Privacy On Ncell App

Q: What data of mine are stored in the database?

The first thing that is stored in the database is your user ID used for your identification. If you register a number, the SHA-512 hash of the phone number is stored in the database instead of plain text. And, the token of the phone number is stored. However, the token contains your phone number, access token, and refresh token. Further, you can also encrypt your token for security.

The other thing that is stored in the database is some temporary variable that is essential for the bot to operate. The temporary variables don't contain any sensitive information and get deleted once a process is completed or canceled. This means they are only stored for an instant.

Q: How does encryption work in Ncell Bot?

When you encrypt your account, the bot will generate 1024-bit RSA key pairs (Public and Private keys). Then, you will be asked for an encryption passphrase that will be used to encrypt your private key with the AES 128-bit algorithm. Your public key and encrypted private key will be stored in the database along with the SHA hash of your encryption passphrase. Any existing accounts or new accounts will be encrypted with your public key.

When your accounts are encrypted, you need to unlock them before using any Ncell services.

Q: How does unlocking account works?

It's simple. You will be asked for your encryption passphrase. If the passphrase is correct, the bot will pin the passphrase in the chat. And every time you use the service, the bot will first fetch the passphrase from the pinned message then decrypt your private key. The decrypted private key is never stored in the database. Again, the decrypted private key will be used to decrypt your Ncell token.

You can unpin the passphrase message which will unpin the message only for you, not the bot. You can lock your account any time. Doing so will unpin the passphrase for the bot as well. So, the bot can't decrypt your private key and your account.

P.S. If you have a better idea of encrypting and decrypting the tokens, feel free to mention it on our group chat. I will appreciate it.

Q: As a bot owner, can't you hijack my encryption passphrase?

No, at least not in a simple way. If I simply create another instance of the bot to hijack your passphrase, I get the following error instead of your passphrase:

ERROR - TeleBot: "A request to the Telegram API was unsuccessful. Error code: 409. Description: Conflict: terminated by other getUpdates request; make sure that only one bot instance is running

So, to hijack your encryption passphrase, first I need need to stop the main bot, create a new evil instance of the bot and hijack your passphrase from the pinned message.

I would not go through all these efforts just to see your phone number or your account balance. Never, unless I have a crush on you.

And the additional activities like balance transfer, viewing call history or any other sensitive data can never be performed. Because these processes require an OTP pin which will be sent to your phone at that instant.

If you still doubt your account privacy, the best you can do is host the bot on your own server. Ping me, I will be happy to help you deploy the bot if necessary.

Q: Can a bot owner see the chat history?

I don't think a bot owner can see the chat history unless the conversations are logged into a database. In our case, the conversation is never logged. The bot is open-sourced and you are free to see the source code.