weissman.py

def read_chunk(f):
    global data

    chunk_type = ord(f.read(1))
    if chunk_type % 2 == 1:
        chunk_size = chunk_type >> 1

        data.append(f.read(chunk_size))
        orig_data.append(orig.read(chunk_size))

        return True
    else:
        chunk_hash = f.read(2).encode('hex')
        chunk_size = chunk_type >> 1

        # print "Chunk type: %02x %s, id: %d" % (chunk_type, chunk_hash, len(data))
        data.append("\x00" * chunk_size)
        return True

f = open('key.csawlz', 'rb')
orig = open('csawlz_source.html', 'rb')

f.read(0x2c)

data = []
orig_data = []

try:
    while read_chunk(f):
        pass
except Exception:
    pass

open('outkey.jpg', 'wb').write(''.join(data))