C# (.NET Core), 130 152 bytes, CRACKED
+22 bytes, I forgot about trailing newline... Program works the same as before, the newline is added to any output.
a=>a.Distinct().Select((x,y)=>a.Reverse().Skip(y).First()*x%255).Take(a.First()-33).Concat(new int[]{10}).Select(x=>(char)x).ToArray()
Byte count also includes
using System.Linq;
For a start I went for something not too crazy. It can has multiple answers.
The "official" crack:
. !$0%>5&8'#?)S*TuE[MRX`+9