michael mzhang28

Data:

http://www.apk4fun.com/apk/1299/

Solution:

This is just a really difficult challenge. First, decompile snapchat.apk using a tool or a service like decompileandroid. Extact the src folder. Yay. Java.

The first step is to do a little bit of research on Snapchat decryption. Your research will probably lead you to this repo. However, it's outdated. Cry slowly. You should realize at this point that you need the Android ID to do anything. Use grep to search for android_id in src. This will reveal locations in the code that obtain the Android ID from the phone. You will eventually find in com.flurry.sdk.ea the following:

Keybase proof

I hereby claim:

I am iptq on github.
I am failedxyz (https://keybase.io/failedxyz) on keybase.
I have a public key ASAOyYr2aYI5dkkI2c1UXnrjbb5t1l9ICUk__yJZpjvtIgo

To claim this, I am signing this object:

Keybase proof

I hereby claim:

I am iptq on github.
I am michaelz (https://keybase.io/michaelz) on keybase.
I have a public key ASCEhMaJMl3DkJKGSXc8q1Nr5FIMVapUMwtEbQkCH7vIQAo

To claim this, I am signing this object:

Keybase proof

I hereby claim:

I am iptq on github.
I am michaelz (https://keybase.io/michaelz) on keybase.
I have a public key ASArajdaYzbql7aXaUnBl6G5yasMz7nhOIgkLEnDqEQdhwo

To claim this, I am signing this object:

	#include <stdio.h>
	#include <stdlib.h>
	#include <fcntl.h>

	int main(int argc, char **argv) {
	int score = 0;
	printf("CollageBored (R) Advanced Placement Literature Grader\n");
	if (argc != 2) {
	printf("Usage: %s [essay]\n", argv[0]);
	return 1;

	~ » telnet wayward.tcp.easyctf.com 8580 michael@zhang
	Trying 45.55.88.134...
	Connected to wayward.tcp.easyctf.com.
	Escape character is '^]'.
	Please enter your pilot key: hello
	The current time is: 1489720845.28
	Please enter the coordinates (x, y) you would like to hit:
	world
	Sorry, you didn't enter valid coordinates.
	Connection closed by foreign host.

	#!/usr/bin/env python

	from PIL import Image

	A = Image.open("A.png")
	B = Image.open("B.png")

	dA = A.load()
	dB = B.load()

	#!/usr/bin/env python

	frequencies = {'a': 0.0651738, 'b': 0.0124248, 'c': 0.0217339, 'd': 0.0349835, 'e': 0.1041442, 'f': 0.0197881, 'g': 0.0158610, 'h': 0.0492888, 'i': 0.0558094, 'j': 0.0009033, 'k': 0.0050529, 'l': 0.0331490, 'm': 0.0202124,
	'n': 0.0564513, 'o': 0.0596302, 'p': 0.0137645, 'q': 0.0008606, 'r': 0.0497563, 's': 0.0515760, 't': 0.0729357, 'u': 0.0225134, 'v': 0.0082903, 'w': 0.0171272, 'x': 0.0013692, 'y': 0.0145984, 'z': 0.0007836, ' ': 0.1918182}


	def single_byte_xor(b, s):
	""" Performs XOR of the single byte against every character in string. """
	assert len(b) == 1
	x = ord(b)

	chars = " FuMlX%3kBJ:.N*epqA0Lh=En/diT1cwyaz$7SH,OoP;rUsWv4g\\Z<tx(8mf>-#I?bDYC+RQ!K5jV69&)G"

	def get_key(seed):
	result = ""
	seed = 16631 * (seed % 0x7fffffff) + 511115
	for i in range(16):
	result += byte[seed % 0x7fffffff % 82]
	seed = 16631 * (seed % 0x7fffffff) + 511115
	result += chars[seed % 0x7fffffff % 82]
	return result

	call plug#begin()

	Plug 'vim-syntastic/syntastic'
	Plug 'tomasiser/vim-code-dark'
	Plug 'vim-airline/vim-airline'
	Plug 'scrooloose/nerdtree'
	Plug 'rhysd/vim-clang-format'
	Plug 'kien/ctrlp.vim'

	call plug#end()