Tags: misc apl
Rating: 5.0
TUCTF 2018: APL
=============================
## Description
Dr. W gave me an old program of his... Can you tell me what it does? (Difficulty: Easy)
We get a text file APL.txt that contains:
```
mx←7 0↓14 9⍴⍳132
a←mx[(3 3)(3 4)(1 4)(3 3)(1 7)(7 6)(7 2)(3 1)(5 6)(3 3)(5 2)(4 5)(2 7)(6 2)(2 4)(7 4)(4 5)(2 1)(6 7)(4 5)(1 9)(4 7)(3 1)(5 1)(4 5)(3 3)(6 3)(4 5)(3 1)(5 2)(1 2)(5 1)(7 8)]
```
## Solution
After some research (and knowing the title of the challenge), we found out that this is a code interpretable in APL.
So we parsed the program on https://tryapl.org/. When we print the output of the variable `a` we got:
`84 85 67 84 70 123 119 82 105 84 101 95 79 110 76 121 95 73 115 95 72 97 82 100 95 84 111 95 82 101 65 100 125`
It looks like the flag in ASCII, when converting we retreived:
`TUCTF{wRiTe_OnLy_Is_HaRd_To_ReAd}`
