It is true that Web Real-Time Communications (WebRTC) is encrypted, but additional security measures are still...
Without some third-party identity service or certificate authority, however, WebRTC media flows are vulnerable against attacks like a man-in-the-middle (MitM) attack, where an intruder intercepts communication between a user and a website. For example, ZRTP: Media Path Key Agreement for Unicast Secure RTP provides protection against MitM attackers using key continuity augmented with a Short Authentication String, in which two users verify that there is no MitM by verbally comparing two strings. An IETF memo describes how ZRTP can be used over the WebRTC data channel to provide MitM protection for WebRTC media flows keyed using DTLS-SRTP. This provides users protection against MitM attackers without requiring browsers to support ZRTP or requiring users to download a plugin or extension to implement ZRTP.
Further, I would argue that security should be applied to any source that contains embedded code to further guard against denial-of-service attacks and other attacks that could make the transmission unavailable. As with all things Internet, you have to secure transmissions of any kind to protect them from vulnerabilities.
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