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Tag: Factorization

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Factorization

Related:
#Number Theory
#RSA

Factorization is the process of expressing a number or expression as a product of simpler factors. This often means breaking a polynomial into lower-degree polynomials.

In cryptography, integer factorization is important because the security of some systems depends on how hard it is to factor large numbers. (automatically translated from Japanese)

minaminao
·Updated Apr 24, 2026
Factorization Challenges
a fact of CTF
xornet

xornet

Crypto
934 solves
RSA2026
theoremoon

theoremoon

Crypto
219 solves
Small N
pppp4649

pppp4649

Crypto
120 solves
42
minaminao

minaminao

Crypto
60 solves
Anti-Fermat
ptr-yudai

ptr-yudai

Crypto
31 solves
easy_factoring

mitsu

Crypto
29 solves
42*
minaminao

minaminao

Crypto
18 solves

42*

SECCON CTF 13 決勝観戦CTF
18 solves
Crypto

by

minaminao

minaminao

出力からフラグを復元してください🐍

import os
import random
from Crypto.Util.number import bytes_to_long

x = bytes_to_long(os.getenv("FLAG").encode())
for _ in range(42):
    x *= random.getrandbits(42)
print(x)

出力:

302825260919317779466638288706941757478119936504864503289299111810878557424069832851837952929397907929396668240458993245662741522591539210493306557224673507192171095532552008396687356525313836501117714017702880902013061423179550493813470620956236263763510927657899587551000326509836294794948423351121777067521675908878203343378571238778872260377769563951765315203164771192344115744888944635103673374760547507150197387248980588584664707496184797486345139870127142403853041203948936595396757260050089360185668376949219377211437731767603055237909466371770346897408000000000000000
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