Tags: crypto recursive
Rating:
``` python3
from out import enc, R
from math import prod
flag = ''
# a is a long array that goes by
# First iteration: [0, 1, 2]
# Second iteration: [0, 1, 2, 1, 2, 3, 2, 3, 4]
# It goes on...
# As you can see, the length of a is in the multiple of 3s and each "subsection" starts off from its index in the subsection increments e.g. 1, 2, 3, 4..
# This can be solved with a simple recursion function
def recur(r):
if r // 3 == 0:
return r % 3
return recur(r // 3) + r % 3
for i in range(len(enc)):
flag += chr(enc[i] ^ prod([recur(_) for _ in R[i]]))
print(flag)
```
