niklasb

from sage.all import continued_fraction, Integer, inverse_mod

pubkey = (1696852658826990842058316561963467335977986730245296081842693913454799128341723605666024757923000936875008280288574503060506225324560725525210728761064310034604441130912702077320696660565727540525259413564999213382434231194132697630244074950529107794905761549606578049632101483460345878198682237227139704889943489709170676301481918176902970896183163611197618458670928730764124354693594769219086662173889094843054787693685403229558143793832013288487194871165461567L, 814161885590044357190593282132583612817366020133424034468187008267919006610450334193936389251944312061685926620628676079561886595567219325737685515818965422518820810326234612624290774570873983198113409686391355443155606621049101005048872030700143084978689888823664771959905075795440800042648923901406744546140059930315752131296763893979780940230041254506456283030727953969468933552050776243515721233426119581636614777596169466339421956338478341355508343072697451L, 17101222758731850777

elliptic-shiho

from scryptos import *
import hashlib
import gmpy
'''
References: 
[1] Hitachi, Ltd. 2001. Specification of HIME(R) CryptoSystem - http://www.hitachi.com/rd/yrl/crypto/hime/HIME_R_specE.pdf
'''
SECRET = 'ASISCTF-17'

C0 = [ hashlib.sha1(SECRET[i:] + SECRET[:i]).digest()[:16] for i in xrange(10) ]

elliptic-shiho

from sage.all import *
# Original: https://github.com/mimoo/RSA-and-LLL-attacks/blob/master/boneh_durfee.sage

dimension_min = 7

def remove_unhelpful(BB, monomials, bound, current):
  if current == -1 or BB.dimensions()[0] <= dimension_min:
    return BB
  for ii in range(current, -1, -1):
    if BB[ii, ii] >= bound:

ymgve

function get_flag() {
    s = "ASIS{";
    var r0 = 65;
    var r7 = 0;
    for (var r8 = 0; r8 <= 20; r8++) {
        var r9 = 47;
        r9 = r9 < r0;
        if (!(r9 < 58)) {
            r9 = 64;
            r9 = r9 < r0;

ymgve

import socket, struct, os, binascii, base64, subprocess
import telnetlib   

import base58

def readline(sc, show = True):
    res = ""
    while len(res) == 0 or res[-1] != "\n":
        data = sc.recv(1)
        if len(data) == 0:

hellman

#-*- coding:utf-8 -*-

"""
In this challenge we have a Paillier cryptosystem.
We are given a decryption oracle, which leaks only one bit in the middle of the plaintext.

Due to homomorphic properties of the Paillier cryptosystem, we can recover the full decryption using such an oracle.

1. First, we recover the lower half of the message bit-by-bit.
This can be done by manipulating and observing the carry bit going through the pinhole,

hellman

#!/usr/bin/env ruby
require 'securerandom'
## Parameters
P = 115792089237316195423570985008687907853269984665640564039457584007913129639747
N = 100
K = 25
L = 38 # The number of liars

def apply_polynomial(coeffs, x)
    r = 0

hellman

#include <iostream>
#include <stdlib.h>
using namespace std;

#define REP(i,x) for(int i = 0; i < (int)x; i++)
#define M 8

int N;
string s[1000];
long q[M], p[M], hs[M][1000], hr[M][1000];

rkmylo

# uncompyle6 version 2.9.11
# Python bytecode 3.5 (3350)
# Decompiled from: Python 2.7.6 (default, Oct 26 2016, 20:30:19)
# [GCC 4.8.4]
# Embedded file name: /app/rFileStorage/__init__.py
# Compiled at: 2017-04-09 12:19:02
# Size of source mod 2**32: 1891 bytes
from flask import Flask, request, send_file, make_response
from hashlib import md5
from time import time

rkmylo

# coding: utf-8

"""
Unfortunately solved 20 minutes after the end of the CTF :(
"""

import re
import sys
import string
import requests