usernameFragment property on the
RTCIceCandidate interface is a string indicating the username fragment ("ufrag") that uniquely identifies a single ICE interaction session.
This value is specified when creating the
RTCIceCandidate by setting the corresponding
usernameFragment value in the
RTCIceCandidateInit object when creating a new candidate with
If you instead call
RTCIceCandidate() with a string parameter containing the
candidate m-line text, the value of
usernameFragment is extracted from the m-line.
var ufrag = RTCIceCandidate.usernameFragment;
DOMString containing the username fragment (usually referred to in shorthand as "ufrag" or "ice-ufrag") that, along with the ICE password ("ice-pwd"), uniquely identifies a single ongoing ICE interaction. The string may be up to 256 characters long, and has no default value.
At least 24 bits of the text in the
ufrag are required to be randomly selected by the ICE layer at the beginning of the ICE session. The specifics for which bits are random and what the remainder of the
ufrag text are are left up to the browser implementation to decide. For example, a browser might choose to always use a 24-character
ufrag in which bit 4 of each character is randomly selected between 0 and 1. Another example: it might take a user-defined string and append three 8-bit random bytes to the end. Or perhaps every character is entirely random.
ICE uses the
ufrag and password to ensure message integrity. This avoids crosstalk among multiple ongoing ICE sessions, but, more importantly, helps secure ICE transactions (and all of WebRTC by extension) against attacks that might try to inject themselves into an ICE exchange.
Note: There is no API to obtain the ICE password, for what should be fairly obvious security reasons.
ufrag string remains consistent across multiple generations of the same ICE process, even across ICE restarts.
|WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'RTCIceCandidate.usernameFragment' in that specification.
|Candidate Recommendation||Initial definition.|