Telegram is offering a new way to get a premium subscription: all you have to do is voluntarily provide your phone number to send one-time passwords (OTPs) to other users, The Verge reports.

Telegram has started offering Peer-to-Peer Login (P2PL) only on Android devices and only in certain (unknown) regions. By joining the program, the user authorizes Telegram to use the phone number to send up to 150 messages with OTP codes to other users who are logged into their accounts.

Every month, when the user’s phone number is used to send the minimum number of OTPs, they will receive a gift code for a monthly premium subscription.

This solution is not without its critics: the recipient will see the phone number when it is used to send an OTP. And if something unpleasant happens as a result of this, Telegram’s terms of use make it clear that the company will not be held responsible for it.

“Accordingly, you understand and agree that Telegram will not be liable for any inconvenience, harassment or harm resulting from unwanted, unauthorized or illegal actions undertaken by users who became aware of your phone number through P2PL,” reads the terms of use of Telegram.

Once the OTP has been sent, the recipient can simply text the number back. People who participate in the P2PL program are instructed not to write to OTP recipients, even if they sent the message first. But Telegram has no way to enforce this requirement, no way to prevent people from replying to OTP messages.