Experiment with Davinci version 3 protocol encrypt / decrypt / upload (based on pythreedub)

decrypt.py

from Crypto.Cipher.AES import AESCipher, MODE_ECB, MODE_CBC

file = open("flatcube/flatcube-1-layer.3w", 'rb')
string = file.read()
enc_gcode = string[0x2000:]
aes = AESCipher("@xyzprinting.com@xyzprinting.com", mode=MODE_ECB, IV=chr(0)*16)
gcode = aes.decrypt(enc_gcode)
print gcode

encrypt.py

import time, serial, sys, string, struct, binascii
import Padding
from io import BytesIO
from Crypto.Cipher.AES import AESCipher, MODE_ECB, MODE_CBC

# read gcode
file = open("flatcube/flatcube-1-layer.gcode", 'rb')
lines = file.readlines()

# encrypt header
key = "@xyzprinting.com"
iv = chr(0)*16
aes = AESCipher(key, mode=MODE_CBC, IV=iv)
header_text = "".join([line for line in lines if line.startswith(";")])
padded = Padding.appendPadding(header_text)
encrypted_header = aes.encrypt(padded)

# encrypt fulltext
key = "@xyzprinting.com@xyzprinting.com"
iv = chr(0)*16
aes = AESCipher(key, mode=MODE_ECB, IV=iv)
fulltext = "".join(lines)
padded = Padding.appendPadding(fulltext)
encrypted_fulltext = aes.encrypt(padded)
crc32 = binascii.crc32(encrypted_fulltext)
crcstr = struct.pack(">l", crc32)

# write encrypted header and encrypted fulltext
bio = BytesIO()
bio.write("3DPFNKG13WTW")
bio.write(struct.pack("8B", 1, 2, 0, 0, 0, 0, 18, 76))
bio.write(chr(0)*4684)
bio.write("TagEJ256")
bio.write(struct.pack("4B", 0, 0, 0, 68))
bio.write(crcstr)
bio.write((chr(0)*(68 - len(crcstr))))
bio.write(encrypted_header)
left = 8192 - bio.tell()
bio.write((chr(0)*left))
bio.write(encrypted_fulltext)

print bio.getvalue()

upload.py

import time, serial, sys
import copy
import string
import os
from Crypto.Cipher.AES import AESCipher, MODE_ECB, MODE_CBC
import logging
import struct

log = logging.getLogger(__name__)

UploadCmd = "XYZv3/upload={filename},{size}{option}"
UploadDidFinishCmd = "XYZv3/uploadDidFinish"

ser = serial.Serial(
    port="/dev/tty.usbmodem1411",
    baudrate=115200,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS
)

def write(data):
    ser.write(data)
    ser.flush()

def writeline(data):
    write(data+"\n")

def readline():
    return ser.readline()

def readlines(expect=None):
    buf = ""
    line = None
    while line is None or line:
        line = readline()
        if line:
            buf += line
            if line.strip() == expect:
                break
            elif line.strip() == "E0":
                return buf
    return buf

def wait_for_ok(expect="ok"):
    resp = readlines(expect=expect)
    if not resp or resp.strip() != "ok":
        raise Exception("Expected token not found: {}, got '{}' instead".format(expect,resp.strip()))
    

f = open("flatcube/flatcube-1-layer.3w", 'rb')
data = f.read()
size = os.fstat(f.fileno()).st_size

writeline(UploadCmd.format(filename="temp.gcode", size=size, option=""))
wait_for_ok();

chunks = (len(data)+8191) / 8192
prev = ""
blocksize = 8192
for n in range(0, chunks):
    log.debug("Sending file chunk {}/{}".format(n, chunks))
    chunk = struct.pack(">l", n) + struct.pack(">l", blocksize)
    start = 8192*n
    chunk += data[start:start+8192]
    chunk += "\x00\x00\x00\x00"
    write(chunk)
    wait_for_ok()

write(UploadDidFinishCmd)

print "done"