SkyLi
128 lines
4.6 KiB
Python
128 lines
4.6 KiB
Python
# Copyright (C) 2024 Texas Instruments Incorporated - http://www.ti.com/
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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#
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# Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the
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# distribution.
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#
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# Neither the name of Texas Instruments Incorporated nor the names of
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# its contributors may be used to endorse or promote products derived
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# from this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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from Crypto.Cipher import AES
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from enum import Enum
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import hashlib
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class cipherMode(Enum):
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MODE_GCM = 0x0040
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MODE_CTR = 0x0030
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def hex_string_to_txt(filename, hex_string):
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o = open(filename, 'w')
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o.write("@00000010\n")
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i = 0
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for x in range(0, len(hex_string), 2):
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o.write(hex_string[x] + hex_string[x+1])
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if(i < 15):
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o.write(" ")
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else :
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o.write("\n")
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i = (i + 1) % 16
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if(i != 0):
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# pad out header to nearest 128-bit buffer such that
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# UniFlash doesn't complain
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while i < 15:
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o.write("00 ")
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i += 1
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o.write("00\n")
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# o.write('q')
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o.close()
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def old_gcm_header():
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#get key from private key-type file
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key = bytes.fromhex("feffe992 8665731c 6d6a8f94 67308308")
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nonce = bytes.fromhex("cafebabe facedbad decaf888")
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aad = bytes.fromhex("feedface deadbeef feedface deadbeef abaddad2")
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plaintext = bytes.fromhex("d9313225 f88406e5 a55909c5 aff5269a \
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86a7a953 1534f7da 2e4c303d 8a318a72 \
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1c3c0c95 95680953 2fcf0e24 49a6b525 \
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b16aedf5 aa0de657 ba637b39")
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#calculate the key hash
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key_hash = hashlib.sha256(key).hexdigest()
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cipher = AES.new(key, AES.MODE_GCM, nonce)
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cipher.update(aad)
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(ciphertext, tag) = cipher.encrypt_and_digest(plaintext)
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#numbers are given in 16-bit little endian
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first_type = "9901004000"
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second_key = "55002000" + key_hash
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third_tag = "50001000" + tag.hex()
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fourth_iv = "51000C00" + nonce.hex()
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fifth_aad = "52001400" + aad.hex()
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hex_string_to_txt(first_type + second_key + third_tag + fourth_iv + fifth_aad)
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class Encryptor:
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mode = AES.MODE_GCM
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key = bytes.fromhex("feffe992 8665731c 6d6a8f94 67308308")
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nonce = bytes.fromhex("cafebabe facedbad decaf888")
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aad = bytes.fromhex("feedface deadbeef feedface deadbeef abaddad2")
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def __init__(self, cipherfile):
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self.cipherfile = cipherfile
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self.cipher = AES.new(Encryptor.key, Encryptor.mode, Encryptor.nonce)
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self.cipher.update(Encryptor.aad)
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self.length = b'\x00\x00\x00\x00'
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def update(self, aad):
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self.cipher.update(aad)
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def encrypt(self, plaintext):
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return self.cipher.encrypt(plaintext)
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def digest(self):
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return self.cipher.digest()
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def set_image_length(self, length):
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self.length = length.to_bytes(4, byteorder='little')
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def generate_header(self):
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tag = self.cipher.digest()
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key_hash = hashlib.sha256(Encryptor.key).hexdigest()
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first_type = "99994000"
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second_key = "55002000" + key_hash
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third_tag = "50001000" + tag.hex()
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fourth_iv = "51000C00" + Encryptor.nonce.hex()
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fifth_length = "52000400" + self.length.hex()
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sixth_aad = "53001400" + Encryptor.aad.hex()
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end_of_header = "AAAA"
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hex_string_to_txt(self.cipherfile, first_type + second_key + third_tag + fourth_iv +
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fifth_length + sixth_aad + end_of_header)
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