Telegram does not store private keys only on client. On the other hand telegram splits the private key and stores in multiple severs in several countries making

Telegram does not store private keys only on client. On the other hand telegram splits the private key and stores in multiple severs in several countries making it legally very very hard to process requests. But this also means the founders or just some developer who has access to the servers can read the messages as they have access to private keys. Signal app is more secure.Signal app does not store private keys on the server. The following faq is from telegram site. Q: Do you process data requests? Secret chats use end-to-end encryption, thanks to which we don't have any data to disclose. To protect the data that is not covered by end-to-end encryption, Telegram uses a distributed infrastructure. Cloud chat data is stored in multiple data centers around the globe that are controlled by different legal entities spread across different jurisdictions. The relevant decryption keys are split into parts and are never kept in the same place as the data they protect. As a result, several court orders from different jurisdictions are required to force us to give up any data. Thanks to this structure, we can ensure that no single government or block of like-minded countries can intrude on people's privacy and freedom of expression. Telegram can be forced to give up data only if an issue is grave and universal enough to pass the scrutiny of several different legal systems around the world. To this day, we have disclosed 0 bytes of user data to third parties, including governments. ### End of Faq #### Even the secret chats in telegram are not secret because the protocol is custom developed by amateurs devs. It is not tested and have seen some articles on methods to attack, could not get the link now.