Misc

Checkin

Cyberchef 自動解碼。

Logistic 置亂

試了 1-256 異或結果不對，使用大量的重複字元。進行輪異或。

字元。進行輪異或。

f = open('file', 'rb').read()

xor = 'x0=0.35,miu=3'
f1 = open(f'xorxor', 'wb')
for i, c in enumerate(f):
    x = ord(xor[i % len(xor)])
    f1.write(bytes([c ^ x]))
    f1.close()
    print('next')

直接拿提示指令碼。執行。得到 flag.

Crypto

Simple

羊城杯 2020 原題

from sage.all import *
from Crypto.Util.number import *
from Crypto.Cipher import DES
import gmpy2
from Crypto.Util.number import *
from gmpy2 import invert

e1 = 1038188773022222237625162518466985515806685046439847462572843423800303080199415368325579099819361640945202226526678764311585592296933622966635366454130900252466567292666094830865094694540899938932650663694321540899409821558619513870070621174837528024755540950294728078653453000484865860920060355130142874882872471337494879275434166435493265146752291857135290428750750609423353579700984426964475724965353873095813181244686536072523222027403912142730610262067287620007571352094447066062529895627497159337248165671672168914514241613626520037706745398642583257608070477729851466078618962204332539106519787878047712382699
e2 = 2837849440271663829778449470456059993823700375016504578318494102782617180188657051885856137280051100635878402423110369686929227684421486015532180997159960436120141492683886715611434986294622600612428406093623932339780091710632795226634412256078611259843109876301975664056868908063144172636320692414857287719870275516722663234436495523740203192523105607062687910252368627072074836944313105637959564954309098651598325997792496430340003856687190484681832529188281328826421428597879086043647647886763379182416419551074016810300511817626177321217978912504879476086100668005286481779806010131350674761039391612993646202901
c = 5973798238952580291825915383143493132916118834759984908567429997405141389115327100612059752092101975323145558282778289524466024564450720131251849100687215493221989801105144437981685382023973692198113306045957788268110316519461230170693204752380105917975206409994893101671098451678847638671373239757408532363808224681853024689663345258120864348816343897379881239786554998688501997609152329902187048422237325117741778968505252184157273467466011959504548459297647302026380076579903441434135973514451254950835559924204821846949520738057940287763572642367638668413987340659205489659594044022422368411980101640782079189025
N = 26901814699902439156457451193693740730489294959491270367027927283506475930489639407729426818974347303153364758700002407059993182986763909124690390655890031474097185414651218374672254140022392199647526025638012909369532528422355530044873378287920255523382224453173638818751280227521077881224963029942704252587893395262633450759457753054490886171089835324182422639138198164026845488515879253564971977801724349440235209377091735281830263780308625603392942624306475075157394231585266792247387837984357822842056801420064918953837917678662504712605611080802179768683537742095990507008809197788025847612652983474906829809607

a = 0.356  # 731./2049
M1 = N ** 0.5
M2 = N ** (a + 1)
D = diagonal_matrix(ZZ, [N, M1, M2, 1])
M = matrix(ZZ, [[1, -N, 0, N ** 2], [0, e1, -e1, -e1 * N], [0, 0, e2, -e2 * N], [0, 0, 0, e1 * e2]]) * D
L = M.LLL()
t = vector(ZZ, L[0])
x = t * M ** (-1)
phi = int(x[1] / x[0] * e1)
d = invert(0x10001, phi)
m = pow(c, d, N)
print(long_to_bytes(m))

 

two old man

# -*- coding: utf-8 -*-
from Crypto.Util.number import long_to_bytes, isPrime
from gmpy2 import invert, powmod
from libnum import solve_crt
from functools import reduce

n = 85300075344029411815824595503988243445862905766678219075505308650733618833670564881852727486124268400610986787128098448019033364495139613324970241727110931819892696714818851281415775513570277910383275087114654129682377412912019832281317957560043184535419626656895668221654944747681971549122289940681069900407
c = 9573652589542765552302771253681350397003834739308979745013100413124314842798363931809688570564520116621700487372591176287735200842509675988724251662626729985842786542792501720096155870937426730816107184806453412679852267311433564241907769415712680798333238722253896962273334726781549003053182286964079196169
e = 65537
p = 9235803990126112015712488678718763955409551939176855113164196792808741000738495903574101715848666926223811357608313697206174389466866723210464201625526487
q = 9235803990126112015712488678718763955409551939176855113164196792808741000738495903574101715848666926223811357608313697206174389466866723210464201625528161

d = invert(e, (p-1)*(q-1))
assert p*q == n
m = pow(c, d, n)
d1 = invert(p-1, p)
print(f'd1 = {d1}')
m1 = m * d1 % p
print(f'm1 = {m1}')
s = reduce(lambda x,y: x * y % n, range(p, q), 1)
d2 = invert(s, q)
s = d2 * (q - 1) % q
d2 = invert(s, q)
print(f'd2 = {d2}')
m2 = m * d2 % q
print(f'm2 = {m2}')
m = solve_crt((m1, m2), (p, q))
print(long_to_bytes(m)[:-80])
b'flag{c7cfdbc1-729b-de11-239f-a473ec0637b8}'
 

Pwn

deadly

簽到題，直接將環境地址填上，執行 cat flag