Bungie challenge decoder

bungie.py

import binascii

# This is the original puzzle from the mail sack!
puzzle = """
9B3E9D48B3A3C99D162D2A75E44FA14A0C3A9261C5873E6D0AB522D2A7
0E4C59D0E2D0A5063CD83524C38332659A51684583522C499663CFAF26A
48A9222C39F366CF9D4294187524C38B067449916B45A5063C59F3A2D38
33A25A8B4A7C5A7527D08B3AA488B26950A53E3D283369AE8F16745A506A
499D1E1CF89166499716A48934E3C59D169419932CC9A7068528B52A59A
F1664C5B1A7D59D122C4A106A548B4A7549F166D0993ECAE9F3AA488B1A
649A14E4C48AB21559D1E4C5934E74FA9667D5A552CD0930E0CC8B3A3C
99D162D2933A3C7A53EAD05D5E2D7A526A45A14A7C7A5066D3AF26A489F
56A4F9D169AE9F569508B3E84C8B127CE9F526499716A488B3AACD85169
2EAF22CBFAF1664C5952445A5160D28B1E94583522D2591E9419D122D29
D566C28B4A9D49F06850996634FA53EAD2AF26659874A0C6A8BA6C1B322
0D0B33EAC4934E0C7A5162ACA11694391067438B667D5831E9458ABABC
883526C1A9522D2A7269D49106A538B5A2CE934E6CFA5160D78B4E7CD8
B524419D3E745AF2664C8B5A2D293360C7933A2C9A94E2CC8D527C28AB
A0CE894E7ACAF161CF8916BC9A9220CDA1322D38B5A2CEA6B274FA93E7
45A6BA3418751D50A53E3D283369D0830E5C5895E4D4914E2D68B3A9C1
A5166CFA5160D78B4E7CD8B524419D424D491668529F1E9419B4EA48835
20D0A132CCF9D169AEB51694F8B4DFD78B3262CAF169D4933265491267
4BA9222D94F4A2C79F3E22EA14A2D4A9668419906A4185322AEAF163D283
4284C8B5E4D4916A2D29F169C19932A488B524CD8ABA2D68B3A74FAEBA
CC5A6BA445A515743833ACCFAB422CFA1322D38B16A488B35FD2931E454
9116945933AA48934E64F9D1EA45B151FD083569C5A93EA4197160CC9F3
A3CC9F3E5AEA11694391067438B52449A7220D385162CE835E4CCB31E0C
D8526A419932A48934EA499B15FD78B3262CA13E649A722A489F4E2D491
2674B933A3C383429AEB33EAC8835A2C19B426459D566C28B4A9D49F1A4
CE88BA441AD169CF9B163559C869D48366441A142CAE""".replace('\n', '')


def chunks(s, n):
    """Produce `n`-character chunks from `s`."""
    for start in range(0, len(s), n):
        yield s[start:start + n]

# After we have learned the hint from the PAX picture, we know we have to:
# "First convert the hexadecimal to binary. Then, regroup the bits into chunks equal to our favorite number.
# Finally, read as ASCII."

# This one liner takes the puzzle in hexadecimal form, converts it to binary in 7 bit chunks, and then
# converts those chunks into individual characters. It finally appends it all together in one human readable
# string!
paragraph = ''.join([binascii.unhexlify('%x' % int(c, 2)) for c in chunks(bin(int(puzzle, 16))[2:], 7)])
print 'Decoded paragraph:\n%s\n' % paragraph

# Based on hints from TheMissingLink and the paragraph, we know numbers are important.
# But there are no numbers in the paragraph, so let's convert it back to hexadecimal
# and look for sevens and zeroes.
backtohex = binascii.hexlify(paragraph)
print 'Hexadecimal representation of the paragraph:\n%s\n' % backtohex

# We can loop through the hexadecimal looking for the sevens and zeroes,
# count them, and also create a string out of them. We know from TheMissingLink
# there should be 91 total.
counter = 0
binary_string = ''
for c in backtohex:
    if c == '7' or c == '0':
        counter += 1
        binary_string += c

print 'Found %s sevens and zeroes!\n' % counter

# Since Bungie uses sevens instead of ones, we can replace the sevens with ones, and convert the resulting
# binary string to ASCII one character at a time. This produces the final answer, which is a link!
finalanswer = ''.join([binascii.unhexlify('%x' % int(c, 2)) for c in chunks(binary_string.replace('7', '1'), 7)])
print 'The final answer: %s\n' % finalanswer

pax_image.py

import Image
img = Image.open("PAX.png")

width, height = img.size
pixels = img.load()

all_pixels = []
# Only the last 86 pixels on the last two rows are of importance
for x in range(width - 86, width):
    for y in (368, 369):
        cpixel = pixels[x, y]
        all_pixels.append(cpixel)

solution = ""
for p in all_pixels[0::4]:
    solution += chr(p[0]) + chr(p[1]) + chr(p[2])

print solution