Generating and checking SM2 signatures

[Jörg Heßdörfer]

Hello,

I'm tasked to implement certain cryptographic functions (chiefly 
signature creation/validation) using the SM2 algorithm for a 
communication testing application. My problem is that the standard which 
I need to follow (which is, unfortunately, not a public standard) states 
that the signature needs to be generated over H(data input) || H(some 
ID) , so I cannot use the EVP-Method as I understand it from 
https://www.openssl.org/docs/manmaster/man7/SM2.html (here, H is the SM3 
hash function). This would be possible to achieve by generating the 
digest and then using the (albeit deprecated) function ECDSA_do_sign for 
ECDSA but I don't know how to do it for SM2.

Is there any way to do this with openssl? Any help or pointer is very 
much appreciated!

Thank you,

     Jörg

-- 
Jörg Heßdörfer
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