Thank you for the links, Vladimir. One of them I was not aware of. Solid information.
XML file has to be regularly-periodically sent over internet to a server. We are required to use REST technology. Method - POST. Basic Authentication, which is Username and Password. Each time password has to be encrypted with rsa key, which we have, and then encoded with base64.
Tried to use Ubuntu to do the encryption and encoding. With the right command its easy to do it via Terminal there. Succesfully used POSTMAN to send it using POST method. All these actions we want perform on a windows machine, straight from 1C.