Lense

Keybase proof

I hereby claim:

• I am lense on github.
• I am lense (https://keybase.io/lense) on keybase.
• I have a public key whose fingerprint is CDC6 56E1 4573 D016 91CB 4E35 4596 4BC9 C3E2 AFE3

To claim this, I am signing this object:

Lense

// ==UserScript==
// @name        Automate Steam linkfilter
// @namespace   https://github.com/lense
// @description Skip the Steam link filter on trusted domains
// @include     https://steamcommunity.com/linkfilter/?url=*
// @version     1
// @grant       none
// @run-at document-start
// ==/UserScript==

Lense

# Preface:
#  I'm not putting this online because I think it's a particularly good
#  solution--it's buggy and thrown together. I'm instead uploading it because
#  of the sheer amount of time I spent on it. Making it public makes me feel
#  better for wasting 12 or so hours of my life on this problem, to not even
#  end up getting points for it. 6 of those were after getting the flag, but
#  uppercase instead of lowercase. A significant amount of time was also spent
#  trying to use the built in parser of rubinius to at least dump the rbc
#  instructions, but I have no idea how to write Ruby, and eventually decided
#  it would be easier to rewrite everything rather than do anything in Ruby.

Lense

#/usr/bin/env python

from Crypto.PublicKey import RSA, DSA
from Crypto.Random import random, atfork
from Crypto.Cipher import PKCS1_OAEP

import SocketServer,threading,os,time
import socket

from priv import privkey, privkey_enc

Lense

#!/usr/bin/env python

# https://github.com/pablocelayes/rsa-wiener-attack
import RSAwienerHacker

def int2ascii(n):
	# Cut off 0x and L
	h = hex(n)[2:-1]
	# Convert each hex byte to ascii char
	return "".join([chr(int(h[i:i+2], 16)) for i in range(0, len(h), 2)])

Lense

We found these System/360 punch cards and we need to extract the data. We already read the data off for you.

It looks encrypted. Can you help?

HINT: This is actually encrypted. With technology and techniques that were available in 1965

HINT: https://gist.github.com/withzombies/40554f02d6c7055fb0bc punchout.tar.xz-24504ddc1e81092010497ee49fc52e1c

Lense

SOLARIZED HEX     16/8 TERMCOL  XTERM/HEX   L*A*B      RGB         HSB
--------- ------- ---- -------  ----------- ---------- ----------- -----------
base03    #002b36  8/4 brblack  234 #1c1c1c 15 -12 -12   0  43  54 193 100  21
base02    #073642  0/4 black    235 #262626 20 -12 -12   7  54  66 192  90  26
base01    #586e75 10/7 brgreen  240 #585858 45 -07 -07  88 110 117 194  25  46
base00    #657b83 11/7 bryellow 241 #626262 50 -07 -07 101 123 131 195  23  51
base0     #839496 12/6 brblue   244 #808080 60 -06 -03 131 148 150 186  13  59
base1     #93a1a1 14/4 brcyan   245 #8a8a8a 65 -05 -02 147 161 161 180   9  63
base2     #eee8d5  7/7 white    254 #e4e4e4 92 -00  10 238 232 213  44  11  93
base3     #fdf6e3 15/7 brwhite  230 #ffffd7 97  00  10 253 246 227  44  10  99

Lense

###Good writeup is at https://github.com/p4-team/ctf/tree/master/2015-12-05-seccon/paillier_crypto_200#eng-version

I use the fact that h=co (mod n*n) to brute force n, which took around 45 minutes.
Then I factor n to get p and q, and make into phi. Then I plug everything into the "simpler variant" on https://en.wikipedia.org/wiki/Paillier_cryptosystem

Lense

Extract the key!

Written by RyanWithZombies

Update: The key is not "flag{ don't trust the Cheshire cat!! he works for the Queen of Hearts }". Sorry about that. It's an artifact from an easier version of this challenge. You need to extract key.jpg.

HINT:

CSAWLZ is a completely custom format! You won't find decompressing tools on the internet. We made it just for you. :)

Lense

Challenge

Title: brainfun
Competition: CSAW quals 2016
Category: Forensics
Points: 150
Description: Scrambled Fun for Everyone! Author: fang0654 <brainfun.png>

Background

• There's nothing hidden in the file other than the pixel data.
• The image is 512x512, but can be scaled down 32x32 to match the blocks to