No, I think it's solvable and even easy (depending on definition). Beforing you gave the tips I saw that "scrambled" trimmed the response always at the same byte length. Then I saw everytime it returned something different. Then, doing a "for i in $(seq 0 50); do curl izhack.com:12345 | head -7 | tail -1 | cut -c 1-250; done; I could see the pattern.

Doing the same for the other lines, replacing head -7 with head -8, head -9, etc I grabbed the repetition columns for all 5 lines. Each line had different columns repeated.

Creating a 5x300 grid and marking the cells where repetition occurs you see there's a symmetry. The repeats 5 times, where at column 58 every line repeats and it marks the repetition.

This is where I left, I still don't know the meaning of the last line. When I first run, coincidentally the server returned "sAlt" :-)

I was only asking if you knew the book because you seem to like puzzles and me too. As I liked the book I thought you might like and was trying to start a conversation.

Sorry!