People will tell you, that there is big gaping crypto vulnerability in Telegrams client-server crypto because it is not secure under CCA. In fact this is only c

People will tell you, that there is big gaping crypto vulnerability in Telegrams client-server crypto because it is not secure under CCA. In fact this is only certificational weakness (ie. attacker can replace message with different ciphertext that encodes exactly same message). The crypto is somewhat weird, but it is clear that motivation for the weirdness is getting small ciphertexts.