How to issue electronic signatures?

Question

Law in IT

Colleagues, good afternoon. There was a need to electronically sign contracts with individuals from taxi companies when renting a car. So that in the event of an accident it was possible to prove in court that the car was with the tenant.

Does anyone have experience with electronic signatures? I see the procedure like this - the tenant uploads a passport photo, enters the code from SMS on the phone, after that we issue him an electronic signature, and one of the companies following the link should certify it? In what direction would you advise to dig? Using third-party services to issue e-signatures is not an option, everything should be in our system...

https://e-trust.gosuslugi.ru/#/portal/accreditatio...

UPD: You need something at the level of carsharing, there, after downloading the passport and the code from SMS, you can confirm in court that the car was on a person during the accident

Answer 1

everything should be in our system

Why would a client trust you with the private key of its certificate?
A client on your site binds its public certificate to its account. You verify that the signature belongs to him by signing a random block on the client side and verifying the signature on your side. You then store the certificate with you and use it to validate the client's signature.
In which of the CAs the client generated his signature should not concern you. The main thing is that the public certificate transferred to you is valid, that is, it has not expired and the signature chain can be traced to one of the root CAs that you recognize.