Who's There

Alejandro Sedeno, David McIlroy

HINTS:
SOLUTION:

This puzzle is in two parts, both of which are necessary.

The text that you see is a perl program after applying the vignere key "BENOISYREDHERRING" to all the letters.

Decrypt the perl program and it prints out WRONGWORD

The spacing is also important, because this puzzle is also written in whitespace.

Use the whitespace interpreter, and the program will appear to hang while waiting for input.

Type in WRONGWORD, and the interpreter will print out ILLUSION!, which is the correct answer.

Answer: ILLUSION