I know that the majority of people use standardized encryption ciphers such as AES-256, and for good reason. But what I want to know is if anyone has come across a company or organization that is selling their own proprietary symmetric encryption algorithm. I'm doing research on this specific use case and would appreciate some help.

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    $\begingroup$ Several countries have their own crypto algorithms (China, Japan, Russia, Korea etc.). There should be a few classified ciphers as well by various intelligence agencies or military organizations. I have the feeling that proprietary block ciphers are on the decline in commercial organizations, although some are of course still in use in legacy products - especially embedded products. MIFARE anyone? $\endgroup$
    – Maarten Bodewes
    Jul 17, 2019 at 22:47
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    $\begingroup$ There are actually many companies that develop and sell proprietary algorithms, the Rijndael developers I believe worked for one and developed proprietary algorithms, and used that experience to perfect the design of what is now AES $\endgroup$ Jul 17, 2019 at 23:50
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    $\begingroup$ You might also want to look into VPNs, those often apply proprietary (and tbh therefore dubious) protocols. $\endgroup$
    – tylo
    Jul 18, 2019 at 0:42
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    $\begingroup$ cyber-crypt.com recently developed a trinary hash function for the IOTA blockchain $\endgroup$
    – Ruggero
    Jul 18, 2019 at 7:22
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    $\begingroup$ A... what hash function? $\endgroup$
    – forest
    Jul 18, 2019 at 7:30

1 Answer 1


Yes. One prominent commercial example is Cypto AG, a company in switzerland. Its clients include some nation states. Of course most major nation states have their own proprietary diplomatic and military symmetric key algorithms.

See the Crypto AG website here.

Historically, they have been involved in some controversies. See one example report here.

Googling will yield much more on Crypto AG and its history, usual caveats apply. The main objection is lack of open peer review.

Edit: References to Crypto AG's proprietary algorithms are given below. I am not claiming these are secure algorithms, FWIW.

The link here has a company document from 2007:

"For encryption, the proprietary HCA-480 crypto algorithm is used in combination with Customer Managed Profiling (CMP), offering a variety of over 10506. The Communication Key (CK) is 128 bits long and is used to generate a key stream with a period of more than 1028 years."

A newer link is here:

"All systems are based on the sophisticated Crypto Security Architecture, which comprises elements such as a tamper-proof hardware module, customer-controlled and proprietary algorithm [..] emanation-proof hardware (COMPREM) and a flexible security and network management."

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    $\begingroup$ Among their products is claimed a post quantum safe symmetric algorithm. - That makes it sound like snakeoil to the extreme. Symmetric algorithms are naturally quantum-resistant. $\endgroup$
    – forest
    Jul 18, 2019 at 0:56
  • $\begingroup$ I've just checked their website and it appears they are not advertising a post-quantum safe symmetric product, but stating that they use AES and that AES, like other symmetric algorithms, is not particularly affected by quantum computers. Although their site absolutely gives off red flags, I retract my snakeoil comment. $\endgroup$
    – forest
    Jul 18, 2019 at 1:53
  • $\begingroup$ @forest I agree. That site really does raise red flags, but the biggest of all is simply that the founder, Boris Hagelin, "...had helped supply the US Army during the War (WW II) before moving his business from Sweden to Switzerland." And his BFF was William F. Friedman--of Puzzle Palace fame. $\endgroup$
    – Patriot
    Jul 18, 2019 at 7:05
  • $\begingroup$ I think Crypto AG may well still sell crypto products with backdoors and the comments are all spot on. The answer, as is, is still valid to the OPs question. $\endgroup$
    – kodlu
    Jul 18, 2019 at 7:44

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