Pavel Durovʼs service is positioned as the most secure messenger providing clients with maximum privacy during the communication process. The main difference from concurrent applications is that Telegram conversation history is protected by means of MTProto’s complex encryption algorithm. By the way, no one cryptography expert has still managed to hack the given protocol.
Telegram is a cloud service, so all text information, photos and video files are stored on the company’s servers. Such approach allows decreasing the load on the userʼs mobile hardware and provides access to his private data from any device. The information storage security is achieved through multiple encryption. Moreover, key codes are stored apart on remote servers, so a probability of information decryption is practically reduced to zero.
It is necessary to put a special focus on over-protected secret chats working on end-to-end encryption basis. In order to view history in the secret chat mode, physical access to the device is required. The entire message history is saved only on the sender and receiver’s smartphones/PC (if they did not install a self-destruct timer deleting information after a particular period of time). During the process of sending text, graphic or video data, encryption is carried out on basis of the key which is available to conversation partners but not to the server. Thus, only device owners are able to decrypt files and determine their ownership.
In standard chats, groups and supergroups, information is stored on the messenger’s servers, so any community member has access to it. For viewing conversation with some particular interlocutor, it is necessary just tap on his or her name. Further, recent messages will appear. The same also goes for group communities – when entering a group, it is possible to read new messages or view the previous ones.
As for the open supergroups, they are characterized by interesting feature. The entire message history is available both to community members and people who do not belong to it. Before entering a supergroup, a person may view recent messages and evaluate audience and its competence for making a decision.
It sometimes happens that you need to delete conversation with some particular user. The given procedure is carried out in several steps.
For mobile devices:
For PCs (variant 1):
For PCs (variant 2):
When it comes to standard chats, it is possible to clear message history only for an account by which the given request was made. As for the second conversation partner, the messages remain available and he may view them at any moment. The same is not true for secret chats – when a user deletes a message on one device, it is also removed from his interlocutor’s smartphone/PC.
Telegram is a comparatively new and non-profit project. For this reason, each byte of disk space is highly valued on the company’s servers. The developers have considered it unreasonable to create reserve copies which are frequently just a «dead weight» bringing no special benefit but significantly increasing the load on server equipment.
After message history deletion by each user, data disappears once and for all. It is impossible to restore them, so it is of great importance to think carefully before making such decision. This is especially true when a userʼs desire to clear message history is provoked by emotions and has no rational kernel.