[Galene] Re: coturn config

[Juliusz Chroboczek <jch@irif.fr>]

>>             "username": "galene",
>>             "credential": "secret",
>>             "credentialType": "hmac-sha1"

> There is no username in the coturn configuration when using TURN REST API,
> so is the "username" key still necessary here?

It is optional.  If present, it will be communicated to the TURN server in
a secure manner (it cannot be spoofed by the client), so it may be used
for logging or accounting.

The protocol is fairly simple.  The WebRTC server picks an expiration date
for the credentials and encodes it as Unix time in base 10.  It then sets

   if original_username == ""
      username = expires
   else
      username = expires:original_username

   password = BASE64(HMAC_SHA1(username, secret))

This is equivalent to the code that Toke posted earlier, except that that
code picks the username at random.

-- Juliusz