def _decrypt(self, stream):
"""
Build the master key from header settings and key-hash list.
Start reading from `stream` after the header and decrypt all the data.
Remove padding as needed and feed into hashed block reader, set as
in-buffer.
"""
super(KDB4File, self)._decrypt(stream)
ciphername = self.header.ciphers.get(self.header.CipherID,
self.header.CipherID)
if ciphername == 'AES':
data = aes_cbc_decrypt(stream.read(), self.master_key,
self.header.EncryptionIV)
data = unpad(data)
elif ciphername == 'Twofish':
data = twofish_cbc_decrypt(stream.read(), self.master_key,
self.header.EncryptionIV)
data = unpad(data)
else:
raise IOError('Unsupported decryption type: %s' %
codecs.encode(ciphername, 'hex'))
length = len(self.header.StreamStartBytes)
if self.header.StreamStartBytes == data[:length]:
# skip startbytes and wrap data in a hashed block io
self.in_buffer = HashedBlockIO(initial_bytes=data[length:])
# set successful decryption flag
self.opened = True
else:
raise IOError('Master key invalid.')
def test_twofish_cbc_decrypt(self):
self.assertEqual(twofish_cbc_encrypt(b'datamustbe16byte', sha256(b'b'),
b'ivmustbe16bytesl'),
b'\xd4^&`\xe1j\xfd{\xeb\x04{\x90f\xed\xebi')
self.assertEqual(twofish_cbc_encrypt(b'datamustbe16byte', sha256(b'c'),
b'ivmustbe16bytesl'),
b'\xb3\x86\xbe\x0ficZW\x92P\xeb\x17\xa8\xa8\xac\xe8')
self.assertEqual(twofish_cbc_decrypt(b'K\x07q\xad\xd0\x8d\xb9\x0f\x15\xef\x87\x089\xc3\x83\x9c',
sha256(b'd'), b'ivmustbe16bytesl'),
b'datamustbe16byte')
def _decrypt(self, stream):
super(KDB3File, self)._decrypt(stream)
if self.header.encryption_flags[self.header.Flags-1] == 'AES':
data = aes_cbc_decrypt(stream.read(), self.master_key,
self.header.EncryptionIV)
data = unpad(data)
elif self.header.encryption_flags[self.header.Flags-1] == 'Twofish':
data = twofish_cbc_decrypt(stream.read(), self.master_key,
self.header.EncryptionIV)
data = unpad(data)
else:
raise IOError('Unsupported encryption type: %s'%self.header.encryption_flags.get(self.header['Flags']-1, self.header['Flags']-1))
if self.header.ContentHash == sha256(data):
# put data in bytes io
self.in_buffer = io.BytesIO(data)
# set successful decryption flag
self.opened = True
else:
raise IOError('Master key invalid.')