Creating a raw signature of a hex string

[Robert Moskowitz]

This is for work in the IETF DRIP workgroup and the objects created in

https://datatracker.ietf.org/doc/draft-ietf-drip-auth/

and used in

https://datatracker.ietf.org/doc/draft-moskowitz-drip-a2x-adhoc-session/

I have a 136 byte object:

2e4a3f5b5e07a1fb254b811f5a1002b10a5fda326d944758324d7f16972aa2f63c4722b92001003ffe001405

And a pem formatted private key file (EdDSA25519) file.

I want the 64 byte signature.

So far in all my googling I have only found:

https://stackoverflow.com/questions/35443847/how-to-create-detached-cms-signature

and

openssl cms -sign -signer cert.pem -inkey pkey.pem -binary -in data 
-outform der -out signature

I think I would cut out the -signer, as no cert, just the pkey.

This is NOT cms, no way, but is that needed.

Basically what do I need to sign a bunch of bytes and get the signature?

thanks