How Are Secret Chats Different?
Secret chats are designed for those who demand a higher level of privacy than ordinary chats. All messages in secret chats are secured with end-to-end encryption, meaning only you and the recipient can read them—no one else, not even Telegram, can decrypt them. Additionally, messages cannot be forwarded from secret chats, and when you delete a message on your end, it will also be deleted on the recipient's device.
You can also set messages, photos, videos, and files to self-destruct after a certain time once they've been read or opened. The message will then vanish from both devices.
Secret chats are device-specific and not stored in the Telegram cloud. This means you can only access them from the device where they were created. They remain secure as long as your device is safe.
How Do I Start a Secret Chat?
To start a secret chat, open the profile of the person you want to contact, tap on '…', and then select 'Start Secret Chat'. Keep in mind that Telegram secret chats are tied to a specific device. If you start a secret chat on one device, it won't appear on your other devices. If you log out, you will lose all your secret chats. You can create multiple secret chats with the same contact.
How Do Self-Destructing Messages Work?
The Self-Destruct Timer is available for all messages in Secret Chats and for media in private cloud chats. To set the timer, tap the clock icon (on iOS, in the input field; on Android, in the top bar) and choose the desired time limit. The timer starts when the message is displayed on the recipient's screen (indicated by two check marks). When the time runs out, the message disappears from both devices. We will attempt to notify you if a screenshot is taken.
Note that the timer in Secret Chats only applies to messages sent after the timer is set; earlier messages are not affected.
Can I Be Certain That My Conversation Partner Doesn't Take a Screenshot?
Unfortunately, it's impossible to guarantee screenshot detection on some systems, especially certain Android and Windows Phone devices. We do our best to alert you about screenshots in Secret Chats, but it's still possible for someone to bypass these notifications and capture a screenshot unnoticed. We recommend sharing sensitive information only with people you trust. Ultimately, someone could always photograph the screen with another device or an old-school camera.
What Is This 'Encryption Key' Thing?
When a secret chat is created, the devices exchange encryption keys using the Diffie-Hellman key exchange. Once the secure connection is established, we generate an image that visualizes the encryption key. You can compare this image with the one your friend sees—if they match, your secret chat is secure, and no man-in-the-middle attack can succeed.
In newer Telegram versions, both participants using updated apps will see a larger image along with a textual representation of the key (this is not the key itself). Always compare visualizations through a channel you know is secure, ideally in person during an offline meeting.
Why Not Make All Chats 'Secret'?
All Telegram messages are always encrypted. Secret Chats use client-client encryption, while Cloud Chats use client-server/server-client encryption and are stored encrypted in the Telegram Cloud. This allows your cloud messages to be secure and immediately accessible from any device, even if you lose one. Secret chats sacrifice some convenience for maximum security.