Subject: [rtcweb] Moving Identity tokens between contexts

From: Harald Alvestrand <[email-masked]>
Date: Thu, 3 May 2018 13:58:56 +0200

To make sure we're all on the same page:

The identity token is a JSON blob - ie a string.
There's absolutely no way to prevent the page from passing it to anyone
it wants to pass it to - and there shouldn't be.

In contrast, the RTCCertificate is an object with an interface that has
a specific guarantee:

"No mechanism is provided for applications to access the
[[KeyingMaterial]] internal slot."

and therefore this further statement can be made to implementors:

"In implementations where an RTCCertificate might not directly hold
private keying material (it might be stored in a secure module), a
reference to the private key can be held in the [[KeyingMaterial]]
internal slot, allowing the private key to be stored and used."

I think it doesn't make sense to move such an object between origins. We
might want to state that explictly. (But that's a W3C issue, so ought to
be addressed to a different list.)