Since the outbreak of the epidemic, in order to deal with the epidemic, we have mobilized a lot of black technology. In particular, the "itinerary code", which is the most representative anti-epidemic black technology, specifically:
From March 13, 2020, the China Academy of Information and Communications Technology, together with the three basic telecom operators of China Mobile, China Unicom and China Telecom, will obtain the "signaling data" of mobile phones through the location of the base station where the user's mobile phone is located, providing free inquiry services for 1.6 billion mobile phone users across the country. Through this service, mobile phone users can find information about all the prefectures and cities they have visited in the previous 14 days.
Here's more to explain, 1.6 billion mobile phone users does not mean that there are 1.6 billion people, because many people actually own 2 or more mobile phones.
Once the itinerary code was launched, it was widely used, and as of March 25, 2020, the cumulative number of queries had exceeded 450 million.
Later, this black technology and health code became the most commonly used travel tool since the outbreak of the epidemic. According to the China News Network, as of January 2022, the Ministry of Industry and Information Technology said:
The communication itinerary card has been queried more than 25 billion times.
It can be said that it has been widely used and has become an indispensable part of our fight against the epidemic. So the question is, why can the itinerary code know where the code holder has been? What exactly is the principle? Legend has it that it can still be located after the shutdown and card is pulled, is this a rumor, or is it a fact?
The principle of communication trip big data card
The itinerary code, the full name is: communication trip big data card, its technical principle is actually to analyze the "mobile phone signaling data". So the question is, what is mobile phone signaling data?
When we usually call, send messages, and surf the Internet, in order to build a language path and data path between any two users in the telecommunications network, the relevant communication base station must carry out the corresponding word relay work, and send the result of the connection or further requirements to another related communication base station or user in the form of information.
In this process, the mobile phone / communication base station must jointly follow certain protocols and protocols, these protocols or protocols are called signaling methods.
Signaling information refers to the control instructions in the letter system, that is, the user in the use of mobile phones, in addition to calling, sending information and surfing the Internet, there is also a need for relevant signals to inform the base station and how the mobile phone communicates, to put it bluntly, it is a kind of instruction used to establish a temporary communication channel between the terminals, and maintain the normal operation of the network itself, equivalent to the nervous system of the information network.
And because everyone has begun to use mobile phones universally, therefore, telephone communication between people, people using mobile phones to access the Internet, and sending messages all need to be transmitted through base stations. Mobile phone transmitters and receivers, the same base station also have, these base stations and mobile phone terminals together constitute a communication network, which allows the base station to obtain the signaling information data of the mobile phone.
After the base station obtains these data, it can determine the location of the user based on the information of the data.
This means that if your mobile phone and communication base station have passed information, the base station will judge your specific location through the signaling information data in the message.
Generally speaking, if a mobile phone user has visited and stayed for 4 hours in the past 14 days, the communication itinerary big data card can provide free certification services for them.
The specific accuracy reaches the municipal level, and if it is overseas, it will also show the country and region (international), but the specific township will not be recorded.
So, it's not that you're going to be recorded as long as you pass through a place, it's actually a "full 4 hours" premise.
If you are driving from one city to another, as long as you do not stay in any one city for more than 4 hours in the middle, the itinerary card will not have a way to the area.
Since the three major operators have joined the "communication trip big data card" project this time, this means that as long as the three major operators set up the base station area, they can actually be identified, which means that this trip code is easy to use in all of China.
However, because the base station relied on for judgment, it will lead to a special situation, because the communication service usually has to take care of the communication continuity, to achieve no blind area coverage, which leads to the intersection of the administrative and administrative division of the two base station signals may be cross-coverage, resulting in the deviation of the result, the use of other proof can be adjusted accordingly.
The itinerary code is marked with four colors: green, yellow, orange, and red, and this color rule is dynamically changing.
The current rules are:
Red represents: confirmed or suspected patients with new crown pneumonia (data source: Health Commission);
The orange card represents: a close contact of a confirmed or suspected COVID-19 patient;
The yellow card represents: returning home from an overseas risk country within 14 days;
If there is an epidemic in your city and there is a medium-risk or high-risk area, the itinerary card will not change color, but will be represented by a "*".
Airplane mode, card pull, shutdown
These functions of the itinerary code are based on the normal use of the mobile phone. So the question is, if you put the phone in airplane mode, dial the card or shut down, is the itinerary code still valid?
The essence of this problem is actually: whether the mobile phone and the base station have carried out the transmission of "mobile phone signaling data", to put it bluntly, as long as the mobile phone can exchange data with the base station, it means that the itinerary code can continue to provide services.
Whether it is to turn off the traffic, put the card or be in airplane mode, it is not difficult to find that the mobile phone can make a temporary emergency call, or even a mobile phone that has just been bought, even if you do not insert the card, it does not mean that the mobile phone does not have information transmission with the base station.
Not only that, in order to stabilize the signal, the mobile phone has a large number of antennas built into it, all in order to take the initiative to find the base station as much as possible and keep in touch, rather than saying that it will start to find the base station when you want to call.
In other words, whenever you turn on your phone, whether it's airplane mode or card pulling, the itinerary code can actually provide free service.
If it is turned off, at this time, the mobile phone and the base station should completely disconnect the information transmission, so there will be no transmission of "mobile phone signaling data", then the travel code cannot provide positioning services at this time. At this point, if you locate your phone, the location of your phone is actually where you shut down.
However, the mobile phone industry has been committed to: mobile phone anti-loss, are trying to achieve the key can still be positioned.
In the Android mobile phone camp, mainstream mobile phone manufacturers can now provide cloud services, including mobile phone positioning, but this service still needs to be located through wireless networks for the time being. Therefore, after the shutdown, the displayed positioning is still at the time of shutdown.
Apple's situation and the Android camp is a little different, its mobile phone built-in Find My function, early in the mobile phone disconnection, you can use Bluetooth low energy to achieve positioning, mainly backed by huge shipments and a comprehensive product lineup.
Later, after Apple's iOS 15 was launched, a special feature was introduced: shutdown can also be located.
According to Apple's official introduction, this feature relies on a special processor: Always-on Processor (AOP). When you shut down, apple phones are not completely powered off, but with very little power to maintain the AOP processor. Many programs run separately through the AOP processor. If you turn off your iPhone, an option will pop up to let you choose whether to enable the Find My feature.
If you choose to enable, after shutting down, Find My can run through the AOP processor, which is essentially AOP will control the Bluetooth chip to work. Therefore, at this time, the Apple mobile phone is not directly back to the network, but relies on Bluetooth to automatically and the nearby iPhone through Bluetooth, NFC and even ultra-broadband communication to locate themselves back to the network.
So the question is, can this make the itinerary code recognizable?
According to the information released by Apple, it should not be. Therefore, after the introduction of this feature, many people expressed concerns about their privacy.
As a result, Apple officials later released some security measures and claimed that this security function can prevent others from tracking user information.