Presumably this could be done transparently by the web server? Incoming cookies could be validated and then the underlying cookie value passed on to the app. Me

Presumably this could be done transparently by the web server? Incoming cookies could be validated and then the underlying cookie value passed on to the app. Meanwhile, cookies set by the app get rewritten by the web server to include the signature. This would mean that no server-side code would need to be changed in order to support the cookie signing. Are there any web servers out there that do this?