MarlinFirmware/buildroot/share/PlatformIO/scripts/lerdge.py

#
# buildroot/share/PlatformIO/scripts/lerdge.py
# Customizations for Lerdge build environments:
#   env:LERDGEX  env:LERDGEX_usb_flash_drive
#   env:LERDGES  env:LERDGES_usb_flash_drive
#   env:LERDGEK  env:LERDGEK_usb_flash_drive
#
import os,marlin
Import("env")

from SCons.Script import DefaultEnvironment
board = DefaultEnvironment().BoardConfig()

def encryptByte(byte):
	byte = 0xFF & ((byte << 6) | (byte >> 2))
	i = 0x58 + byte
	j = 0x05 + byte + (i >> 8)
	byte = (0xF8 & i) | (0x07 & j)
	return byte

def encrypt_file(input, output_file, file_length):
	input_file = bytearray(input.read())
	for i in range(len(input_file)):
		input_file[i] = encryptByte(input_file[i])
	output_file.write(input_file)

# Encrypt ${PROGNAME}.bin and save it with the name given in build.encrypt
def encrypt(source, target, env):
	fwpath = target[0].path
	enname = board.get("build.encrypt")
	print("Encrypting %s to %s" % (fwpath, enname))
	fwfile = open(fwpath, "rb")
	enfile = open(target[0].dir.path + "/" + enname, "wb")
	length = os.path.getsize(fwpath)

	encrypt_file(fwfile, enfile, length)

	fwfile.close()
	enfile.close()
	os.remove(fwpath)

if 'encrypt' in board.get("build").keys():
	if board.get("build.encrypt") != "":
		marlin.add_post_action(encrypt)
else:
	print("LERDGE builds require output file via board_build.encrypt = 'filename' parameter")
	exit(1)