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synacor.py/tools/decrypt_data.py

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2017-02-05 20:45:04 +11:00
#!/usr/bin/env python3
# synacor.py - An implementation of the Synacor Challenge
# Copyright © 2017 RunasSudo
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import struct
import sys
if len(sys.argv) < 3:
print('Usage: {} <input> <output>'.format(sys.argv[0]))
else:
# Read code into memory
SYN_MEM = [0] * 32768
with open(sys.argv[1], 'rb') as data:
i = 0
while True:
byteData = data.read(2)
if len(byteData) < 2:
break
SYN_MEM[i] = struct.unpack('<H', byteData)[0]
i += 1
# Emulate 06bb
for R2 in range(0x17b4, 0x7562):
R1 = SYN_MEM[R2]
R1 ^= pow(R2, 2, 32768)
R1 ^= 0x4154
SYN_MEM[R2] = R1
# Write
with open(sys.argv[2], 'wb') as f:
f.write(struct.pack('<32768H', *SYN_MEM))