def _read_7z_aes256_sha256(self, coder, input, level):
if not self._archive.password:
raise NoPasswordGivenError()
# TODO: this needs some sanity checks
firstbyte = coder['properties'][0]
if not IS_PYTHON3:
firstbyte = ord(firstbyte)
numcyclespower = firstbyte & 0x3f
if firstbyte & 0xc0 != 0:
saltsize = (firstbyte >> 7) & 1
ivsize = (firstbyte >> 6) & 1
secondbyte = coder['properties'][1]
if not IS_PYTHON3:
secondbyte = ord(secondbyte)
saltsize += (secondbyte >> 4)
ivsize += (secondbyte & 0x0f)
assert len(coder['properties']) == 2+saltsize+ivsize
salt = coder['properties'][2:2+saltsize]
iv = coder['properties'][2+saltsize:2+saltsize+ivsize]
assert len(salt) == saltsize
assert len(iv) == ivsize
assert numcyclespower <= 24
if ivsize < 16:
iv += bytes('\x00'*(16-ivsize), 'ascii')
else:
salt = iv = bytes('', 'ascii')
password = self._archive.password.encode('utf-16-le')
key = pylzma.calculate_key(password, numcyclespower, salt=salt)
cipher = pylzma.AESDecrypt(key, iv=iv)
if not input:
self._file.seek(self._src_start)
uncompressed_size = self._uncompressed[level]
if uncompressed_size & 0x0f:
# we need a multiple of 16 bytes
uncompressed_size += 16 - (uncompressed_size & 0x0f)
input = self._file.read(uncompressed_size)
result = cipher.decrypt(input)
return result
def _read_7z_aes256_sha256(self, coder, input, level):
if not self._archive.password:
raise NoPasswordGivenError()
# TODO: this needs some sanity checks
firstbyte = coder['properties'][0]
if not IS_PYTHON3:
firstbyte = ord(firstbyte)
numcyclespower = firstbyte & 0x3f
if firstbyte & 0xc0 != 0:
saltsize = (firstbyte >> 7) & 1
ivsize = (firstbyte >> 6) & 1
secondbyte = coder['properties'][1]
if not IS_PYTHON3:
secondbyte = ord(secondbyte)
saltsize += (secondbyte >> 4)
ivsize += (secondbyte & 0x0f)
assert len(coder['properties']) == 2 + saltsize + ivsize
salt = coder['properties'][2:2 + saltsize]
iv = coder['properties'][2 + saltsize:2 + saltsize + ivsize]
assert len(salt) == saltsize
assert len(iv) == ivsize
assert numcyclespower <= 24
if ivsize < 16:
iv += bytes('\x00' * (16 - ivsize), 'ascii')
else:
salt = iv = bytes('', 'ascii')
password = self._archive.password.encode('utf-16-le')
key = pylzma.calculate_key(password, numcyclespower, salt=salt)
cipher = pylzma.AESDecrypt(key, iv=iv)
if not input:
self._file.seek(self._src_start)
uncompressed_size = self._uncompressed[level]
if uncompressed_size & 0x0f:
# we need a multiple of 16 bytes
uncompressed_size += 16 - (uncompressed_size & 0x0f)
input = self._file.read(uncompressed_size)
result = cipher.decrypt(input)
return result