"I doubt SETI could detect even our own signals, when it’s encrypted digital data. I mean it’s just noise like any background signal" Just because it's "noise"

"I doubt SETI could detect even our own signals, when it’s encrypted digital data. I mean it’s just noise like any background signal" Just because it's "noise" (ie. random/unpredictable looking) doesn't mean it's indistinguishable from other "noise". Not all "noise" is created equal. "noise" can have properties that make it distinguishable from other "noise". You may have heard of "white noise", "brown noise", "pink noise", "gaussian noise", etc... A sequence that appears random or unpredictable may nevertheless fall in to certain distributions. I am not an astronomer, statistician or cryptographer, but would not be in the least surprised if encrypted communication could be clearly distinguishable from the cosmic microwave background radiation -- not only based on its distribution, but other properties such as intensity of the signal, how frequently the signal appears, and other much more advanced signal analysis techniques which are way beyond my expertise to analyze but not beyond the experts at SETI.