Armv8.4-A will add extended support for more cryptographic primitives, to include SM3, which is a cryptographic hash function used in the Chinese National Standard; and SM4, a 128-bit block cipher; along with SHA2-512 and SHA3. 1

I am just curious as to why Armv8.4-A added support for SM3 and SM4? It's odd, especially since SHA3 is slightly more secure than SM3 (in collision attacks, but SM3 is more secure in distinguishing attacks). 2 The SM3 cryptographic hash function and AES offer better security than SM4. 3

Question: Is there any advantage in using SM3 or SM4 over NIST-approved algorithms?

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    $\begingroup$ Yes, possibly if you are Chinese. Basically, these kind of algorithms will only be added on request in my experience. For the rest of us it is a waste of transistors. $\endgroup$
    – Maarten Bodewes
    May 15, 2019 at 9:27
  • $\begingroup$ What is the main purpose of request ? Is there any particular reason? $\endgroup$
    – hardyrama
    May 15, 2019 at 14:25
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    $\begingroup$ Well, this was kind backwards reasoning. We thought to be nice and include it in a product spec, but basically they did not want it in. I don't know the details. These things you put in a product at request of a large Chinese company or governmental organization, I guess. Nobody else uses these country specific algorithms - unless you include the US, maybe :) I've even not seen practical use of the Camelia cipher. And I tested with a French curve - but only because my company was French. $\endgroup$
    – Maarten Bodewes
    May 15, 2019 at 14:31

1 Answer 1


If you are seeking a government contract with China, you might be required to use Chinese government standards for cryptography, just like if you are seeking a government contract with the United States, you might be required to use United States government standards for cryptography. There are many national pride cryptography standards that have little technical reason to recommend over widely used systems like BLAKE2, Ed25519, etc. Some of them become prominent enough to matter commercially.

  • $\begingroup$ just curiosity , could the deal by "SoftBank sells off more than half of Arm China for a bargain $775.2m" has influence on supporting cryptographic Chinese standards? I see it from business prospective. $\endgroup$
    – hardyrama
    May 20, 2019 at 18:36
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    $\begingroup$ I have no idea, and as an anti-capitalist pseudonymous bone-eating fowl on the internet, I am not competent to answer questions about SoftBank's business strategy. $\endgroup$ May 20, 2019 at 18:40

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