Telegram

Telegram's listing opens with scale — "one of the top 5 most downloaded apps in the world with over 1 billion active users", a figure from the company that we have not verified — and then organises everything under a column of capitalised headings. The heading that matters most here is SECURE: it says that "everything on Telegram, including chats, groups, media, etc. is encrypted", and the ciphers it names are 256-bit AES and 2048-bit RSA. End-to-end encryption appears in the listing exactly once, further down, and it is offered as an extra for "those interested in maximum privacy" rather than as the default.

You sign up with a phone number and your messages sync across every device, including the desktop apps, which the listing stresses run standalone rather than through your phone. Groups hold up to 200,000 members, files of any type go up to 2 GB each, and bots can be set up to do specific jobs — scale and file size are what the listing means by "powerful". Media and chat history live in Telegram's cloud rather than on your device, which is what makes the multi-device sync work. Secret Chats are the separate mode: they are opt-in, they are not synced to the cloud, and they can be programmed to self-destruct from both devices.

The listing claims "100% FREE & OPEN" and points at a documented free API, open-source apps and verifiable builds that let anyone check the app matches the published source. It describes no subscription and no paid tier anywhere, so the free claim arrives unqualified: a reader learns that the listing says everything costs nothing, and nothing about whether anything is sold.

This is the most interesting encryption section among the four reviewed here, because of what it says and where it says it. The SECURE heading says everything is encrypted and names 256-bit AES, 2048-bit RSA and a Diffie–Hellman key exchange — all of which describe how traffic is protected and how data is stored, and none of which is a claim that Telegram cannot read your messages. End-to-end encryption, which is that claim, is mentioned once and attached to Secret Chats, described as being for those who want "maximum privacy". The distinction is worth being precise about: a message in an ordinary Telegram chat is encrypted on its way and encrypted in Telegram's cloud, but it is not end-to-end encrypted, and the listing never says that it is. The privacy paragraph makes three further claims — no third-party access, no ads built on your data, and the ability to delete any message for both sides without a trace — and the last is the one to read carefully, because deleting a message from both devices is not the same as it never having been delivered.

People who want a fast messenger with very large groups, big files and multi-device sync, and who will read the encryption section rather than skim it. Anyone who needs end-to-end encryption to be the default should note that here it lives in Secret Chats, and should look at Signal instead.

The most feature-dense messenger reviewed here and the most careful about what it claims: everything is encrypted, and end-to-end encryption is a mode you choose. That is not a trick — the listing states both facts accurately — but it rewards slow reading, because "encrypted" is the word a skimmer takes away and it is not the word that matters for a private conversation. Groups of 200,000, files of 2 GB and true multi-device sync are real capability, and the free claim is unqualified; the cost is that the strongest protection is opt-in and a reader has to know to look for it.