#!/usr/bin/env python
# -*- coding: utf-8 -*-
from Crypto.Util.number import *
import random
n = 2 ** 512
m = random.randint(2, n-1) | 1
c = pow(m, bytes_to_long(flag), n)
print 'm = ' + str(m)
print 'c = ' + str(c)
# m = 391190709124527428959489662565274039318305952172936859403855079581402770986890308469084735451207885386318986881041563704825943945069343345307381099559075
# c = 6665851394203214245856789450723658632520816791621796775909766895233000234023642878786025644953797995373211308485605397024123180085924117610802485972584499
題目很…一看就嫩看懂!but…
打開Ubuntu,安裝sagemath,開算!
n = 2 ** 512
m = 391190709124527428959489662565274039318305952172936859403855079581402770986890308469084735451207885386318986881041563704825943945069343345307381099559075
c=6665851394203214245856789450723658632520816791621796775909766895233000234023642878786025644953797995373211308485605397024123180085924117610802485972584499
ZmodN = Zmod(2^512)
m = ZmodN(m)
c = ZmodN(c)
c.log(m)
hex(56006392793405651552924479293096841126763872290794186417054288110043102953612574215902230811593957757)
最後的輸出16進制結果
'0x666c61677b35663935636139332d313539342d373632642d656430622d6139313339363932636234617d'
16進制再轉爲字符串
在線轉換網址:https://www.sojson.com/hexadecimal.html
flag{5f95ca93-1594-762d-ed0b-a9139692cb4a}
附 SageMath的安裝使用方法:
下載地址
http://www.sagemath.org/download-linux.html
1. windows版
2. linux Debian系的kali,或者ubuntu
上面的網址隨便選個亞洲的鏡像,然後下載,扔進linux
下面的圖是windows的在:https://github.com/sagemath/sage-windows/releases/tag/0.6.0-9.0
官方教程
http://doc.sagemath.org/html/en/tutorial/index.html
翻譯參考
https://www.lainme.com/doku.php/topic/sage/start
下面以自帶py2,3的 kali 作演示:
我很早之前安裝的時候,解壓時間特別特別長,等不及沒注意直接 ./sage
安裝就會出大問題!!!
耐心!細心!恆心!
選中壓縮包,右鍵在此解壓
或者命令行
tar xvf sage-9.0-Debian_GNU_Linux_9-x86_64.tar.bz2
解壓後的樣子:
進解壓的文件夾裏
cd SageMath/
在這裏空白處,右鍵打開終端輸入:
./sage
Done!
Ubuntu 自帶py3,無py2的的環境安裝故障
ubuntu ./sage後報錯
已安裝py3
運行reloacte.py
usr/bin/env python 沒有這個目錄
打開報錯relocate-once.py,在第一行python後面加3,改爲usr/bin/env python3 讓她找到python的目錄即可解決!