[openssl-users] EVP_DigestVerifyFinal with ECDSA signature

[Ken Goldman]

I'm trying to use the EVP interface for signature verification.

However, EVP_DigestVerifyFinal() takes a signature and length as 
parameters.  While I understand this for RSA, ECDSA signatures have R 
and S elements.

Is there a convertor function?

If I must convert by hand, how is it done?  In certificates, I see a 
0x04 followed by R and S arrays.