Telegram uses encryption, although not as extensively as some platforms. Unlike its competitor Signal, Telegram doesn't by default apply end-to-end encryption to messages, which prevents any message intercepted by a third party from being interpretable.

Are Telegram calls secure?

Most chats (Cloud chats) on Telegram are securely encrypted while in transit between your devices and Telegram's servers. ... Secret Chats should be as secure as MTProto, but users need to remember to turn them on. Voice calls are automatically E2E encrypted, likewise making them as secure as MTProto allows.

Are Telegram voice calls encrypted?

(Voice calls and video calls are end-to-end encrypted by default, the company says). But it's only messaging within Secret Chats where end-to-end encryption is available.