This is an nginx http module.

ngx_http_virtualssl provides an alternative SSL SNI servername callback handler.
This module requires an additional patch to actually work.
ngx_http_hs MUST be loaded and configured.

Example configuration:

http {
    hs_route_db /home/ch/cloud.tcb;
    hs_key_material_db /home/ch/keymat.tcb;
    server {
	/* standard ssl configuration */
	virtualssl on;
    }
}