def decrypt(self, senderKeyMessageBytes):
"""
:type senderKeyMessageBytes: bytearray
"""
try:
record = self.senderKeyStore.loadSenderKey(self.senderKeyName)
if record.isEmpty():
raise NoSessionException("No sender key for: %s" % self.senderKeyName)
senderKeyMessage = SenderKeyMessage(serialized=bytes(senderKeyMessageBytes))
senderKeyState = record.getSenderKeyState(senderKeyMessage.getKeyId())
senderKeyMessage.verifySignature(senderKeyState.getSigningKeyPublic())
senderKey = self.getSenderKey(senderKeyState, senderKeyMessage.getIteration())
plaintext = self.getPlainText(senderKey.getIv(), senderKey.getCipherKey(), senderKeyMessage.getCipherText())
self.senderKeyStore.storeSenderKey(self.senderKeyName, record)
return plaintext
except (InvalidKeyException, InvalidKeyIdException) as e:
raise InvalidMessageException(e)
def encrypt(self, paddedPlaintext):
"""
:type paddedPlaintext: str
"""
paddedPlaintext = bytearray(paddedPlaintext.encode() if sys.version_info > (3, 0) else paddedPlaintext)
try:
record = self.senderKeyStore.loadSenderKey(self.senderKeyName)
senderKeyState = record.getSenderKeyState()
senderKey = senderKeyState.getSenderChainKey().getSenderMessageKey()
ciphertext = self.getCipherText(senderKey.getIv(), senderKey.getCipherKey(), paddedPlaintext)
senderKeyMessage = SenderKeyMessage(
senderKeyState.getKeyId(), senderKey.getIteration(), ciphertext, senderKeyState.getSigningKeyPrivate()
)
senderKeyState.setSenderChainKey(senderKeyState.getSenderChainKey().getNext())
self.senderKeyStore.storeSenderKey(self.senderKeyName, record)
return senderKeyMessage.serialize()
except InvalidKeyIdException as e:
raise NoSessionException(e)
