Creating a raw signature of a hex string

[James Muir]

On Sun., Apr. 23, 2023, 9:57 a.m. Robert Moskowitz, <rgm at htt-consult.com>
wrote:

> 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?
>

Here is a sign/verify example with Ed25519:

openssl genpkey -algorithm ED25519 -out ed25519-priv.pem
openssl pkeyutl -sign -rawin -in msg.txt -inkey ed25519-priv.pem -out
sig.raw
openssl pkeyutl -verify -rawin -in msg.txt -sigfile sig.raw -inkey ed25519
-priv.pem

I think you would need an extra step to convert your message from hex to
binary.

-James M

>
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