110 lines
2.2 KiB
Python
110 lines
2.2 KiB
Python
#
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# Purpose: Write 2 new JPG image files => PicSeal JPG Files
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#
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# Data: public key, private key, image hash, image signature
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# Has: JPG fingerprint
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#
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# Big-endian
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# Pub: [picseal:7|type:1|sig:512|pubkey:550]
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# Pvt: [picseal:7|type:1|sig:512|pvtkey:2347]
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#
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import struct
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import logging
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from Crypto.PublicKey import RSA
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class JpgPicSeal:
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app15_marker = b'\xff\xef'
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# ascii code for "picseal"
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picseal_marker = b'\x70\x69\x63\x73\x65\x61\x6C'
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def __init__(self, sig=None):
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self.sig = sig
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self.sig_data = None
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#
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# READ
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#
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def isPicSeal(self, buf):
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if (buf == JpgPicSeal.picseal_marker):
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return True
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return False
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#
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def deserialize(self, fhr):
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# read type 0x01 is public key, 0x02 private key
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buf = fhr.read(1)
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pubpvt = struct.unpack('>B', buf)
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self.sig_data = fhr.read(512)
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if (pubpvt == b'\x01'):
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#pub
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buf = fhr.read(550)
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self.sig.importPubKey(buf)
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else:
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#pvt
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buf = fhr.read(2347)
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self.sig.importPvtKey(buf)
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def readPub(self):
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pass
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def readPvt(self):
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pass
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#
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# WRITE
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#
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#
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def serilize(self, fname):
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pass
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#
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# input is the Crypto Sig class
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#
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def writePub(self, fhw):
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self.__writeData(fhw, self.sig.sig_data, self.sig.getPubKeyDER(), b'\x01')
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#
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# input is the Crypto Sig class
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#
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def writePvt(self, fhw):
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self.__writeData(fhw, self.sig.sig_data, self.sig.getPvtKeyDER(), b'\x02')
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#
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def __writeData(self, fhw, sig_data, keyder, pubpvt):
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# must include 2 bytes of length too
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size = 2
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size += len(JpgPicSeal.picseal_marker)
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size += len(sig_data)
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size += len(keyder)
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logging.debug("picseal marker length: {}".format(str(len(JpgPicSeal.picseal_marker))))
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logging.debug("hash size: {}".format(str(len(sig_data))))
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logging.debug("key size: {}".format(str(len(keyder))))
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#
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# write header
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# write app marker
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fhw.write(JpgPicSeal.app15_marker)
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# write the size of picseal record
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fhw.write(size.to_bytes(2, byteorder='big'))
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#
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# write picseal data
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# write picseal marker
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fhw.write(JpgPicSeal.picseal_marker)
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fhw.write(pubpvt)
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# write hash of image
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fhw.write(sig_data)
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# write the public key data
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fhw.write(keyder)
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