using two signals transmitted simultaneously or successively IPC+CPC Available in IPC and CPC