To quote MSDN:
"Gets or sets a Boolean value that indicates whether User ID and Password are specified in the connection (when false) or whether the current Windows account credentials are used for authentication (when true)." (
MSDN[
^])
That's from the .NET SqlConnection class property of the same name, but it describes exactly what the Connection string option is and does: it's a bool which tells SQL Server is authentication details are provided in the connection data.
So yes,
true
and
false
are the only valid values.