Among all the CTF puzzles, i am clueless of this one. Below is the function part of code. You use the input function to type in the string and verify_password will validate the string to see if it is the correct password. I try to follow the verify_password function to understand its logic for hours. What is the proper way to solve this kind of problem? Thanks for any input!
import builtins
def input(a,*b):
p=builtins.input(a)
return "".join([p[i:i+7][::-1] for i in builtins.range(0,len(p),7)])
def system(a):
import urllib.request, time, random
for i in urllib.request.urlopen("https://problems.metactf.com/content/perplexing_python/rmrf.txt"):
if random.random()>0.99:time.sleep(random.uniform(0,1))
if random.random()>0.9:time.sleep(random.uniform(0,0.2))
print(i.decode().strip())
def triangulars(x):
o=[]
for i in builtins.range(2,x):
for j in builtins.range(2,round(i**0.5)+1):
if i%j == 0: break
else: o.append(i)
return o
def verify_password(pwd):
from functools import reduce
pwd=[ord(i)^len(pwd) for i in pwd]
with open(__file__, "r") as f:d=f.read()
pwd=[pwd[i]^ord(d[i*3]) for i in builtins.range(len(pwd))]
n = 0
t = [i for i in triangulars(1000) if i > 256]
p = 1
for i in builtins.range(len(pwd)):
n += pwd[i]*p
p *= t[i]
crt = [[893291192969389,321083022148697],
[738075405357203,535606301382888],
[111116004743251439,85887918631122595],
[189984495189322679,105666774352769436],
[657759577575876253,576519854972390374],
[534767534514091169,151381645215045547],
[5802402697964251471,1097309430872784120],
[10313116996519561687,3795752970155700631],
[5280231861548814769,3904915951384167352]]
return all([n%i[0]==i[1] for i in crt])
def range(*a): return [2, 1, 0]
