Crypto

picoCTF 2018: SpyFi

問題 問題文 James Brahm, James Bond's less-franchised cousin, has left his secure communication with HQ running, but we couldn't find a way to steal his agent identification code. Can you? Conect with nc 2018shell2.picoctf.com 37131. Sourc…

picoCTF 2017: Weird RSA

問題 問題文 We recovered some data. It was labeled as RSA, but what in the world are dq and dp Can you decrypt the ciphertext for us 問題概要 解答例 指針 中国人剰余定理 解説 与えられたファイルの中身を表示してみる. $ cat RSA.txt c: 95272795…

EKOPARTY PRE-CTF 2015: Perfect security

問題 問題文 It is not maybe so perfect. Hints: Use the golden math! crypto200.zip ※問題ファイルは下記のものを利用できる。 https://github.com/ctfs/write-ups-2015/tree/master/ekoparty-pre-ctf-2015/crypto/perfect-security 問題概要 暗号処理を…

SECCON2017 Online CTF: Ps and Qs

問題 問題文 Ps and Qs Decrypt it. update: we fixed the flag, please try to submit again. psqs1-0dd2921c9fbdb738e51639801f64164dd144d0771011a1dc3d55da6fbcb0fa02.zip (pass:seccon2017) 問題ファイルは下記のリンクのものを利用できる。 https://gi…

34C3 Junior CTF: dotr

問題 問題文 I implemented some crypto and encrypted my secret: 03_duCbr5e_i_rY_or cou14:L4G f313_Th_etrph00 Wh03UBl_oo?n07!_e Can you get it back? 問題概要 暗号化処理をする Python3 スクリプトと暗号文が与えられる。 平文を復号せよ。 解答例 …

AlexCTF: CR3 What is this encryption?

問題 問題文 Fady assumed this time that you will be so n00b to tell what encryption he is using he send the following note to his friend in plain sight : p=0xa6055ec186de51800ddd6fcbf0192384ff42d707a55f57af4fcfb0d1dc7bd97055e8275cd4b78ec63…