Question 1
What messengers are best to use on Mobi for calls and correspondence? What data security advantage does Mobi have over a regular smartphone when it comes to messaging apps?
Short answer: The lowest risk of access to your data is when communication takes place on a Mobi smartphone in a messenger on the blockchain.
Other communication options—standard messengers such as Telegram, WhatsApp, and regular smartphone text messaging, access to communication data is obtained to varying degrees by big tech companies: Google, the instant messenger companies, and telecom operators.
Access to data varies, but these services may put at risk data on (1) the identity of the person communicating, (2) the identity of the second person communicating, (3) the date and time of communication, (4) the content of communication.
Detailed answer:
Standard messengers are centralized, meaning that they have specific servers on which all correspondence is stored. These include many popular messengers, such as Telegram, WhatsApp, VK, OK, etc. There are also decentralized messengers that use the blockchain instead of centralized servers, and some messengers have end-to-end encryption, the keys to which only you have.
Communication in standard instant messengers on a regular smartphone
Centralized messengers such as WhatsApp, Telegram, VK, OK, etc. involve three additional parties in every conversation on a regular smartphone: (a) the American tech company Google, through its Android operating system installed on the phone, (b) the messenger company, for example WhatsApp or Telegram, and (c) a telecom operator—the cellular or other internet provider.
Big tech companies—Google and the messenger company—have access to the largest volume of personal data of the communicating parties. In particular, Google may have access to data about (1) the identity of the person communicating (since both the phone and Android must be logged in), (2) the identity of the second person communicating (through contacts in the phone to which Android has access), and (3) the date and time of communication. Furthermore, the keyboard developer company may have access to (4) the content of the communication. This is usually also Google, but there are other keyboards, such as Microsoft's SwiftKey. Such keyboards may contain trackers that collect and transmit input data to the company that developed the keyboard.
Regarding voice conversations in messengers, audio recordings cannot typically be made, since this requires separate software compatible with the phone, the installation of which requires the user’s consent.
The messenger company has access to a comparable volume of personal data. By linking an account to the phone number and contacts in the messenger’s contact book, the messenger company has access to data about (1) the identity of the person communicating, (2) the identity of the second person communicating, and (3) the date and time communication. As all messenger companies claim, they do not have access to (4) the content of the communication, because communication is encrypted with end-to-end encryption, that is, encryption in which the keys to decryption are only on the user’s smartphone and not the messenger company.
But it should be noted that although the messenger company does not have the keys, the encryption algorithm was developed by the messenger company and the content of all messages is stored on company servers.
The telecom operator has access to a smaller amount of personal data. This is the cellular or WiFi internet provider. The telecom operator has access to data about (1) the identity of the person communicating (since the SIM card or WiFi is tied to the identity of its owner), and (3) the date and time of communication, but does not have access to data about (2) the identity of the person to whom the message was sent or (4) the content of the communication (other than the amount of data transferred).
Communication in standard instant messengers on a Mobi smartphone
The main advantage of the Mobi smartphone is that it completely deprives Google of the ability to have access to any data regarding communication. Google does not have access to data about (1) the identity of the person communicating, nor (2) the identity of the person with whom they are communicating, nor (3) the date, time of communication, nor (4) the content of the communication.
The messenger company still has access to data about (1) the identity of the person communicating and (3) the date and time of communication. This access is eliminated only if communication on the Mobi smartphone is carried out using a decentralized messenger.
Communication in decentralized (that is, on the blockchain) messengers on the Mobi smartphone
In this case, Google still has no access to anything regarding communication, and the messenger on the blockchain only has a record of the date and time of communication, but no information about any party involved or the content of the communication.
For clarity, see the two illustrations below: