zero-click attacks

Zero-click attacks: spying in the smartphone era

Zero-click attacks exploit security breaches in smartphones in order to hack into a target’s device without the target having to do anything. They are now a threat to everyone, from governments to medium-sized companies.

“Zero-click attacks are not a new phenomenon”, says Hervé Debar, a researcher in cybersecurity at Télécom SudParis. “In 1988 the first computer worm, named the “Morris worm” after its creator, infected 6,000 computers in the USA (10% of the internet at the time) without any human intervention, causing damage estimated at several million dollars.” By connecting to messenger servers which were open access by necessity, this program exploited weaknesses in server software, infecting it. It could be argued that this was one of the very first zero-click attacks, a type of attack which exploits security breaches in target devices without the victim having to do anything.

There are two reasons why this type of attack is now so easy to carry out on smartphones. Firstly, the protective mechanisms for these devices are not as effective as those on computers. Secondly, more complex processes are required in order to present videos and images, meaning that the codes enabling such content to be displayed are often more complex than those on computers. This makes it easier for attackers to hack in and exploit security breaches in order to spread malware. As Hervé Debar explains, “attackers must, however, know certain information about their target – such as their mobile number or their IP address – in order to identify their phone. This is a targeted type of attack which is difficult to deploy on a larger scale as this would require collecting data on many users.”

Zero-click attacks tend to follow the same pattern: the attacker sends a message to their target containing specific content which is received in an app. This may be a sound file, an image, a video, a gif or a pdf file containing malware. Once the message has been received, the recipient’s phone processes it using apps to display the content without the user having to click on it. While these applications are running, the attacker exploits breaches in their code in order to run programs resulting in spy software being installed on the target device, without the victim knowing.

Zero-days: vulnerabilities with economic and political impact

Breaches exploited in zero-click attacks are known as “zero-days”, vulnerabilities which are unknown to the manufacturer or which have yet to be corrected. There is now a global market for the detection of these vulnerabilities: the zero-day market, which is made up of companies looking for hackers to identify these breaches. Once the breach has been identified, the hacker will produce a document explaining it in detail, with the company who commissioned the document often paying several thousand dollars to get their hands on it. In some cases the manufacturer themselves might buy such a document in an attempt to rectify the breach. But it may also be bought by another company looking to sell the breach to their clients – often governments – for espionage purposes. According to Hervé Debar, between 100 and 1,000 vulnerabilities are detected on devices each year. 

Zero-click attacks are regularly carried out for theft or espionage purposes. For theft, the aim may be to validate a payment made by the victim in order to divert their money. For espionage, the goal might be to recover sensitive data about a specific individual. The most recent example was the Pegasus affair, which affected around 50,000 potential victims, including politicians and media figures. “These attacks may be a way of uncovering secret information about industrial, economic or political projects. Whoever is responsible is able to conceal themselves and to make it difficult to identify the origin of the attack, which is why they’re so dangerous”, stresses Hervé Debar. But it is not only governments and multinationals who are affected by this sort of attack – small and medium-sized companies are too. They are particularly vulnerable in that, owing to a lack of financial resources, they don’t have IT professionals running their systems, unlike major organisations.

Also read on I’MTech Cybersecurity: high costs for companies

More secure computer languages

But there are things that can be done to limit the risk of such attacks affecting you. According to Hervé Debar, “the first thing to do is use your common sense. Too many people fall into the trap of opening suspicious messages.” Personal phones should also be kept separate from work phones, as this prevents attackers from gaining access to all of a victim’s data. Another handy tip is to back up your files onto an external hard drive. “By transferring your data onto an external hard drive, it won’t only be available on the network. In the event of an attack, you will safely be able to recover your data, provided you disconnected the disc after backing up.” To protect against attacks, organisations may also choose to set up intrusion detection systems (IDS) or intrusion prevention systems (IPS) in order to monitor flows of data and access to information.

In the fight against cyber-attacks, researchers have developed alternative computing languages. Ada, a programming language which dates back to the 1980s, is now used in the aeronautic industry, in railways and in aviation safety. For the past ten years or so the computing language Rust has been used to solve problems linked to the management of buffer memory which were often encountered with C and C++, languages widely used in the development of operating systems. “These new languages are better controlled than traditional programming languages. They feature automatic protective mechanisms to prevent errors committed by programmers, eliminating certain breaches and certain types of attack.” However, “writing programs takes time, requiring significant financial investment on the part of companies, which they aren’t always willing to provide. This can result in programming errors leading to breaches which can be exploited by malicious individuals or organisations.”

Rémy Fauvel

livreurs de plateformes

Delivery riders seeking social protection

Cynthia Srnec, Sciences Po and Cédric Gossart, Institut Mines-Télécom Business School

“In the ideal world of the delivery platforms, we would say nothing, just smile politely, “Hello, sir”, “Goodbye”, get on our bikes, make our deliveries, never fall, never have an accident, never make a complaint […]. We used to pay you €5, now it’s €2.60, what are you going to do about it? On you go, chop chop! Make sure the food stays hot, ignore red lights, and don’t die please!”

This testimony from a young delivery rider illustrates the subordination that is central to an ecosystem in which algorithms call all the shots.

What needs to be done for these workers, exposed to various different risks? What do they need in terms of social protection?

These questions are very much central to the debate around the planned finance law for social security for 2022. First proposed back in September, its aim is to improve social protection for self-employed workers, but the improvements put forward don’t seem to factor in the mishaps which can befall delivery riders.

We asked them about their needs and the difficulties they face via an online questionnaire. 219 delivery drivers active in France during the pandemic responded, 15 of whom were interviewed.

The delivery riders who responded to our questionnaire are young (3 out of 4 are under 30 years of age) and don’t earn very much: half of them make less than €900/month before tax. Although half are logged on between 20 and 40 hours a week, they don’t get paid for time spent waiting on orders, which prevents many of them from taking on another job (for 60% of them, this is their only source of work). Before working as delivery riders, 37% were unemployed, this group most likely to have done this work for more than 3 years.

Their preferred mode of transport is push bike (37%) followed by electric bike (26%). Riders on push bikes earn less than the others (22% earn less than €900/month), while the majority of delivery riders who use another mode of transport earn slightly more.

The risks of the job

“I was hit by a pedestrian and broke my hand. I didn’t realise I had broken anything, and so I kept working. […] there are a lot of delivery riders […] who keep working with broken bones because they have to for financial reasons, or because they don’t have any social security allowing them to take time off to recover.” (Interview n°3)

This account illustrates the physical and financial vulnerability which affects many delivery riders. Only 31% of them have never experienced health difficulties as a result of their work. 70% have issues with traffic and parking, 61% have significant issues because of time spent waiting to be allocated a route, and 68% have significant issues because of time spent waiting for orders to be prepared. We don’t know exactly how many accidents have befallen riders or how many have died, but the delivery rider community is starting to come together to take action.

Are delivery riders treated properly?

The vulnerability of delivery riders depends on the risks they are exposed to and what protections they have in place (e.g. a salary, family health insurance, etc.).

According to our survey, the most vulnerable delivery riders (V4) are the most exposed and have the least protection (the unemployed, illegal immigrants, long-term delivery riders, etc.). These highly vulnerable delivery riders are part of the 32% who told us they did not have any social security coverage, and aren’t aware of all of their rights (25% of delivery riders who responded to our questionnaire didn’t know if they had any social security coverage). They generally don’t inform their employer if they have any issues (57% didn’t make the company aware about accident or illness). Among those who did, 61% were given no assistance, and what was on offer didn’t compensate for the lack of income as a result of them being off work:

“There’s no point. I knew full well that the self-employment benefits would cover nothing or practically nothing. I knew that the top-up health coverage policies with the platforms are very low-cost contracts, even extremely low-cost, and I knew there would be no point making a claim.” (Interview n°2)

A “dirty job”

The variable geometry of the vulnerability of workers doing this “dirty job” have to face is down in no small part to the “paltry” social protection they get.

This legal and institutional void benefits platforms, some of whom have been taken to court for off-the-books work.

In Spain the law was changed in August 2021 to make it that every delivery rider is considered an employee. This resolution to the precarity brought about through the gig-economy, a pressing social issue of our times, has support in France from unions and collectives of delivery riders, but also from the EU Parliament:

“The coverage, suitability and formal and effective transparency of social protection must apply to all workers, including the self-employed.”

Bear in mind that 97% of the delivery riders who responded to our questionnaire were registered self-employed.

Morgane Le Guern from the MGEN Corporate Foundation for Public Health contributed to this article.

Cynthia Srnec, postdoctoral researcher, Sciences Po and Cédric Gossart, Professor (permanent, full-time), Institut Mines-Télécom Business School

This article has been republished from The Conversation under a Creative Commons licence. Read the original article.


Facebook: a small update causes major disruption

Hervé Debar, Télécom SudParis – Institut Mines-Télécom

Late on October 4, many users of Facebook, Instagram and WhatsApp were unable to access their accounts. All of these platforms belong to the company Facebook and were all affected by the same type of error: an accidental and erroneous update to the routing information for Facebook’s servers.

The internet employs various different types of technology, two of which were involved in yesterday’s incident: BGP (border gateway protocol) and DNS (domain name system).

In order to communicate, each machine must have an IP address. Online communication involves linking two IP addresses together. The contents of each communication are broken down into packets, which are exchanged by the network between a source and a destination.

How BGP (border gateway protocol) works

The internet is comprised of dozens of “autonomous systems”, or AS, some very large, and others very small. Some AS are interconnected via exchange points, enabling them to exchange data. Each of these systems is comprised of a network of routers, which are connected using either optical or electrical communication links. Communication online circulates using these links, with routers responsible for transferring communications between links in accordance with routing rules. Each AS is connected to at least one other AS, and often several at once.

When a user connects their machine to the internet, they generally do so via an internet service provider or ISP. These ISPs are themselves “autonomous systems”, with address ranges which they allocate to each of their clients’ machines. Each router receiving a packet will analyse both the source and the destination address before deciding to transfer the packet to the next link, following their routing rules.

In order to populate these routing rules, each autonomous system shares information with other autonomous systems describing how to associate a range of addresses in their possession with an autonomous system path. This is done step by step through the use of the BGP or border gateway protocol, ensuring each router has the information it needs to transfer a packet.

DNS (domain name system)

The domain name system was devised in response to concerns surrounding the lack of transparency with IP addresses for end users. For available servers on the internet, this links “” with the IP address “”.

Each holder of a domain name sets up (or delegates) a DNS server, which links domain names to IP addresses. They are considered to be the most reliable source (or authority) for DNS information, but are also often the first cause of an outage – if the machine is unable to resolve a name (i.e. to connect the name requested by the user to an address), then the end user will be sent an error message.

Each major internet operator – not just Facebook, but also Google, Netflix, Orange, OVH, etc. – has one or more autonomous systems and coordinates the respective BGP in conjunction with their peers. They also each have one or more DNS servers, which act as an authority over their domains.

The outage

Towards the end of the morning of October 4, Facebook made a modification to its BGP configuration which it then shared with the autonomous systems it is connected to. This modification resulted in all of the routes leading to Facebook disappearing, across the entire internet.

Ongoing communications with Facebook’s servers were interrupted as a result, as the deletion of the routes spread from one autonomous system to the next, since the routers were no longer able to transfer packets.

The most visible consequence for users was an interruption to the DNS and an error message, followed by the DNS servers of ISPs no longer being able to contact the Facebook authoritative server as a result of the BGP error.

This outage also caused major disruption on Facebook’s end as it rendered remote access and, therefore, teleworking, impossible. Because they had been using the same tools for communication, Facebook employees found themselves unable to communicate with each other, and so repairs had to be carried out at their data centres. With building security also online, access proved more complex than first thought.

Finally, with the domain name “” no longer referenced, it was identified as free by a number of specialist sites for the duration of the outage, and was even put up for auction.

Impact on users

Facebook users were unable to access any information for the duration of the outage. Facebook has become vitally important for many communities of users, with both professionals and students using it to communicate via private groups. During the outage, these users were unable to continue working as normal.

Facebook is also an identity provider for many online services, enabling “single sign-on”, which involves users reusing their Facebook accounts in order to access services offered by other platforms. Unable to access Facebook, users were forced to use other login details (which they may have forgotten) in order to gain access.

Throughout the outage, users continued to request access to Facebook, leading to an increase in the number of DNS requests made online and a temporary but very much visible overload of DNS activity worldwide.

This outage demonstrated the critical role played by online services in our daily lives, while also illustrating just how fragile these services still are and how difficult it can be to control them. As a consequence, we must now look for these services to be operated with the same level of professionalism and care as other critical services.

Banking, for example, now takes place almost entirely online. A breakdown like the one that affected Facebook is less likely to happen to a bank given the standards and regulations in place for banking, such as the Directive On Network And Service Securitythe General Data Protection Regulation or PCI-DSS.

In contrast, Facebook writes its own rules and is partially able to evade regulations such as the GDPR. Introducing service obligations for these major platforms could improve service quality. It is worth pointing out that no bank operates a network as impressive as Facebook’s infrastructure, the size of which exacerbates any operating errors.

More generally, after several years of research and standardisation, safety mechanisms for BGP and DNS are now being deployed, the aim being to prevent attacks which could have a similar impact. The deployment of these security mechanisms will need to be accelerated in order to make the internet more reliable.

Hervé Debar, Director of Research and PhDs, Deputy director, Télécom SudParis – Institut Mines-Télécom

This article has been republished from The Conversation under a Creative Commons licence. Read the original article.

Pharmaceutical industry

Caring for the population or one’s earnings? A dilemma for marketers in the pharmaceutical industry

Loréa Baïada-Hirèche, Institut Mines-Télécom Business School ; Anne Sachet-Milliat, ISC Paris Business School et Bénédicte Bourcier-Béquaert, ESSCA École de Management

The pharmaceutical industry is rocked by scandals on a regular basis. Oxycodon, for example, has been massively distributed in the United States despite being a highly addictive opioid analgesic, and has been implicated in some 200,000 deaths by overdose in the United States since 1999.

Closer to home, it took more than 15 years for Servier Laboratories’ Mediator to be withdrawn from the market, even though its prescription as an appetite suppressant, outside its initial therapeutic indication, caused numerous victims, including 2,000 recorded deaths. The outcome of the trial in March 2021 highlighted not only the responsibility of doctors, but also that of the laboratories producing these drugs, as was also the case for Levothyrox, manufactured by Merck.

These different scandals are merely the visible manifestation of the constant tension generated in this sector between the pursuit of profit and its fundamental health mission. The marketing professionals who are responsible for promoting medicines to patients and doctors seem particularly concerned by this ethical conflict which can cause them to question their real mission: is it treating or selling?

In the course of our research, we set out to discover how marketers in the pharmaceutical sector perceive this quandary and how they deal with it.

Economic interest but a health mission

The ethical conflicts encountered can lead marketers into situations of “moral dissonance”. This refers to occasions when people’s behaviors or decisions conflict with their moral values. Because it brings into play elements which are central to people’s identity such as their values, moral dissonance can generate significant psychological discomfort, giving rise to guilt and affecting self-esteem.

The people affected will then engage in strategies designed to reduce this state of dissonance, which are mainly based on the use of self-justification mechanisms but may also include changing their behavior or seeking social support.

To understand the attitudes of pharmaceutical marketing professionals, we conducted in-depth interviews with 18 of them, which revealed that these individuals are beset by ethical conflicts of varying severity, most of which relate to decisions that are of economic interest but lead to their failure to fulfill their health mission. This may involve potential harm to patients, infringements of regulations or breaches of professional ethics. Conflicts seem to affect people more intensely when the choices have major impacts on patients’ health.

The Servier affair – a turning point

Our series of interviews revealed that three strategies are employed in an effort to resolve this conflict. The first strategy is to minimize the ethically sensitive nature of the issue, which means burying one’s head in the sand, ignoring the conflict or forgetting about it as quickly as possible.

For example, one respondent explains:

“I wouldn’t say that pharmaceutical industry is whiter than white, either. There have been cases like Servier, of people who were dishonest. But that’s not the case for most people who work in the industry. They are happy to work in an industry that has made a positive contribution to society.”

According to these professionals, there is no conflict between the health and economic missions: making a profit is a way to finance medical research. This perspective makes pharmaceutical companies out to be “the main investors in health”.

In addition, they point out that their practices are very tightly regulated by law. Several respondents point out that Mediator was a landmark case:

“There is no longer a problem because everything has been regulated. Problems caused by conflicts of interest such as the Servier case are over, they can’t happen anymore. There truly was a before and after Mediator, it really changed things.”

Unable to ignore the media-driven attacks on the pharmaceutical industry, they defend themselves by denouncing the media’s role in stirring up controversy, the headlines that seek to “create a buzz” and the “journalists who don’t have anything better to write about”.

In contrast, other respondents are well aware of the risks that the marketed product poses to patients. However, they claim to be taking these risks precisely for patient’s sake. This is how the rationale for doubling the doses recommended under the regulations for children with serious pathologies is justified:

Like heroes

“Even if it’s a product that is dangerous, potentially dangerous, and on which you don’t have too much hindsight, you tell yourself that you can decide, with the chief scientist, to support the doctors doubling the doses because there’s a therapeutic benefit.”

The emphasis on acting in the patient’s interest is disturbing because it leads marketers to conceal the economic dimension of their activity and to present it as a secondary concern. However, doubling the doses does indeed increase the sales of the product.

Paradoxically, referring to the patient’s well-being in this way can actually serve to endorse unethical acts, while sometimes enabling the marketers to present themselves as heroes who work miracles for their patients. One of them justifies his actions in this way:

“Our product was very beneficial to patients; everyone was grateful to us… First there were the health professionals who told us ‘Our patients are delighted, their cholesterol levels are really low, it’s great’ and then there were the patients who testified that ‘My doctor had been forcing me to take cholesterol-lowering drugs for the past three years and I was always in pain everywhere… I’ve been taking your products for two months now and not only is my cholesterol level low, but above all, I’m no longer in any pain whatsoever.’”

Their way of presenting their profession sometimes even makes them out to be acting as caregivers.

In the final strategy, some respondents note that the notion of profitability takes precedence over the health mission, and express their mistrust of the discourse developed by other sales professionals:

“Money has become so important these days, and I get the impression there is hardly any concern for ethics in the organizations and people marketing the products.”

The disillusionment of these marketers is such that, in contrast to the cases mentioned above, they can no longer find arguments to justify their marketing actions and reduce their malaise.

“I was not very comfortable because I felt like I was selling something that could possibly hurt people or even be fatal in certain cases. I was feeling a little guilty actually… I was thinking that I would have preferred to have been marketing clothes, or at least untainted products.”

The only way out of their dissonance seems to be to avoid problematic practices by changing jobs, companies, or even leaving the pharmaceutical industry altogether.

Training and regulatory affairs

What is the solution? It seems difficult to make recommendations to pharmaceutical manufacturers in light of the doubts about the real willingness of top management to prevent unethical behavior by their employees when such behavior is adopted in their economic interest.

However, highlighting the existence of moral dissonance and the psychological suffering it inflicts upon workers should cause them concern. Studies show that these phenomena have negative consequences such as loss of commitment to work and increased staff turnover.

This is especially true in the pharmaceutical industry, which is involved in a noble cause – health – to which the respondents generally remain strongly attached.

Externally, an ethical dimension should be more systematically integrated into marketing training, especially in specialized health marketing courses.

Moreover, although the law has been tightened up, particularly after the Mediator affair, this has not prevented the emergence of new scandals, particularly in new markets such as implants. To protect citizens, the public authorities should therefore be paying more attention to para-medical products, which are currently subject to less restrictive regulations.

Loréa Baïada-Hirèche, Senior Lecturer in Human Resources Management, Institut Mines-Télécom Business School; Anne Sachet-Milliat, Lecturer and Researcher in Business Ethics, ISC Paris Business School and Bénédicte Bourcier-Béquaert, Lecturer and Researcher in Marketing, ESSCA École de Management

This article has been republished from The Conversation under a Creative Commons license. Read the original article (in French).

3D printing, a revolution for the construction industry?

Estelle Hynek, IMT Nord Europe – Institut Mines-Télécom

A two-story office building was “printed” in Dubai in 2019, becoming the largest 3D-printed building in the world by surface area: 640 square meters. In France, XtreeE plans to build five homes for rent by the end of 2021 as part of the Viliaprint project. Constructions 3D, with whom I am collaborating for my thesis, printed the walls of the pavilion for its future headquarters in only 28 hours.

Today, it is possible to print buildings. Thanks to its speed and the variety of architectural forms that it is capable of producing, 3D printing enables us to envisage a more economical and environmentally friendly construction sector.

3D printing consists in reproducing an object modeled on a computer by superimposing layers of material. Also known as “additive manufacturing”, this technique is developing worldwide in all fields, from plastics to medicine, and from food to construction.

For the 3D printing of buildings, the mortar – composed of cement, water and sand – flows through a nozzle connected to a pump via a hose. The sizes and types of printers vary from one manufacturer to another. The “Cartesian” printer (up/down, left/right, front/back) is one type, which is usually installed in a cage system on which the size of the printed elements is totally dependent. Another type of printer, such as the “maxi printer”, is equipped with a robotic arm and can be moved to any construction site for the direct in situ printing of different structural components in a wider range of object sizes.

L’attribut alt de cette image est vide, son nom de fichier est file-20210818-25-18klydg.jpg.
Pavilion printed by Constructions 3D in Bruay-sur-l’Escaut. Constructions 3D, provided by the author

Today, concrete 3D printing specialists are operating all over the world, including COBOD in Denmark, Apis Cor in Russia, XtreeE in France and Sika in Switzerland. All these companies share a common goal: promoting the widespread adoption of additive manufacturing for the construction of buildings.

From the laboratory to full scale

3D printing requires mortars with very specific characteristics that enable them to undergo rapid changes.

In fact, these materials are complex and their characterization is still under development: the mortars must be sufficiently fluid to be “pumpable” without clogging the pipe, and sufficiently “extrudable” to emerge from the printing nozzle without blocking it. Once deposited in the form of a bead, the behavior of the mortar must change very quickly to ensure that it can support its own weight as well as the weight of the layers that will be superimposed on it. No spreading or “structural buckling” of the material is permitted, as it could destroy the object. For example, a simple square shape is susceptible to buckling, which could cause the object to collapse, because there is no material to provide lateral support for the structure’s walls. Shapes composed of spirals and curves increase the stability of the object and thus reduce the risk of buckling.

These four criteria (pumpability, extrudability, constructability and aesthetics) define the specifications for cement-based 3D-printing “inks”. The method used to apply the mortar must not be detrimental to the service-related characteristics of the object such as mechanical strength or properties related to the durability of the mortar in question. Consequently, the printing system, compared to traditional mortar application methods, must not alter the performance of the material in terms of both its strength (under bending and compression) and its longevity.

In addition, the particle size and overall composition of the mortar must be adapted to the printing system. Some systems, such as that used for the “Maxi printer”, require all components of the mortar except for water to be in solid form. This means that the right additives (chemicals used to modify the behavior of the material) must then be found. Full-scale printing tests require the use of very large amounts of material.

Initially, small-scale tests of the mortars – also called inks – are carried out in the laboratory in order to reduce the quantities of materials used. A silicone sealant gun can be used to simulate the printing and enable the validation of several criteria. Less subjective tests can then be carried out to measure the “constructable” nature of the inks. These include the “fall cone” test, which is used to observe changes in the behavior of the mortar over time, using a cone that is sunk into the material at regular intervals.

Once the mortars have been validated in the laboratory, they must then undergo full-scale testing to verify the pumpability of the material and other printability-related criteria.

L’attribut alt de cette image est vide, son nom de fichier est file-20210818-27-13hdzxe.jpg.
Mini printer. Estelle Hynek, provided by the author

It should be noted that there are as yet no French or European standards defining the specific performance criteria for printable mortars. In addition, 3D-printed objects are not authorized for use as load-bearing elements of a building. This would require certification, as was the case for the Viliaprint project.

Finding replacements for the usual ingredients of mortar for more environmentally friendly and economical inks

Printable mortars are currently mainly composed of cement, a material that is well known for its significant contribution to CO₂ emissions. The key to obtaining more environmentally friendly and economical inks is to produce cement-based inks with a lower proportion of “clinker” (the main component of cement, obtained by the calcination of limestone and clay), in order to limit the carbon impact of mortars and their cost.

With this in mind, IMT Nord-Europe is working on incorporating industrial by-products and mineral additives into these mortars. Examples include “limestone filler”, a very fine limestone powder; “blast furnace slag”, a co-product of the steel industry; metakaolin, a calcinated clay (kaolinite); fly ash, derived from biomass (or from the combustion of powdered coal in the boilers of thermal power plants); non-hazardous waste incineration (NHWI) bottom ash, the residue left after the incineration of non-hazardous waste, or crushed and ground bricks. All of these materials have been used in order to partially or completely replace the binder, i.e. cement, in cement-based inks for 3D printing.

Substitute materials are also being considered for the granular “skeleton” structure of the mortar, usually composed of natural sand. For example, the European CIRMAP project is aiming to replace 100% of natural sand with recycled sand, usually made from crushed recycled concrete obtained from the deconstruction of buildings.

Numerous difficulties are associated with the substitution of the binder and granular skeleton: mineral additions can make the mortar more or less fluid than usual, which will impact the extrudable and constructable characteristics of the ink, and the mechanical strength under bending and/or compression may also be significantly affected depending on the nature of the material used and the cement component substitution rate.

Although 3D printing raises many issues, this new technology enables the creation of bold architectural statements and should reduce the risks present on today’s construction sites.

Estelle Hynek, PhD student in civil engineering at IMT Nord Europe – Institut Mines-Télécom

This article has been republished from The Conversation under a Creative Commons license. Read the original article (in French).

web browsing

How our Web browsing has changed in 30 years

Victor Charpenay, Mines Saint-Étienne – Institut Mines-Télécom

On August 5, 1991, a few months before I was born, Tim Berners-Lee unveiled his invention, called the “World Wide Web”, to the public and encouraged anyone who wanted to discover it to download the world’s very first prototype Web “browser”. This means that the Web as a public entity is now thirty years old.

Tim Berners-Lee extolled the simplicity with which the World Wide Web could be used to access any information using a single program: his browser. Thanks to hypertext links (now abbreviated to hyperlinks), navigation from one page to another was just a click away.

However, the principle, which was still a research topic at that time, seems to have been undermined over time. Thirty years later, the nature of our web browsing has changed: we are visiting fewer websites but spending more time on each individual site.

Hypertext in the past: exploration

One of the first scientific studies of our browsing behavior was conducted in 1998 and made a strong assumption: that hypertext browsing was mainly used to search for information on websites – in short, to explore the tree structure of websites by clicking. Search engines remained relatively inefficient, and Google Inc. had just been registered as a company. As recently as 2006 (according to another study published during the following year), it was found that search engines were only used to launch one in six browsing sessions, each of which then required an average of a dozen clicks.

L’attribut alt de cette image est vide, son nom de fichier est file-20210906-17-xeytzq.jpg.
Jade boat, China. Metropolitan Museum of Art,

Today, like most Internet users, your first instinct will doubtless be to “Google” what you are looking for, bypassing the (sometimes tedious) click-by-click search process. The first result of your search will often be the right one. Sometimes, Google will even display the information you are looking for directly on the results page, which means that there will be no more clicks and therefore no more need for hypertext browsing.

To measure this decline of hypertext from 1998 to today, I conducted my own (modest) analysis of browsing behavior, based on the browsing history of eight people over a two-month period (April-May 2021), who sent me their histories voluntarily (no code was hidden in their web pages, in contrast to the practices of other browsing analysis algorithms), and the names of the visited web sites were anonymized ( became *.com). Summarizing the recurrent patterns that emerged from these browsing histories shows not only the importance of search engines, but also the concentration of our browsing on a small number of sites.

Hypertext today: the cruise analogy

Not everyone uses the Web with the same intensity. Some of the histories analyzed came from people who spend the vast majority of their time in front of the screen (me, for example). These histories contain between 200 and 400 clicks per day, or one every 2-3 minutes for a 12-hour day. In comparison, people who use their browser for personal use only perform an average of 35 clicks per day. Based on a daily average of 2.5 hours of browsing, an Internet user clicks once every 4 minutes.

What is the breakdown of these clicks during a browsing session? One statistic seems to illustrate the persistence of hypertext in our habits: three quarters of the websites we visit are accessed by a single click on a hyperlink. More precisely, on average, only 23% of websites are “source” sites, originating from the home page, a bookmark or a browser suggestion.

However, the dynamics change when we analyze the number of page views per website. Indeed, most of the pages visited come from the same sites. On average, 83% of clicks take place within the same site. This figure remains relatively stable over the eight histories analyzed: the minimum is 73%, the maximum 89%. We typically jump from one Facebook page to another, or from one YouTube video to another.

There is therefore a dichotomy between “main” sites, on which we linger, and “secondary” sites, which we consult occasionally. There are very few main sites: ten at the most, which is barely 2% of all the websites a person visits. Most people in the analysis have only two main sites (perhaps Google and YouTube, according to the statistics of the most visited websites in France).

On this basis, we can paint a portrait of a typical hypertext browsing session, thirty years after the widespread adoption of this principle. A browsing session typically begins with a search engine, from which a multitude of websites can be accessed. We visit most of these sites once before leaving our search engine. We always visit the handful of main sites in our browsing session via our search engine, but once on a site, we carry out numerous activities on it before ending the session.

The diagram below summarizes the portrait I have just painted. The websites that initiate a browsing session are in yellow, the others in blue. By analogy with the exploratory browsing of the 90s, today’s browsing is more like a slow cruise on a select few platforms, most likely social platforms like YouTube and Facebook.

L’attribut alt de cette image est vide, son nom de fichier est file-20210831-23-1jlvak1.png.
A simplified graph of browsing behavior; the nodes of the graph represent a website (yellow for a site initiating a browsing session, blue for other sites) and the lines represent one or more clicks from one site toward another (the thickness of the lines is proportional to the number of clicks). Victor Charpenay, provided by the author.

The phenomenon that restricts our browsing to a handful of websites is not unique to the web. This is one of the many examples of Pareto’s law, which originally stated that the majority of the wealth produced was owned by a minority of individuals. This statistical law crops up in many socio-economic case studies.

However, what is interesting here is that this concentration phenomenon is intensifying. The 1998 study gave an average of 3 to 8 pages visited per website. The 2006 survey reported 3.4 page visits per site. The average I obtained in 2021 was 11 page visits per site.

Equip your navigator with a “porthole”

The principle of hypertext browsing is nowadays widely abused by the big Web platforms. The majority of hyperlinks between websites – as opposed to self-referencing links (those directed by websites back to themselves, shown in blue on the diagram above) – are no longer used by humans for browsing but by machines for automatically installing fragments of spyware code on our browsers.

There is a small community of researchers who still see the value of hypermedia on the web, especially when users are no longer humans, but bots or “autonomous agents” (which are programmed to explore the Web rather than remain on a single website). Other initiatives, like Solid – Tim Berners-Lee’s new project – are trying to find ways to give Internet users (humans or bots) more control over their browsing, as in the past.

As an individual, you can monitor your own web browsing in order to identify habits (and possibly change them). The Web Navigation Window browser extension, available online for Chrome and Firefox, can be used for this purpose. If you wish, you could also contribute to my analysis by submitting your own history (with anonymized site names) via this extension. To do so, just follow the corresponding hyperlink.

Victor Charpenay, Lecturer and researcher at the Laboratory of Informatics, Modeling and Optimization of Systems (LIMOS), Mines Saint-Étienne – Institut Mines-Télécom

This article has been republished from The Conversation under a Creative Commons license. Read the original article (in French).