Until the brush to a South Korean elder brother let a person immediately bright news, I was amused.
Coincidentally, let’s not patronize foreigners:
Apart from making me laugh and cry, these two pieces of news also brought me a bit of inspiration.
In fact, since the outbreak of the epidemic, I have been thinking about a question at home because I do not have to go out to visit relatives and friends: what contribution can the blockchain industry make to the fight against the epidemic?
• The simplest is of course to donate money or goods directly, or even send someone to be a volunteer;
• Second, use blockchain technology to provide traceability and publicity services for relief materials and donations, so that all kinds of information becomes open and transparent;
• More far-reaching is to look to the future and adopt blockchain technology and decentralization to improve infectious disease surveillance and early warning networks and decision-making processes, so as to avoid heavy losses caused by concealing the epidemic in a few key central nodes.
However, all of these ideas have a common flaw: they’ve already been written about, and I’m embarrassed to repeat them.
The two elder brothers’ cases in the news brought a question into my view: how to screen potential infected people more effectively?
It is well known that in the absence of a cure or vaccine, the most effective way to fight an infectious disease is to stop its transmission. The following popular science weibo post clearly illustrates the significance of taking quarantine measures:
A is the person who has contact history in Wuhan, B is the person whom A contacts in public places, C is the person whom A knows and contacts, and D is the person at home. Among them, A and C are easy to be screened out and isolated for observation, but it is difficult to distinguish which people belong to B, especially B does not know that he is B.
In order to quickly screen out type B patients, information such as train carriages and flight numbers of confirmed patients has been disclosed, and many Internet companies have quickly launched a search service for confirmed patients.
Such co-ride query service undoubtedly provides a great help for identifying type B population, but its effect is still limited. Of course, the most obvious problem is that the scope of inquiry is very limited. It can only query whether you have contacted Type A people on long-distance public transport, and cannot cover the information of urban buses and subways, let alone stations, high-speed service areas, shopping malls, restaurants and even elevators and other places.
Better screening for type B patients requires information about the path of those who have been diagnosed. Either by the patient’s own initiative, or through other means to determine.
Active declaration will inevitably be covered up. On the one hand, it is hard to ensure that everyone is willing to hand over private information. On the other hand, human memory is not particularly reliable, especially when it comes to trivial matters.
Since the active declaration is not accurate enough, can we use the existing technical means to solve it? In theory, it is not difficult to determine the movements of an ordinary person if you combine all the data from surveillance cameras, telecom operators, credit cards, Alipay and so on. For example, the Korean brother in the news was easily “sold” by credit card records.
However, in practice, it is very difficult to integrate the data of various companies and departments, which involves complex cross-regional and cross-department coordination and massive data retrieval, and is difficult to use on a large scale. Now, for example, tens of thousands of people who have been in contact with Wuhan are in China and around the world. Every day, thousands of new confirmed cases are reported. Even if the data are available, it is impossible to analyze them.
And, aside from the technical difficulties, there are huge legal and ethical risks in bringing everyone’s private data together. We don’t want our every move to be monitored and recorded, and we don’t want to run the risk of our private information being abused. Fighting infectious diseases is not enough to make people willing to give up their right to privacy.
So, can technology be used to protect personal privacy and encourage people to voluntarily report their path information, so as to improve the efficiency and accuracy of screening? Blockchain and cryptography may solve this problem.
There are many techniques used to protect privacy in cryptography. This scenario can use Private Set Intersection (PSI) in cryptography.
The problem description of “private set intersection” can be abstracted as two people, Alice and Bob, each have a set, and they want to calculate the intersection (or the size of the intersection) of the two sets without telling each other the contents of the set. At present, there are many mature solutions to PSI, including pure software solutions based on cryptography protocol, and hardware solutions based on SGX and other security chips. For the sake of space, I will not repeat it here.
Illustrations are from OSU’s Peter Rindal’s Slides
In apps that screen the travel intersection of confirmed patients, each element in the user set records which public places the user has been to at what time. Assuming that Alice is A type A person mentioned above, another user Bob can judge whether he has ever contacted Alice in public places according to the size of his intersection with Alice’s private set, thus realizing the function of screening Type B people without disclosing the private information of confirmed patients.
But cryptography only addresses the problem of matching historical travel data if it is available, and does not urge users to actively record that information — even if all private data is stored locally on their phones, rather than being uploaded to a server. If you can’t inspire users to record their travel information enthusiasm, then better than technology can’t finally get rid of the difficult situation of a clever housewife without rice.
The question of how to motivate users really bothered me for a while, until a colleague came up with an idea that hit me: suspected patients who could provide evidence of contact with confirmed patients would be given priority for testing and treatment.
In the face of large-scale outbreaks, the shortage of medical resources is an unavoidable reality. Especially in the early stages of this outbreak, when we don’t know enough about it, the ability to test for confirmation is not keeping pace with the spread of the virus. Many suspected patients could not receive nucleic acid test in time, and many of them did not even have the chance to be labeled as suspected patients, which is very detrimental to saving the lives of individual patients and isolating contacts as soon as possible to control the epidemic.
On the other hand, many patients with a common cold who are not infected with COVID-19 are also eager to be tested in the first place, out of fear. After all, you never know for sure until you get tested for a common cold.
What is the most efficient and rational way to allocate limited medical resources? A natural idea would be to give priority to those who have had contact with Wuhan or confirmed patients. But this gives patients in line an incentive to lie about their contact history in order to get attention and priority services, especially when suspected and confirmed patients can get free care. It would be much more convincing to have a piece of evidence to prove that he or she crossed paths with the confirmed patient.
Of course, since self-reports can be faked, so can the history recorded on mobile phones. Even if the technical threshold is slightly higher, there are bound to be national wealth seekers offering fake itineraries. This kind of last-minute writing is not only disruptive, but also discourages other users from recording truthfully, which is something we need to eliminate.
This is where blockchain comes in.
As we all know, blockchain is immutable, which is the Nemesis of any illegal modification. Therefore, we only need to adopt the idea of blockchain to fix the user’s travel information, so as to avoid the risk of forgery or tampering in the future. In this way, there is evidence of blockchain preservation and support, and its credibility has risen to a higher level. If a patient is identified with a history of travel, their travel information can be used for further screening, directly contributing to the control of the spread of the disease.
In this way, by combining privacy computing technology and blockchain technology, we are expected to expand the existing “confirmed patient co-query” to a larger range and finer granularity, greatly improving the efficiency and accuracy of screening type B contacts, and contributing to more precise and rapid control of the epidemic.
At the end: The above is only a technical idea that will most likely not catch up with the fight against COVID-19. Faced with problems in the real world, “pure technology” solutions are often very weak, because it is ultimately “people” who play a decisive role. China’s top virus research laboratory and the infectious disease surveillance and early warning network built because of SARS failed to play their due role in this outbreak. However, there is no need to be overly pessimistic, because “technology” is just a tool or weapon, only in the right hands can exert its original power. The Huoshenshan Hospital, completed in 10 days, is a testament to how powerful technology can be in the right hands.
If there is the next outbreak, hopefully we have block chain + privacy computing blessing trip intersection technology can assign the query system, block chain logistics traceability and tracking system, based on contributions and donations of block chain management system, etc, deployed more hope at that time, the people can give full play to the power of these new technologies and systems, Nip the epidemic in the bud before most people notice it.
