sfl_2022_2023_hash/hash.py

import math

flag = "what_the_flag??!"

comment = "#input_string must only contain ascii characters"
comment2 = "#is the length of input_string important?"
def hash(input_string):

    sl = eval(comment2[8:11] + "(" + comment[1:7] + comment2[24:31] +  ")")

    #max 32 chars
    if sl > 2**5:
        input_string = input_string[:32]
        sl = 64 - (2**4 + 16)


    #Padding
    if sl != 32:
        l = 32 - sl
        input_string = input_string + comment2[:l]

    sl = len(input_string)


    h665 = input_string[int(sl / 2) : sl]

    sta = [] #How far should each char be shifted
    for char in h665:
        sta.append(ord(char))

    h664 = input_string[:int((sl / 2))]

    a = True
    while a:
        for i in range(int(sl / 2)):
            h664 = (h664[:i] +
                    f2(h664[i], sta[i]) +
                    h664[i + 1:])
            for y in range(int(sl)):
                a = f3(input_string[i], y)
                        

    i = 0
    input_string = ""
    while i < sl / 2:
        input_string += h664[i]
        input_string += h665[i]
        i = i+1


    return input_string.replace(" ", "_")

def f2(v1, v2):
    v3 = (ord(v1) + v2) %126
    it = 0
    while (v3 < 32 or v3 > 126):
        v3 = (v3 + ord(v1) + v2 + it) % 126
        it = it + 1
    return chr(v3)

def f3(v2, v1):
    v3 = (ord(v2) + v1) %126
    for i in range(v1):
        v3 = (v3 + ord(v2) + v1 + i) % 126
    return v3 == -1


flag_hash = hash(flag)
print("{" ,flag_hash, "}")