Hello. I've done a similar job (see https://www.freelancer.com/projects/PHP-Engineering/Desenvolver-Software.5847276.html ) in the past and I think I can be of help to you.
On that one there was only a base64 encoding, but yours also got some C encoding done, which is the reason I'm rising my price.
Your provided .so file is built for a 32 bit system and dynamically linked so it's harder to decode. Can you provide a 64 bit statically compiled one? Or maybe better: the source!