Project Sekai - ✅-crypto-bulbeuler

Project Sekai

🔒 UMDCTF 2023 / ✅-crypto-bulbeuler

Bulbeuler - 500 points

Category: Crypto Description: Bulbasaur told me they are the next Euler Author: gary Files:

Tags: No tags.

Sutx pinned a message to this channel. 04/28/2023 7:59 PM

@unpickled admin bot wants to collaborate

@sahuang this one might just be a fermat problem lmao

20:32

kinda skimmed but

im doing it

20:33

looks ez

ye

20:39

ye so g^(x+y) = 1 mod p if and only if the bit is 1 (edited)

20:40

i think i can solve from here

20:40

holdon

im doing the same thing somehow didnt get flag

20:41

weird

@fleming wants to collaborate

UMDCTF{I_d0nt_th1nk_bulby_!s_th3_n3xt_3ul3r_tbh}

20:44

idk

20:44

worked for me

send script

20:44

wtf

did it in console so hold on lemme clean this up

oo sure

20:45

you can submit

20:45

on ur accnt

p = 6596997572802685744626960256235787019476434707654191935397530271983648431547
d = open("output (36).txt").read()
d = d.split("\n")
d.pop(0)
d.pop(-1)
flag = ""
for x in d:
    gx, gy = x.split(", ")
    gx, gy = int(gx), int(gy)
    if (gx*gy)%p == 1:
        flag += "1"
    else:
        flag += "0"
flag = int(flag,2)
from Crypto.Util.number import long_to_bytes as l2b
print(l2b(flag))

20:47

(for me its output (36) i really need to use folders)

oh

20:48

output is g^x and g^y

20:48

already

20:48

yeah i see what i did wrong

20:48

i thought its x and y and do sth like g^x again lmao

https://discord.com/channels/919744111391698945/1101384675206893598/1101690167762358373 owait this is awkward

20:49

i submitted on my acc

20:49

uh

20:49

lmao ok this is fine prob

20:49

eh

whats the issue

20:49

yeah

oh was i supposed to?

its prob better to submit on ur account

20:49

yeah

ohh

submit on bot is also fine but better to use personal accnt

ok imma go back to afking because idk ~~i think im using ctf to get out of hw, prob not the best idea~~

loool

20:50

do /ctf solve then

unpickled admin bot

used /ctf solve

✅ Challenge solved.

Exported 46 message(s)