The gold standard of encryption, known as end-to-end encryption, where only the sender and person who receives the message are able to see it, is available on Telegram only when the Secret Chat function is enabled. Voice and video calls are also completely encrypted. Telegram users are able to send files of any type up to 2GB each and access them from any device, with no limit on cloud storage, which has made downloading files more popular on the platform. Messages are not fully encrypted by default. That means the company could, in theory, access the content of the messages, or be forced to hand over the data at the request of a government. But because group chats and the channel features are not end-to-end encrypted, Galperin said user privacy is potentially under threat. Although some channels have been removed, the curation process is considered opaque and insufficient by analysts.
from ms