1 """fontTools.misc.eexec.py -- Module implementing the eexec and 2 charstring encryption algorithm as used by PostScript Type 1 fonts. 3 """ 4 5 from __future__ import print_function, division, absolute_import 6 from fontTools.misc.py23 import * 7 8 def _decryptChar(cipher, R): 9 cipher = byteord(cipher) 10 plain = ( (cipher ^ (R>>8)) ) & 0xFF 11 R = ( (cipher + R) * 52845 + 22719 ) & 0xFFFF 12 return bytechr(plain), R 13 14 def _encryptChar(plain, R): 15 plain = byteord(plain) 16 cipher = ( (plain ^ (R>>8)) ) & 0xFF 17 R = ( (cipher + R) * 52845 + 22719 ) & 0xFFFF 18 return bytechr(cipher), R 19 20 21 def decrypt(cipherstring, R): 22 plainList = [] 23 for cipher in cipherstring: 24 plain, R = _decryptChar(cipher, R) 25 plainList.append(plain) 26 plainstring = strjoin(plainList) 27 return plainstring, int(R) 28 29 def encrypt(plainstring, R): 30 cipherList = [] 31 for plain in plainstring: 32 cipher, R = _encryptChar(plain, R) 33 cipherList.append(cipher) 34 cipherstring = strjoin(cipherList) 35 return cipherstring, int(R) 36 37 38 def hexString(s): 39 import binascii 40 return binascii.hexlify(s) 41 42 def deHexString(h): 43 import binascii 44 h = strjoin(h.split()) 45 return binascii.unhexlify(h) 46 47 48 def _test(): 49 testStr = "\0\0asdadads asds\265" 50 print(decrypt, decrypt(testStr, 12321)) 51 print(encrypt, encrypt(testStr, 12321)) 52 53 54 if __name__ == "__main__": 55 _test() 56
