At some point, someone will just brute-force these.
Another is probably written in an invented, private language.
Two others are short enough that brute force approaches will almost certainly create false positives.
In general, brute force can only work if you have some idea of what to expect the clear text to look like.
So what if false positives are created? We can just brute-force the analysis of those to find the right one. Are you forgetting the sheer magnitude of quantum, digital, & human-analog computing power we have available today?
Given the folks who've attacked these problems, the ones that have yielded to brute force thus far: 0.
You're going to have to quantify "smartly" into something more objective before you can use it in this argument.
Where else do we have 2 mixed streams of information? Music. Optics. So we take the input and reverse the mod26, one step at a time, basically creating an array of "demodulated" input values, then I feel as though we should be able to do a Fourier analysis to separate the 2 strings of numbers.
So when you say "cipher", that means you want every possible algorithm. Since algorithms can produce output shorter than the input, you get the infinite amount of inputs.
With one-time pads, fourier analysis would only work if the key is not truly random.
How do you reverse a "mod26"? You can't. I give you the number 17. You know this number is produced using the equation: "SECRET mod 26 = 17". How do you know if 43 or 69 was the input?
What am I missing here?
How many billions of NTLM keys can a Geforce crack in a second? How is this cryptography problem so greatly different than that one?
According to https://hashcat.net/oclhashcat-plus/ , it's approximately 2.5 B.
This corresponds to a one time pad message of just under 4 bytes long. The difference, of course, with NTLM is you know when you've found the right value. With OTPs, all decryptions are possible and equally valid.