Is it possible to parse NCA RK EDS keys without using NCALayer for integration with state portals?

Question

Electronic digital signature

It is necessary to parse the NCA RK EDS keys on the client side: AUTH, RSA, GOST, without using third-party programs such as NCALayer, etc. for signing documents and sending them to the server of state portals using the API.
Tell me if this is possible, where to find literature, in what direction to move, etc.?
Has anyone implemented something like this?

Thank you in advance.