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DIFF Main Group
H04K 1/00

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 1/04 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

Top Applicants

Top Applicants (IPC)

Class H04,2013–2023, worldwide · Source: EPO PATSTAT

  1. QUALCOMM US 97,396
  2. HUAWEI TECHNOLOGIES COMPANY CN 96,502
  3. SAMSUNG ELECTRONICS COMPANY KR 86,981
  4. TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) SE 55,869
  5. HUAWEI TECHNOLOGIES COMPANY 55,349
  6. LG ELECTRONICS KR 53,649
  7. CANON 33,341
  8. SONY CORPORATION JP 32,761
  9. ZTE CORPORATION CN 32,274
  10. GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORPORATION 28,327

Top Applicants (CPC)

Class H04,2013–2023, worldwide · Source: EPO PATSTAT

  1. HUAWEI TECHNOLOGIES COMPANY CN 101,476
  2. QUALCOMM US 101,139
  3. SAMSUNG ELECTRONICS COMPANY KR 96,655
  4. TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) SE 57,744
  5. LG ELECTRONICS KR 55,253
  6. HUAWEI TECHNOLOGIES COMPANY 54,181
  7. SONY CORPORATION JP 35,309
  8. ZTE CORPORATION CN 32,950
  9. INTEL CORPORATION US 27,533
  10. GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORPORATION CN 27,498