How to access the EDS service through a browser?

Question

Browsers

Let's say we have a website. Every message or document on this site is signed when sent. The user has a digital signature and key storage service installed on the machine. The user writes a message in the browser, before sending the site asks the browser to sign the message, the browser asks for a service. With this scheme, the service is responsible for security, confidentiality, and all secret operations take place locally.
Has such a mechanism been implemented? What is the other (better, easier)?

Answer 1

From the CMS, look at Bitrix in Site Management 11, there is an EDS login and signing. Other CMS exist, but I don't know where to scratch them out.
https://habrahabr.ru/post/142625/ this article describes how to work with such cryptography.
By the way, the SDK is available for free (after registration), this is one of the easiest solutions: www.cryptopro.ru/products/cades/plugin