Telegram provides end-to-end encrypted calls and optional end-to-end encrypted "secret" chats between two online users on smartphone clients, whereas cloud chats use client-server/ server-client encryption.

The transmission of messages to Telegram Messenger LLP servers is encrypted with the service's MTProto protocol. According to Telegram's privacy policy, "all data is stored heavily encrypted and the encryption keys in each case are stored in several other data centers in different jurisdictions. This way local engineers or physical intruders cannot get access to users' data".

They may also use automated algorithms to analyze messages in cloud chats to stop spam and phishing.

In their Privacy Policy, Telegram states the following about monitoring issues in content:

• For private messages, it’s up to the receiver to decide if content is unwelcomed. It could be a simple ‘hello’ being reported, which leads to you being blocked temporarily.
• As a general rule, people do mind getting unsolicited advertisements, links, invite links to groups or channels, random photos and, above all, anything related to commerce or online popularity. If you send them something like this, you will be blocked.

Unspoken rules:

Many reasons can lead to a telegram report, and sending spam and harassment messages to other users is just one example. In general, the main reasons that may lead to the ban of telegram users are mentioned in below: