SETI will never report finding a real alien signal, and it cannot. Its not possible because assumes an artificial signal will repeat. That's exactly the opposite of what they should assume.
A good starting assumption is a "dark forest" scenario. Even if there aren't berserker aliens out there hunting down signals, any civilization will have its own bad actors. Thus, secure communications will be a priority for any technical society. If you repeat a signal, or worse, repeat certain elements of it, then that repetition makes it stand out for scrutiny. As a society develops its encryption, it will find certain patterns in the never ending arms race of encryption and cracking.
The origin of the artificial signal has to worry about three things : their location being known ; their message being cracked by bad guys ; and their message being readable by good guys. All other details have to conform to fit in that.
How to satisfy all conditions? You know those TOTP tokens you save for authenticating stuff online? Something like that. The algorithm underneath is a black box, and the output is unguessable in the few seconds its needed. This would hint that the security of an alien signal is proportional to the duration of the broadcast. But more importantly, a one way algorithm allows you to hop frequencies, divide parts across the spectrum, compress data, and then alter all of these characteristics randomly and still be readable to the good guys.
Or more simply : good encryption will look like background noise.
The signal will never repeat. In fact, repetition of a signal should be automatic disqualification for an intelligent origin.
And this is why I'm calling BS on that signal that SETI is looking at. Just my opinion.
