Margot Dyen

Samuel Guillemot

Annick Tamaro

Attitudes towards dependence and consumption: a process rooted in past experience

Keywords: dependence, elderly people, attitudes, social learning

published or not. The documents may come

TO CITE: Margot Dyen, Samuel Guillemot & Annick Tamaro (2022) Attitudes towards dependence and consumption: a process rooted in past experience, Journal of Marketing Management, 38:9-10, 993-1013, DOI: 10.1080/0267257X.2021.2004198 "Dependence" is the fact that a person relies on medication, other individuals (professional or not), products or services to live decently. It is a multi-faceted socially constructed concept that can arise from economic, physical, legal, moral, psychological, and emotional factors, but above all, it can become a reality as individuals age and lose some of their physical and/or cognitive abilities [START_REF] Kittay | Love's Labor: Essays on Women, Equality, and Dependency[END_REF]. Facing dependence, an individual can be considered as partly vulnerable, defined according to the resources available to face a specific context or specific conditions [START_REF] Baker | Building Understanding of the Domain of Consumer Vulnerability[END_REF][START_REF] Beudaert | The vulnerability of consumers with disabilities: The benefits of taking time into account[END_REF]. In the specific case of ageing, a loss of autonomy often leads to care being provided by the individual's close circle (family, friends, neighbours, etc.). Running alongside this informal assistance are the public and private solutions for the collective care of the elderly [START_REF] Bowblis | The Impact of Minimum Quality Standard Regulations on Nursing Home Staffing, Quality and Exit Decisions[END_REF][START_REF] Guillemot | Vital service captivity: coping strategies and identity negotiation[END_REF], and the commercial solutions for service provisions (housework, meal preparation and delivery, washing and ironing, etc.) and for adapting the home with home automation (remote monitoring/remote assistance services, etc.). The overlap between consumption and dependence corresponds to current and future social and economic issues: the combination of increased life expectancy and the advancing age of the "baby boomer" generation (born in 1945-1955) will mean that an unprecedented number of elderly people will have to deal with dependence. The marketing challenges are considerable, as products and services need to be adapted to the needs and expectations of individuals to enable them to adapt to this phase of life. At the same time, individuals must be encouraged to prepare for this phase of life to alleviate the negative consequences of being vulnerable due to their dependence. However, despite the promotion of these services and adapted equipment to alleviate and/or accompany dependence, it can be challenging for people to anticipate the possible effects of ageing [START_REF] Auger | Anticipating old age? How Baby Boomers young retirees are "adapting" their housing[END_REF].

Attitude towards dependence is a relevant concept for understanding this lack of anticipation. "Attitude" refers to the relationship of individuals to an object to be evaluated and is often used in consumer behaviour studies because it has a direct effect on behaviour, as do social and personal norms [START_REF] Ajzen | Attitudes, traits, and actions: Dispositional prediction of behavior in personality and social psychology[END_REF]. How an individual imagines themselves to be dependent (cognitive dimension of the attitude), the affects that this state arouses (affective dimension of the attitude), and the planning of their intended actions (behavioural dimension of the attitude) inevitably have an influence on the preventive actions and consumption behaviours during dependence [START_REF] Hess | Attitudes toward Aging and Their Effects on Behavior[END_REF][START_REF] Coudin | Help me! I'm old!' How negative aging stereotypes create dependency among older adults[END_REF]. Therefore, the objective of this article is to gain a better understanding of the attitudes towards dependence in the elderly. To do so, we borrow the concept of Third and Fourth age [START_REF] Erickson | Dependence, independence or inter-dependence? Revisiting the concepts of 'care' and 'dependency[END_REF]. Third age is when elderly people are autonomous, and consumption decisions are not delegated to others. Fourth age is when people are dependant. It is important for consumer / marketing researchers to understand the attitude of people in their Third age toward their Fourth age. It will make it possible to formulate adapted recommendations that are aimed at reducing vulnerability towards ageing. This aims at improving consumer well-being (Mick et al., 2012;[START_REF] Ozanne | Introduction to the special issue on transformative consumer research: creating dialogical spaces for policy and action research[END_REF].

The article is structured as follows. The first part reviews the literature linking attitudes towards dependence and consumption. This allows us to identify knowledge gaps and to raise two research questions: (1) what are the different attitudes towards dependence among individuals in their Third Age? And (2) what are the psychic or social mechanisms common to all individuals that explain the construction of attitudes towards dependence? The second part of the article presents the methodology that was used to answer these questions. It presents the cultural context (France, Western European). It covers the interviewing and discusses the data collection and analysis of 30 elderly people aged 69 to 90. The third part of the article presents the findings. First it identifies and describes five attitudes that the elderly individuals have towards their dependence: "This is not my problem", "I can see myself doing that", "I am ready", "It's best to prepare for the worst", and "I don't know what to do". Second, it shows that these attitudes are mainly elaborated through a social learning mechanism. Social learning is a process of learning skills, attitudes and behaviour through observation/imitation and peer influences [START_REF] Ward | Consumer Socialization[END_REF]. It derived from the experience of people who are in the individual's close circleespecially their own parentscompared with their own resources (financial resources, material environment, social support, capacities and skills) and a subjective evaluation of loss (centrality of the tasks to be delegated in the construction of personal identity, and meanings associated with the delegation). The article concludes with a discussion of its contributions: the main theoretical contribution being that it shows attitudes are not formed in a vacuum but are rooted in the individual's past and based on a process of socialisation. In this sense, a person's experiences of their parents and their peers are fundamental. The main managerial contribution is to highlight different attitudes towards dependence, providing a basis of segmentation necessary for targeted marketing actions.

THEORETICAL BACKGROUND

The main conclusions of the consumer behaviour literature addressing dependence are presented below in three paragraphs that echo the dimensions of attitude: cognitive (e.g. stereotypes and projections), affective (e.g. emotion and affects) and behavioural.

Cognitive-based approach: dependence-related stereotypes and projections

Studies with the elderly as the target population emphasise the process of ageing as a continuum (e.g., [START_REF] Huff | The evolving family assemblage: how senior families "do" family[END_REF][START_REF] Trees | Physical and emotional nourishment: Food as the embodied component of loving care of elderly family relatives[END_REF]. As cognitive and physical abilities decline, decision-making and consumption actions are delegated to others: spouse/partner, children, other family members, or service providers and care professionals. [START_REF] Barnhart | Who are you calling old? Negotiating old age identity in the elderly consumption ensemble[END_REF] have conceptualised the "elderly consumption ensemble" (ECE) to characterise the dynamics of this particular group of health care providers. The processes of identifying as an elderly person and of becoming dependent on products, services, and others are complex. Circumstances such as critical life events (e.g., a fall, illness) often serve as a catalyst jolting them into an awareness of dependence [START_REF] Dean | From pushchairs to wheelchairs: understanding tensions in family decision making through the experiences of adult children caring for ageing parents[END_REF]. Adopting a cognitive-based approach emphasises identity negotiation in a dialogue between the social positioning (old-not old) attributed by society and by the ECE and the identity felt by the individual (not old-old) [START_REF] Barnhart | Who are you calling old? Negotiating old age identity in the elderly consumption ensemble[END_REF]. In the public realm, dependence is a negative state and has been made to appear shameful [START_REF] Erickson | Dependence, independence or inter-dependence? Revisiting the concepts of 'care' and 'dependency[END_REF]. When confronted with these negative stereotypes, individuals tend to reject them [START_REF] Hess | Attitudes toward Aging and Their Effects on Behavior[END_REF], which can explain why people generally have difficulty using, or must be persuaded to use, dependence-related products. Marketing exploits this phenomenon with the concept of cognitive agethe age with which a person identifieswhich has a much greater impact on consumption behaviour than biological age [START_REF] Szmigin | The Older Consumer as Innovator: Does Cognitive Age hold the Key?[END_REF][START_REF] Teller | Cognitive age and grocery-store patronage by elderly shoppers[END_REF].

Affective-based approach: dependence-related emotions and affects

Negative emotions associated with ageing are widespread and partially related to the desire to remain healthy, and more fundamentally related to the fear of death [START_REF] Sengès | Desired Ageing Well: Predictive validity for consumers aged 50-80[END_REF]. As such, ageing people tend to focus on positive emotionsin particular by becoming closer to their loved onesto counterbalance the negative emotions generated by the inexorable passage of time [START_REF] Carstensen | Taking time seriously: A theory of socioemotional selectivity[END_REF]. Family studies have focused on the social dynamics within ECE; findings highlight the importance of family routines, rituals and habits [START_REF] Trees | Physical and emotional nourishment: Food as the embodied component of loving care of elderly family relatives[END_REF][START_REF] Godefroit-Winkel | The interplay of emotions and consumption in the relational identity trajectories of grandmothers with their grandchildren[END_REF], and of the anchoring role of possessions [START_REF] Huff | The evolving family assemblage: how senior families "do" family[END_REF] as the elderly person gradually loses their faculties and descends into dependence. As a result, personal activities/identities tend to be set aside in favour of family and collective identities [START_REF] Karanika | Consumption through the Ambivalent Prism of Intergenerational Support[END_REF]. These relational configurations create stress and ambivalent emotions, fluctuating between love and guilt, selfishness and compromise [START_REF] Dean | From pushchairs to wheelchairs: understanding tensions in family decision making through the experiences of adult children caring for ageing parents[END_REF]. To cope, the protagonists will implement diverse and varied strategies, and sometimes even "power struggles" are played out so that everyone finds their place [START_REF] Trees | Physical and emotional nourishment: Food as the embodied component of loving care of elderly family relatives[END_REF]. For example, the children who are also caregivers use strategies to take control over decisions (e.g. not informing their parents), while the parents develop strategies to maintain control (e.g. procrastination, vetoing, making alliances with siblings or health professionals, etc.) [START_REF] Barnhart | Who are you calling old? Negotiating old age identity in the elderly consumption ensemble[END_REF][START_REF] Barnhart | Like a member of the family: including and excluding paid caregivers in performances of family[END_REF].

Behavioural-based approach: Intentions to use dependence-related products or services

Here, the subjective experience of the ageing process must always be the predominant concern, in particular, the acknowledgement that the process is not homogeneous and can vary on several dimensions: as synthesised by [START_REF] Moschis | Consumer Behavior in Later Life: Current Knowledge, Issues, and New Directions for Research[END_REF], it includes at least a biological dimension (e.g. decline of biological, physical and cognitive functions), a social dimension (e.g. modification of social roles, isolation) and a psychological dimension (e.g. relationship to time). The interactions between these dimensions of ageing lead to different configurations that affect consumption behaviour intentions. For example, people without significant health problems who view free time in retirement as an opportunity, tend to remain agentive and proactive and continue to develop life projects [START_REF] Schau | Consumer identity renaissance: the resurgence of identity-inspired consumption in retirement[END_REF]. Moshis (1993) shows that people who are in good health but socially isolated tend to consume less and to be less receptive to age-based marketing strategies ("healthy hermits"), whereas people who are in poor health but socially connected are the most likely to use dependence-related products ("ailing outgoers").

Research questions

The current state of knowledge in this field has been developed from studies with interviews and observations of individuals in their Fourth Age, i.e. people with physical and/or cognitive dependence due to old age [START_REF] Erickson | Dependence, independence or inter-dependence? Revisiting the concepts of 'care' and 'dependency[END_REF], or of people who make up the ECE (family, health professionals, etc.). With the objective of promoting dependence anticipation and prevention, the population under study here will be people in their Third Age, i.e. elderly people in relatively good health and without serious dependence problems (i.e. not involved in a ECE).

Moreover, current research tends to focus mainly on one dimension of attitude; the literature review shows that the dependence-consumption relationship tends to be explored under its cognitive (e.g. [START_REF] Barnhart | Who are you calling old? Negotiating old age identity in the elderly consumption ensemble[END_REF], affective [START_REF] Trees | Physical and emotional nourishment: Food as the embodied component of loving care of elderly family relatives[END_REF] or behavioural (e.g. [START_REF] Moschis | Gerontographics: A Scientific Approach to Analyzing and Targeting the Mature Market[END_REF] aspect. The present study seeks to complement this knowledge by studying how the different components of attitude interact with one another. This is important because the same behaviour can be coupled with distinct affects and projections. Considering all three dimensions simultaneously will enable consumer profiles to be differentiated, thereby making it possible to identify people who do not need help and those who are looking for solutions. It will also provide an opportunity to identify the type of help sought. Therefore, the first research question (RQ) can be formulated as follows:

RQ1: What are the different attitudes towards dependence among individuals in their Third Age?

Past research has focused on the strategies that older people deploy to cope with dependence, but little is known about the construction of these attitudes. Studying the grounds on which individuals construct their attitudes towards dependence will improve understanding of how individuals in their Third Age apprehend this phase of life and how they prepare themselves for their Fourth Agethat of dependence. Thus, the second research question can be formulated as follows: RQ2: Beyond person-specific physical and cognitive health, what are the psychic or social mechanisms common to all individuals that explain how attitudes towards dependence are constructed?

METHODOLOGY

Using Grounded Theory [START_REF] Glaser | Discovery of grounded theory: Strategies for qualitative research[END_REF], this present study adopts a phenomenological approach towards dependence and examines how lived experience leads to a specific attitude towards dependence in the elderly. Phenomenology can be defined as the study of things (phenomena and events) as seen and experienced from a personal perspective [START_REF] Van Manen | Phenomenology in its original sense[END_REF]. Thus, the data collection aims in a first instance to capture experience in its primordial origin or essence, without interpreting, explaining, or theorizing it [START_REF] Husserl | Ideas for a pure phenomenology and phenomenological philosophy. First book: General introduction to pure phenomenology[END_REF].

Cultural context

The study is conducted in France -Western Europe. France has seen a rise in the percentage of over 65-year-olds and dependant individuals in its population (French Statistics Bureau, 2020). In 2040, more than 25% of the population will be over 65 compared to 20% in 2019. In the same period, the percentage of over 75-year-olds should increase even more, rising from 9.4% to 14.5%. To support its ageing population, the French government has based its policies on a report by a panel of experts, published in 2019. The Rapport Libault (Libault report, 2019) stresses the importance of anticipating and taking preventative action, notably by supporting people in anticipating and managing their dependence. Thus, such as France public policies tend to advocate autonomy and resilience, particularly through the medication of individuals, rather than their (inter)dependence. Despite these efforts, ageing is often the subject of denial in Western European societies. There is also a certain form of exclusion. The care of the frail elderly is carried out in nursing homes dedicated to dependency. These institutions are characterised by a chronic lack of human and financial resources [START_REF] Sebastiano | The Effect of Capacity Management Strategies on Employees' Well-Being: A Quantitative Investigation into The Long-Term Healthcare Industry[END_REF]. Opinion surveys indicate that older people would prefer not to have to use such services [START_REF] Leblanc-Briot | Fin de vie des personnes âgées[END_REF]. Philosophers explain this marginalization by the stereotypes attached to ageing which reflect the fragility of existence and our own finitude [START_REF] Aubry | Quelle place pour la vieillesse dans notre société ?[END_REF].

Data collection

In a naturalistic [START_REF] Lincoln | Intergenerational influence: Roles of conformity to peers and communication effectiveness[END_REF] and interpretive approach, the present research is based on a qualitative methodology. Respondents were recruited by word of mouth and snowball sampling through retiree associations on the one hand, and researchers' interpersonal connections on the other (e.g. relatives' neighbours, friends' relatives, etc.). In order to identify the greatest possible diversity, the "illustrative sampling" method [START_REF] Turrentine | Car buyers and fuel economy?[END_REF] was used. The homogeneous criterion for the study sample was elderly individuals (70 years of age and over, with one respondent a few months away from her 70th birthday) who made independent consumption decisions that were not delegated to a "elderly consumption ensemble" (ECE). This did not exclude the use of services (e.g. meal preparation or delivery) or the purchase of dependence-related products (e.g. home automation). The sample was designed to vary socio-demographic characteristics such as age, marital status and area of residence (urban, suburban, rural). The sample size was determined according to the principle of theoretical saturation [START_REF] Charmaz | Constructing grounded theory: A practical guide through qualitative analysis[END_REF]. Finally, 30 French people aged 70-90 were interviewed (Appendix 1). The interview guide was organised around life trajectories and domestic consumption behaviours (cooking, shopping, housework, DIY, gardening, etc.). It was purposely broad enough to holistically understand the respondents' ways of living and their feelings, emotions and expectations through their life journey. As our research problem was about understanding the complexity of dependence and how it is formed, the main objective of the data collection was to gain the respondents' trust and to accompany them in their self-reflexive and recollection work. As regards the interviews, emerging ideas and questions enabled the interviews to be conducted with more accuracy each time, through an iterative process [START_REF] Charmaz | Constructing grounded theory: A practical guide through qualitative analysis[END_REF]. In line with a phenomenological approach, the interviews took the form of a discussion in which individuals were free to digress [START_REF] Brinkmann | Doing interviews[END_REF]. The interview guide was mainly used to ensure that the predefined themes were covered, and that opportunities for follow-up were provided. Interviews lasted on average 1 hour and 10 minutes, ranging from 20 minutes to 2 hours and 30 minutes. They took place in interviewees' homes, a relevant context to accompany respondents in their recollection work. Additionally, photos, objects or house layout were sometimes useful pieces for follow-up questions (from the interviewer) or answers (from the respondent). Interviews were recorded with the explicit agreement of the participants: they signed a consent form in line with the ethical assessment validated by the University to which the authors are affiliated. The consent form was read out loud by the interviewer to ensure that this potentially vulnerable population fully understood the situation, and they were also informed that they could stop the interview whenever they wished. Interviews were fully transcribed.

Data analysis

The analysis followed the Grounded Theory process [START_REF] Glaser | Discovery of grounded theory: Strategies for qualitative research[END_REF] involving an iterative process between the results emerging from the collected data and the literature published at the time of analysis. "Grounded theory methods […] are a logically consistent set of data collection and analytic procedures aimed to develop theory" (Charmaz, 1996 p. 27). In our case, this theory development method has been applied to theorising the construction process of attitudes towards dependence in elderly people. Three coding phases followed: first, open coding to identify and categorise the elements relating to attitudes towards dependence. Each of the three dimensions of attitude were considered (cognitive, emotional, and behavioural). The data were initially coded by the first author; the other authors participated in the analysis to abstract the results through ascendant thematisation. Second, axial coding was used to link together the elements, whether they be context, facilitating conditions (e.g. peer experience), actions or strategies and consequences of the phenomenon [START_REF] Strauss | Qualitative Research, Techniques and Procedures for Developing Grounded Theory[END_REF]. Nine categories emerged from this coding that were all linked to the origin of the attitude towards dependence (e.g. from observing their parent(s)' experience, through their own role of caregiver, centrality of the task to be delegated, etc.). Third, a selective coding allowed the classification of the nine pilot categories, namely the emerging triptych: (i) social learning compared with (ii) an assessment of one's own resources and (iii) a subjective evaluation of loss.

RESULTS

The results are summarised in Figure 1. In the middle of the figure, it can be seen that there are five attitudes towards dependence that emerged from our study field (RQ1): "This is not my problem", "I can see myself doing that", "I am ready", "It's best to prepare for the worst", and "I don't know what to do". At the periphery of the figure are the elements that guide individuals towards one or another of these attitudes (RQ2). The results reveal that the construction of attitudes is based on a triptych composed of a social learning process, notably shaped by an individual's (i) observations of their parent(s)' and peers' experiences, which takes into account (ii) their own resources and (iii) their subjective evaluation of dependence-related loss. The following sections clarify and illustrate each of these points.

Attitudes towards dependence

RQ1 was formulated to determine the respondents' attitudes towards dependence. To do this, the position of individuals on each attitude dimension was considered. The first is the cognitive dimension; some individuals do not project very much into dependence (e.g. "We don't think about it, because as long as we're in good shape, we don't think about it. That's how I see it anyway." -Arlette, F, 75), whereas others do. These projections and stereotypes are diverse and varied and cover several types of dependence: home support with very little help, home support with assistance for some/many tasks, and retirement homes/nursing homes. The second is the affective dimension. Once again, there is a continuum between individuals who apprehend (e.g. "as long as my health doesn't deteriorate! That's what scares me", Geneviève, F, 81), and those who see this looming milestone serenely (e.g. "it's going to happen naturally" -Norbert, M, 70). The third is the behavioural dimension, with some respondents implementing actions to prevent dependence ("I've already called all the companies to adapt the house" -André, M, 71) while others do nothing. In the end, the combination of individuals' "positions" on these three continuums made it possible to identify five attitudes that we have named using the verbatim of the individuals who adopt them: "This is not my problem", "I can see myself doing that", "I am ready", "It's best to prepare for the worst", and "I don't know what to do". Each individual can be classified in one of these attitudes. This is not my problem. This attitude is shared by individuals who do not project themselves into dependence and therefore do not make any particular provision for their future, claiming not to feel any affects or emotions in this respect. It is mostly derived from the cognitive dimension of attitude. Some individuals want no more to do with the subject: "Well, I don't know, the question doesn't come up. At my age I can carry on with my activities. No, it'll happen gradually. We don't think about it, thank goodness!" (Henri, M, 77). Other individuals wish to live from day to day, so their attitude towards dependence is related to their attitude towards life: "Personally, I don't think about my future. I don't want to know! At our age, what matters is today, the present moment. Where will we be in 10 years? And will we still be here?" (Michelle, F, 75). Others do not feel concerned about dependence because they still consider themselves to be too young or healthythe attitude towards dependence thus echoes self-representation: "I don't think about it, no, I've got too much energy" (Marie, F, 83). This self-representation is independent of objective facts, since even if some daily activities are starting to be difficult, they feel they can carry on as before: "Doing the housework is hard. Because I'm hurting all over now. It's a worry. Even shopping has become a bit of a nightmare!" [Can you see yourself delegating these tasks?] "Oh no, I'm still in good shape, in several years' time maybe? I can't say more than that really, but as long as I can, I'll do it" (Marianne, F, 72). This cognitive dimension of attitude can go as far as denialor resistanceas in the case of Yvette (F, 90) who makes it a point of honour to go upstairs ("it's my own personal Mount Everest!") and who does not sleep in the room that her children have arranged on the ground floor of her home.

I can see myself doing that.

This attitude towards dependence arises when people construct scenarios relating to their future state (cognitive dimension) and who envisage possible actions to be implemented (behavioural dimension). However, imagined actions are not the same as implemented actions: people know what they will do when the time comes and generally envisage the future serenely (affective dimension): "Well in ten years' time, I won't be here any more! For me, it's just a few years, that's all. [...] what's certain is that I don't see myself going into a retirement home [...] when the time comes it'll be home help for me" (Berthe, F, 90). A few people, however, are well aware that this will probably not happen exactly as planned and some have come up with a "plan B" (cognitive dimension): "You have to climb up a dozen stairs to go upstairs. I won't be able to live on the first floor. Seriously, no, I'm not at that point yet, but the older you get, the more you have to think about it [...] Afterwards, if it doesn't go as planned, I'll have to go into a retirement home. That doesn't really appeal to me much. But if it's a constraint, I'll make do. [...] You've got to be realistic. It doesn't scare me, it's just reality" (Alfred, M, 79).

I am ready.

As with the "I can see myself doing it this way" attitude, the people here have implemented their action plan to deal with potential dependence. They have taken steps and say they feel calm about the future because they feel ready: "I bought an apartment, it really is well designed for elderly people: there's a lift, everything is electric, the shutters, everything. It's fantastic [...]. So there you go, I'm ready. I'm ready if I have to die too" (Marguerite, F, 76). Actions can also take the form of the consumption of services such as taking out a dependence insurance policy to assert one's wishes: "If I become dependent I don't want to go just anywhere! There are nursing homes that are very good. I talked about it with my husband and I took out insurance for long-term care so that I can be sure I'll get to go wherever I want" (Paule, F, 70).

It's best to prepare for the worst. Individuals who adopt this attitude are constructing scenarios of a rather pessimistic future health status (cognitive dimension). This makes them very anxious (affective dimension). They tend to put actions in place to deal with and prepare for it (behavioural dimension): "I decided to get a cleaning lady because it's complicated for someone to change the pace of their life when they're old. So, I told myself that I had to get used to it now." (Pierrette, F, 81).

I don't know what to do.

This attitude is similar to the "best prepare for the worst" attitude in the sense that people are envisaging pessimistic scenarios. The core of this attitude is thus the cognitive dimension, and it provokes negative affects (emotional dimension) which, instead of inciting people to act, paralyzes them: "I don't know how it will happen, I never stop worrying about it [...] The day I won't be able to do my shopping anymore, to make food anymore .... I don't know, I don't know what I'll do, I've got no idea." (Anita, F, 77). This "paralysis" is so strong that some people consider letting others decide for them, totally withdrawing from the cognitive dimension of attitude: "Because that [being dependent] is one of the worst scenarios I can imagine. So I don't really care what they do with me, I don't care. The main thing is not to get on other people's nerves. That's it." (Suzanne, F, 87).

A social learning process

RQ2 aims to identify the psychological and social mechanisms on which attitudes are grounded. The results highlight a social learning process. When respondents project themselves into dependence, they mobilise what they have experienced directly through the observation of their parent(s)' situation and their own role as caregiver. This "primary" experience is updated and supplemented by what they observe from the experiences of their peers.

Parents and the role of caregiver. Most respondents spontaneously refer to their observations and experiences of their parents' situation (in the broad sense: parents, grandparents and sometimes siblings) and ultimately to their own role as caregiver. Although the phase of parental dependence generally went well, respondents do not ask themselves too many questions (e.g. "I will do the same as my mother", Maryse, F, 73). The parent(s)'s experience also makes it possible to anticipate certain things; for example, André (M, 71) has already adapted his house: "I saw how it went with my mother, so when we bought our house, there was the possibility of a ground floor with a bathroom, which we refurbished to make it more practical. [...] Yes, I've already called the companies to adapt the house". Pierrette (F, 81), for her part, decided to take on a cleaning lady "to get used to it" because she had seen from experience that her mother had a lot of trouble changing her lifestyle. Parents' experience also allows individuals to say what they do not want for themselves. For example, Suzanne (F, 87), who took her dependent father into her home, found it very tiring and time consuming, so she does not want to impose it on her own children by moving in with them.

Peers. An individual's judgment based on their parent(s)' experience is enriched and balanced by the experience of their peers, friends and neighbours included. Comparison offers different points of view and enriches the reflection and construction of projections about dependence. For example, Paule (F, 70), whose mother still lives in her own home, does not wish to reproduce the same pattern, which she feels is "stubbornly staying at home". Her projection into dependence is instead based on her former neighbour: "She's moved into sheltered housing; she likes it a lot". Similarly, the verbatim of Norbert (M, 70) perfectly illustrates how the experience of close friends and relatives can change one's judgment: "I have a couple of friends who sold their house for health reasons [...] they bought a small apartment in a seniors' residence. Yes, they bought this apartment, and I went to see them several times. And it's true that they are happy in their residence for seniors. I wouldn't go as far as to say that they feel young again, but almost! So yes, it does make you think, some people refuse to consider it, but I wouldn't mind moving into this type of residence. It's actually very good: there's lots of people around like you and you get to know each other".

An assessment of one's own resources

The previous section indicates that the individuals interviewed base their attitudes on a social learning process. In addition, individuals will judge their parent(s)' and peers' experience in light of their own resources. The resources discussed in the interviews are financial resources, the material environment, social supportespecially that of one's childrenand abilities and skills.

Financial resources. This is a key element in the understanding of the respondent's relationship to dependence. It is easier to experience negative affects when these resources are lacking. For example, Anita's (F, 77) anxiety about dependence issues stems largely from her low income: "When you get someone to help you, it comes at a cost. And for me, financially speaking, it's very hard. I have almost no income because I stopped working the day I got married and now I'm all alone [widowed]." Physical environment. Beyond financial resources, individuals will build their future projections based on the material means in their environment. This may include material possessions such as an adapted apartment: "There's a lot of talk about staying at home these days. But for me, for example, that wouldn't be easy, because of the stairs. If you want to stay at home then you need a room on the ground floor" (Marie-Pierre, F, 77), or more broadly, to find in the environment conditions that are adapted to the dependence in terms of urban planning or accessibility to shops, etc. (Marie-Pierre, F, 77). Here, we can compare the case of Germaine (F, 72), who finds the means to reassure herself in her environment: "Even though the day will come when I won't be able to drive any more, in the village there's the butchers', the doctors', the dentist, bakers', there's everything here", to that of Guy (M, 72), who is more isolated and has fewer means to provide for his needs alone: "the councils couldn't care less, there's no public transport for people like us who can't get around".

Social support.

Respondents also construct their attitudes about their dependence on social supports that they can rely on when the time comes. Several respondents expressed that they do not feel that they can rely on their children to help them, either because of conflictual relationships, geographic reasons, or because they already have a full life: "My daughter, with her job and her three children, I don't know how she would be able to take care of me [...] she'll put me in a retirement home, end of story." (Marguerite,F,76). Similarly, Marie (F, 83), who took care of her mother, does not envisage her children doing the same because she is not on good terms with them, which is why she took the initiative to take out dependence insurance to finance home help. On the contrary, other respondents are confident that their children will be able to help them. This assistance has sometimes already begun: Suzanne (F, 87) and her son share the shopping task between them (Suzanne writes the list and her son does the shopping). In addition, beyond the family, close solidarity with friends and neighbours can also be established. Annie (F, 85) is an example of this: since she does not have a driving license and therefore cannot "do a big shop", when her neighbour goes shopping he takes her along too.

Abilities and skills. The issue of skills (know-how and capacities) is crucial in how individuals perceive and anticipate their dependence. Many respondents become aware of their potential dependence as they perceive a gradual decline in their abilities. This is particularly the case when a form of "intra-family" dependence emerges. Very often, the sharing of tasks within a couple sometimes becomes problematic when one half of the couple is no longer able to carry out their share. Thus Françoise (F, 69) has started to worry because she knows that she will not be able to count on her husband to do the shopping or cooking: "My husband has never cooked food in his life and is incapable of doing so. I'm exaggerating when I say that, but that's more or less the truth. I'm sure that if something happens to me, even with my back against the wall he wouldn't cook for me." In addition to household tasks, mobility is also an issue. For example, Mireille's (F, 85) husband "drives her around" and she knows that in a while neither of them will be able to drive anymore. Widowhood is a major event in the overall approach to dependence and end of life, as in addition to the trauma linked to the loss of a loved one, this stage of life changes what is possible to do and gives rise to new needs that need to be met such as mobility ("When my husband was alive, it was him who'd do all the driving" -Annie, F, 85), cooking ("My wife was the one who cooked, I don't know how to. As long as I can do the shopping, it's okay, I'll buy ready-made meals. When I can't do that anymore, we'll have to see ..." -Guy, M, 72), or more generally to help with tasks previously carried out by the person who is no longer there.

A subjective evaluation of loss

In addition to the social learning process and the respondent's assessment of their own resources, the results highlight a process of subjective evaluation of "loss" in the construction of attitudes towards dependence. In particular, it seems that the construction of attitudes is a differential dynamic depending on the nature of tasks to be delegated, and the meaning given to this delegation. Ultimately, respondents are more inclined to delegate certain tasks than others.

Centrality of the task to be delegated in the construction of personal identity. Some respondents express a particular attachment to certain tasks, which justifies their unwillingness to delegate them: they may be reluctant to delegate because they enjoy it, or because they feel they have developed some level of expertise in it and are afraid that the other person will not do it as they like. For example, Rose (F, 90) uses a cleaning lady to clean her house, and her family to do the shopping, but she would find it difficult to delegate food preparation for fear that her demands and way of doing things would no longer be respected: "If I can't cook any more. Then yes, I would be very annoyed. I'm very concerned that I'll be given ready meals, meals that aren't like my cooking. Frozen meals, that kind of thing, God no, I wouldn't like that." This centrality of cooking is found in many women of this generation, for whom "being a good cook" has been an important part of the recognition of their identity as wife and/or mother (e.g. Suzanne, F, 87; Colette, F, 69). In addition to culinary skills, other activities represent this centrality of selfidentity. This is the case with grocery shopping ("I wouldn't like to delegate the shopping because I like to do it [laughs] [...] because it's one of my pleasures" Sandrine, F, 73) or housework ("I'll never get a cleaning lady because it [the cleaning] wouldn't be done well enough", Anita, W, 77).

Meanings associated with the delegation of tasks.

The delegation of a task appears more or less conceivable depending on the meanings associated with its delegation. Thus, if the person experiences physical tiredness and/or lassitude, delegation may appear to be an attractive alternative allowing them to focus on more pleasant activities. Martine (F, 71), for example, finds it increasingly difficult to do her housework on her own, and asking for help does not seem out of the question to her: "I'm well aware that the house is too big, there's too much housework to do, it's tiring... It's not going to be possible for much longer [...] Yes, it's true that getting somebody in to help could be a relief." Beyond the question of the task, there is the question of who to delegate to. Staying within the family circle seems like an option for some respondents: "It is not the same, if it's one of my daughters doing my shopping it's not outside the family, it's normal. If it's someone else who does my shopping, it's not the same thing ... this person doesn't know us, we'd have to give them the list" (Michelle, F, 75). We understand in this testimonial that the fact of soliciting the family is not perceived as recourse to outside help, and that recourse to a person outside the family or close circle is a more complicated process involving more of a commitment. Experience and familiarity with the delegation are therefore important. The tasks that the majority of respondents plan to delegate are housework and gardening. In fact, these have sometimes already been delegated in previous life stages (totally, partially or temporarily). Having already used service companies therefore makes it easier to project oneself into dependence and the delegation of other tasks: "Yes, we had a cleaning lady before, but it's trained staff, well, anyway. [...] After that, if we had someone who could cook for us, for example, the way I see it is that paying for that would be exactly the same as paying for the cleaning lady." (Guy, M, 72).

DISCUSSION

The identification of five attitudes towards dependence provides a balanced view of vulnerability in the elderly. While the results confirm many of the mechanisms highlighted in the literature (e.g. integration of a socially constructed image, comparison with individual resources [START_REF] Barnhart | Who are you calling old? Negotiating old age identity in the elderly consumption ensemble[END_REF]), they also shed light on new mechanisms such as the phenomenon of social learning to dependence and the differential vision of dependence. This discussion sets out the main contributions of the study and proposes managerial recommendations.

Highlighting the nuances in attitudes towards dependence in the elderly

Findings reveal five attitudes towards dependence in elderly individuals. In order to highlight the contribution of this typology, we compare it to other segmentations of older people, in particular that of [START_REF] Moschis | Gerontographics: A Scientific Approach to Analyzing and Targeting the Mature Market[END_REF] who identified four types of elders. In this respect, the attitude "This is not my problem" is consistent with Moschis' (1993) profile of "healthy indulgers", people in relatively good health who live well as they age and who, if they have problems, believe they can manage them. The attitudes "I am ready" and "I can see myself doing that" correspond more to Moschis' (1993) "ailing outgoers" profile, which describes people who, although vulnerable because of their health, actively seek solutions. In both cases, the portrait painted of the elderly is that of people who are proactive in their choices and decisions (e.g. [START_REF] Schau | Consumer identity renaissance: the resurgence of identity-inspired consumption in retirement[END_REF]. The two other attitudes identified are the attitudes of people who feel more vulnerable to their ageing condition, and in this sense are similar to Moschis' (1993) "healthy hermits" and "frail recluses". This attitude-based approach enabled us to identify two opposing positions created by age-related negative affects: fear of "poor" ageing prompting people to be reactive ("It's best to prepare for the worst") and the feeling of being "stuck" ("I don't know what to do").

From a managerial perspective, we can draw on these elements to propose action aimed at well-being. Indeed, the distinction is clear between those people who need substantive support ("I don't know what to do" attitude), those who just need information ("It's best to prepare for the worst", "I can see myself doing that" attitudes), and those who will be unreceptive to marketing actionseither because they already have a solution ("I am ready" attitude) or because they do not feel concerned ("This is not my problem" attitude).

The process of socialisation involved in the attitude towards dependence

The second objective of this research was to understand how this attitude is constructed. Findings highlight a process of social learning shaped by the lived experiences of the parents and peers. Past research has already highlighted the importance of family background in the situation of dependence. In particular, the material (e.g. family possessions) and the immaterial (e.g. family aspects such as inter-personal relationships, shared memories, etc.) are anchors on which elderly people and their caregivers can rely [START_REF] Huff | The evolving family assemblage: how senior families "do" family[END_REF]. Thus, in a family with an elderly dependent person, personal activities/identities tend to be set aside in favour of familial and collective identities [START_REF] Karanika | Consumption through the Ambivalent Prism of Intergenerational Support[END_REF]. Similarly, family routines, rituals and habits (e.g., holiday meals, birthdays) take precedence over personal habits [START_REF] Trees | Physical and emotional nourishment: Food as the embodied component of loving care of elderly family relatives[END_REF][START_REF] Godefroit-Winkel | The interplay of emotions and consumption in the relational identity trajectories of grandmothers with their grandchildren[END_REF]. Our results highlight a complementary intergenerational phenomenon: by explicitly referring to their parent(s)' experience in the construction of their own attitude towards dependence, our respondents highlighted the phenomenon of "socialisation" in dependence attitudes. Consumer research describing this phenomenon often involves children (e.g. [START_REF] Roedder-John | Consumer Socialization of Children: A retrospective Look of Twenty-Five years of Research[END_REF], adolescents and sometimes young adults (e.g. [START_REF] Beatty | Adolescent Influence in Family Decision Making: A replication with Extension[END_REF]. Indeed, norms, attitudes, values and consumption practices are formed primarily within the household through a phenomenon of observation/imitation (primary socialisation) [START_REF] Moore | Passing the Torch: Intergenerational Influences as a Source of Brand Equity[END_REF][START_REF] Ward | Consumer Socialization[END_REF]. Younger generations will then select, confront and update these elements with their peers outside the household (secondary socialisation) [START_REF] Lincoln | Intergenerational influence: Roles of conformity to peers and communication effectiveness[END_REF][START_REF] Moschis | Consumer Socialization: A Theoretical and Empirical Analysis[END_REF]. The socialisation of adults is rarely studied, except for "reverse socialisation" when a parent changes their norms, attitudes, values and practices, usually in relation to technology and clothing, by observing and imitating their children [START_REF] Shah | Toward a Theory of Intergenerational Influence in Consumer Behavior: An Exploratory Essay[END_REF]. Life events are moments that make it possible to reactivate family models. Thus [START_REF] Ladwein | Le capital transgénérationnel : la transmission des pratiques de consommation de la mère vers sa fille[END_REF] show how young women who become mothers tend to adopt their mothers' practices, as this is the reference model for them. The dependence process described in our findings is very similar to the socialisation process: the anchor point is the parents' experience, which is a reference (primary socialisation) and the experience of peers then enriches, updates or offers a counterpoint to this primary experience (secondary socialisation). The present research shows that this process is indeed present throughout life and that it also concerns the last part of life which tends to be forgotten by life span models and theories. This intergenerational perspective thus makes it possible to link the developmental concerns of individuals of different generations; people who are now elderly seek to maintain their integrity by referring to the situation experienced by their parents, and by positioning themselves in relation to their children [START_REF] Guillemot | Intergenerational transmission in consumer behaviour: An integrative conceptual framework and future research directions[END_REF].

However, dependence management is evolving and subject to change, developing at different rates in different countries and different environments. As such, the observation/identification process is complicated and there is not a one-size-fits-all approach. Community-based care can be difficult to envisage when the reference is care by family members, and vice versa. It is therefore important to offer "secondary socialisation spaces", to promote meeting places and times, in order to encourage the sharing of experiences. For example, informal "Third places" such as "senior meetups" can be ideal for holding decentralised debates and meetings on ageing issues, and such fruitful exchanges may generate some new, hereto unthought of adaptation solutions.

Highlighting a differential vision of dependence

The third contribution of the research is to show that the path to dependence is a personal one based on reference models, available resources and subjective experience of loss. These results partially overlap with important concepts previously highlighted in the literature such as the subjective position of elderly people (e.g. [START_REF] Barnhart | Who are you calling old? Negotiating old age identity in the elderly consumption ensemble[END_REF] and resource integration amongst vulnerable consumers (e.g. [START_REF] Piacentini | Consumer resource integration amongst vulnerable consumers: Care leavers in transition to independent living[END_REF]. Our research specifies that this negotiation can be contextual and depends on the centrality of the task to be delegated. Indeed, as the older person loses independence, they will seek to preserve and maintain the things that characterise their personal identity. For example, not being able to cook is difficult for a person who has always been valued as a "good cook" (here, the centrality of identity). This underlines the importance of approaching well-being through its eudemonic component. Eudaimonic well-being considers well-being as the person's feelings of fulfilment [START_REF] Sharma | Hedonic And Eudaimonic Well-Being Outcomes From Co-Creation Roles: A Study Of Vulnerable Customers[END_REF] and is very important for elderly people [START_REF] Plaud | Service Interactions and Subjective Well-Being in Later Life[END_REF]. Models of successful ageing emphasise the identity work that the older person must do to compensate for the loss of an important role (e.g. [START_REF] Schulz | A life span model of successful aging[END_REF]Heckhausen, 1996, Rowe and[START_REF] Rowe | Human aging: Usual and successful[END_REF]. Our results offer communication levers to reduce the negative perception associated with task delegation, and to help the individual accept and implement delegation. It is recommended that task delegation be presented as an opportunity and a lever for "wellbeing", a choice that is in one's best interests (relief) and under one's control (e.g. one individual chooses to delegate so that they will be free to do other things, to accompany and transmit my experience, etc.). It should never come from a negative register corresponding to a situation to be endured or a constraint to which one must resign oneself. Given the importance of identity processes, it is preferable that messages are in line with a well-being and "living in the present moment" logic rather than a prevention one in which the person concerned is kept from seeing themselves as "dependent". It would thus be interesting to present the delegation of tasks from a practical point of view, while the argument for (re)designing housing will be developed from a perspective of greater comfort in the present moment. Therefore, in line with the attitudes "I don't know what to do" and "This is not my problem", the "simpler now" lines of communication would make it possible for individuals to choose to adopt products and services before they become a necessity or even indispensable at a "later" date.

More generally, these recommendations need to be turned into actions in collaboration with the elderly people, to ensure the accuracy of the actions designed. Further studies could borrow from the principles of Participatory Action Research (PAR) (Ozanne and Saatcioglu, 2018) who, just as this research, aim at understanding and improving society at the same time. Reason and Bradbury (2001, 1) define PAR as "a participatory, democratic process concerned with developing practical knowing in the pursuit of worthwhile human purposes". One of the specificities of this approach is that, through a process of co-creation, it initiates a change within the population studied just through the research process. Such an approach echoes the result of our study according to which exchanges around the issue of dependence, via a process of social learning, can constitute a source of attitudes in favour of dependency management (e.g. "it's better to prepare to the worst"), and could help empower elderly people towards ageing. Through this process, the aim would be to alleviate vulnerability towards ageing, and thus foster wellbeing. In the French context, such an approach would allow for more bottom-up interventions, which would nuance the very uniform and negative view that the population has of the Fourth age. More globally, it would be relevant to mobilize the results of this study in other countries, knowing that attitudes towards the Fourth age are very culturally situated. The PAR approach would allow for a deeply comprehensive and recommendation-oriented approach to this issue.

CONCLUSION

The objective of the article was to gain a better understanding of attitudes towards dependence in the elderly in order to support this population in the preparation of the last phase of their lives. This research focused on individuals in their Third Ageautonomous people whose consumption decisions are not part of an elderly consumption ensemble (ECE). Findings highlight five attitudes towards dependence that are distinguished by their cognitive, affective or behavioural dimension ("This is not my problem", "I can see myself doing that", "I am ready", "It's best to prepare for the worst", and "I don't know what to do"). Findings also highlight that these attitudes are not rooted in a vacuum, but are anchored in the individual's past and acquired through a socialisation process that takes into account the meaning of the activity to be delegated. These elements of knowledge offer professionals in the field of elderly dependence a basis for segmentation, as well as lines and moments of communication.

This research does have limitations, but nonetheless, they are possible avenues for future investigation.

First, the "This is not my problem" attitude should be clarified. It includes individuals who say they do not make projections about potential dependence, or do not have any particular feelings about this subject. In fact, they do not think about setting up preventive actions and say that they do not feel any particular emotion. This profile is intriguing and could actually be the result of several internal mechanisms. Why do they not make a projection? Is it because of avoidance, the ostrich syndrome of not facing reality? Or Optimisation? Or because of denial? In any case, it would be advisable to extend the results with a complementary study to answer these questions and possibly distinguish more detailed attitudes.

On the other hand, the results suggest that attitude building is an iterative process. Since resources and subjective experiences of loss evolve in response to life events and biological, social and psychological ageing processes, it is understandable that attitudes may change as the individual gets older. In order to understand this iterative process better, a longitudinal study is recommended in which the same individuals are interviewed on a regular basis over time to follow the evolution of attitudes and the adjustments made as the projections are confirmed or not.

Finally, this study is not able to determine the importance and diffusion of different attitudes among the population. A next step would be to construct a scale to measure attitudes toward dependence. One way of doing this would be to generate reflexive items for the three dimensions of the attitude (cognitive, affective and behavioural) and to proceed through all the steps formalised by [START_REF] Churchill | A paradigm for Developing Better Measures of Marketing Constructs[END_REF] paradigm updated by [START_REF] Rossiter | The C-OAR-SE procedure for scale development in marketing[END_REF] in order to arrive at a reliable and valid scale. A second step would be to distribute this scale to a representative sample of the population. Factor and typological analyses would make it possible to highlight the different profiles of the attitudes and, more importantly, to measure the importance and distribution of each of the five attitudes. Comparisons could then be made by age, sex, location, and even cultural and international comparisons. In addition, this would make it possible to segment the population and carry out more targeted action campaigns.

Figure 1 .

 1 Figure 1. Attitudes towards dependence and the psychosocial mechanisms that drive them

Funding

This study is funded by Région BRETAGNE as part of the NUTRICHIC research programme.


Yulliwas Ameur
email: yulliwas.ameur@lecnam.net

Samia Bouzefrane

Vinh Le

Thinh

Handling security issues by using homomorphic encryption in multi-cloud environment

Keywords: homomorphic encryption, multi cloud computing, security, privacy, OpenEHR, electronic medical records

Taking advantage of the high performance and powerful data processing capabilities of cloud computing technology, externalizing data to the cloud platform is considered as an inevitable trend in the digital field today. However, ensuring the security and privacy of data remains a major challenge. To overcome this drawback, a multi-cloud platform is proposed to improve privacy and high availability of data. A multi-cloud platform that integrates public, private, and managed clouds with a single user interface. Cloudhosted data is distributed among different data centers in a multi-cloud environment based on cloud reliability and data sensitivity. In terms of security, current encryption algorithms are considered to be very efficient, but it requires a lot of resources to handle this, which is expensive and time consuming. In addition, they also make the data impossible to process without first decoding. To be specific, traditional public key encryption requires data to be decrypted before it can be analyzed or manipulated. In contrast, homomorphic encryption is an encryption method that allows data to be encrypted while it is being processed and manipulated. It allows user or a third party, which can be cloud provider, to apply functions on encrypted data without revealing the data's values. In this paper, we explore existing multi-cloud-based security solutions using homomorphic encryption to identify open issues and opportunities for further enhancement.

Introduction

Cloud computing and related technologies are currently attracting a lot of attention from either research or industry. Michael Armbrust et al [START_REF] Armbrust | Above the clouds: A berkeley view of cloud computing[END_REF] define the cloud as "the long-held dream of computing as a utility". The National Institute of Standards and Technology (NIST) gives another definition [START_REF] Peter | the nist definition of cloud computing[END_REF] "cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction." The cloud computing paradigm can be described in simple terms as "everything as a service", where data is accessible over the Internet. The most popular ones are Platform as a Service (PaaS), Infrastructure as a Service (IaaS) and Software as a Service (SaaS). The advantages of cloud computing are undeniable, such as lower computing costs, instant software updates, reduced software costs, and unlimited storage. The multicloud service is the next generation in cloud computing's development. The necessity to integrate clouds for enhanced processing and storage capability has become an increasingly relevant subject for IT experts as resource requirements seem to be increasing inexorably. Concerns regarding vendor dependency and cloud failure have also been highlighted, both of which might be mitigated by switching to a multi-cloud environment [START_REF] Abu-Libdeh | Racs: a case for cloud storage diversity[END_REF]. A multi-cloud approach is a cloud storage architecture that creates a virtual cloud storage system by combining several cloud storage providers. The data to be saved is divided into separate blocks and redundantly distributed to numerous cloud storage providers. However, collaboration with multiple clouds raises security concerns such as increased attacks, loss of control over data and data privacy issues. To avoid this situation and protect data privacy in multi-cloud environments, one possible solution is to use fully homomorphic encryption (FHE) to ensure privacy. The goal behind FHE is to allow anyone to use encrypted data to perform useful operations without accessing the encryption key. In particular, this concept has applications to improve cloud computing security. In case, a user wants to store sensitive, encrypted data in the cloud but does not trust her cloud provider or is at risk of an instruder breaking into her cloud account or application, FHE provides a way to pull, search, and manipulate data without having to allow the cloud service provider access to the data. Generally, homomorphic encryption is an encryption scheme that allows computations on encrypted data and obtains an encrypted result when decrypted produces the same result of computations on the original data. The aim of this work is to offer an architectural framework to help in securing data sharing processes in a multi-cloud context. To be specific, the paper highlights the ways of achieving secure data sharing through the application of homomorphic encryption. In the next section, we will survey the state of the art on homomorphic encryption and we will explore what are the main challenges to tackle in real applications for multi-cloud architecture. Section 3 provides a detailed description of multi-cloud computing privacy challenges using homomorphic encryption. Introducing the main contribution that describes a new architecture proposed for the multi-cloud electronic medical records, can be found in Sect. 4. Finally, conclusions are summarized in Sect. 5.

Related works

To enhance security and privacy in the cloud environment, many studies have tried to use different encryption methods to develop the most optimal solutions. Cloud computing security consists of two areas: security issues encountered by cloud providers (organizations that provide software, platforms or infrastructure) and security issues faced by customers. Innovations and new technologies are fully applied in each part. Therefore, in this section, we conduct a review of the state-of-the-art of different forms of cloud security and try to find out what advantages and insufficiencies exist in current approaches.

In [START_REF] Ameur | Secure and non-interactive-nn classifier symmetric fully homomorphic encryption[END_REF], the authors brings a solution for the K-nearest neighbors (k-NN) algorithm with a homomorphic encryption scheme (called TFHE). The proposed solution addresses all stages of k-NN algorithm with fully encrypted data, including the majority vote for the class-label assignment. Unlike existing techniques, the solution does not require intermediate interactions between the server and the client.

In MCC context, the authors [START_REF] Louk | Homomorphic encryption in mobile multi cloud computing[END_REF] discuss the security of mobile multi-cloud computing (MMC) and the advantages for the mobile user(s). They highlight security issues in Mobile Cloud Computing and the main reason to move to multi-cloud. Similary, the light token has been introduced in [START_REF] Thinh Le | Property based token attestation in mobile computing[END_REF] to secure the mobile user in MCC environment. In this approach, the authors introduced a novel attestation schema based on the existing attestation mechanism as well as traditional enscryptions. Although the stability of the algorithm has been verified, this approach was based on trusted parties, which makes it difficult to control data and privacy. With other approaches, Fabian et al. [START_REF] Fabian | Collaborative and secure sharing of healthcare data in multi-clouds[END_REF] suggested an architecture for exchanging health care information using Attribute Based Encryption and cryptographic secret sharing. This technique does not ensure the data integrity or efficiency of the full process, which includes uploading, file slicing, and group sharing, among other things. In [START_REF] Zkik | Secure scheme on mobile multi cloud computing based on homomorphic encryption[END_REF], the authors present a security platform that allows user authentication and data encryption. The platform uses the properties of homomorphic encryption to generate a robust electronic signature. Then to improve the authentication mechanism, the verification tasks are distributed over different virtual machines so that an attacker can never recover or intercept passwords or other personal information of the data subject. In the work of Zibouh et al. [START_REF] Zibouh | Cloud computing security through parallelizing fully homomorphic encryption applied to multi-cloud approach[END_REF], a multi-cloud architecture has been proposed with fully homomorphic encryption by using the gentry scheme [START_REF] Gentry | Fully homomorphic encryption using ideal lattices[END_REF] to enhance the performance and the time of data processing. However if the size of the file increases, computation overhead arises.

Multi-cloud computing privacy challenges using homomorphic encryption

Multi-cloud has many advantages for the security of user data in cloud computing. Multi-cloud security is one of the concerns that requires a lot of attention. Many researchers and industry professionals debate on security challenges such as isolation management, data exposure and confidentiality, VM security, trust, and special security risks linked to the cooperation between cloud entities. Trust, policy, and privacy, in particular, are key considerations in multicloud systems. We will focus on the customer data protection and identity in this proposal. Cloud data privacy is critical because sensitive customer information should not be shared with anyone who is not authorized to access it. When data is stored in many clouds, there should be a method in place to protect data privacy and identification. When the volume of data is extremely sensitive, clients must disguise their identification traits from Cloud computing services in order to maintain anonymity. To protect unwanted access during data transportation and storage in cloud systems, appropriate data encoding techniques should be utilized.

Literature review of homomorphic encryption

This new encryption paradigm allows any entity (for example, the cloud provider) to operate on private data in encrypted form without ever decrypting it. The goal of Homomorphic Encryption (HE) is to perform operations on the plain text while manipulating only ciphertexts. Usually, we must decrypt them and then apply the desired processing to manipulate encrypted data. For example, one widespread use case is outsourcing healthcare data to cloud computing services for medical analyses.

More formally an ecryption scheme is called homomorphic over an operation * if it supports the following equation:

E(m 1 ) * E(m 2 ) = E(m 1 * m 2 ) ( 1
)
where E is the encryption algorithm and M is the set of all possible messages.

According to [START_REF] Albrecht | Homomorphic encryption security standard[END_REF] Homomorphic encryption schemes can be standardised by four algorithms:KeyGen,Enc,Dec and Eval. KeyGen generates a pair (public key, private key) for the assymetric configuration and (private key) for the symmetric version. Enc is the encryption algorithm and Dec is the decryption algorithm.

These three algorithms (KeyGen,Enc,Dec) are common to other conventional cryptosystems, otherwise in homomorphic encryption schemes an additional algorithm is needed, the Eval algorithm defined as follows:

Eval( f, C 1 , C 2 ) = f (M 1 , M 2 ) where Dec(C 1 ) = M 1 and Dec(C 2 ) = M 2 (2)
For some cryptosystems with algebraic structures, some operations are possible. For example, two RSA ciphertexts can be multiplied to obtain the multiplication of the two corresponding plain texts. We call this property the multiplicative homomorphic property of the "textbook RSA" cryptosystem. Another operation can also be performed on ciphertexts. For example, in the Paillier cryptosystem [START_REF] Paillier | Public-key cryptosystems based on composite degree residuosity classes[END_REF], we can add two ciphertexts to obtain the addition of the two corresponding plain texts. We call this property the additive property of the "Paillier" cryptosystem. For example, this can be useful when we are interested in e-voting applications to add encrypted votes without knowing the initial vote.

Rivest, Adelman and Dertouzos first introduced the notion of homomorphic encryption in [START_REF] Rivest | On data banks and privacy homomorphisms[END_REF]. Building a cryptosystem with both multiplicative and additive properties was a significant problem in cryptography, until the work of Gentry [START_REF] Gentry | Fully homomorphic encryption using ideal lattices[END_REF]. Gentry proposed a first Fully homomorphic encryption based on ideal lattices. The HE is categorized depending on the number of mathematical operations performed on the encrypted message as following: Partially Homomorphic Encryption (PHE), Somewhat Homomorphic Encryption (SHE), and Fully Homomorphic Encryption (FHE).

When operations are performed on ciphertexts, the noise increases and too much noise disables accurate decryption. The bootstrapping approach is used by FHE systems to get around this as stated in [START_REF] Gentry | Fully homomorphic encryption using ideal lattices[END_REF]. Bootstrapping decreases the collected noise, allowing further computation. This procedure can be done as many times as necessary to analyze any particular circuit. However, bootstrapping is computationally costly, so many solutions do not employ it in reality. Therefore, we recommend the reader to refer to [START_REF] Acar | A survey on homomorphic encryption schemes: Theory and implementation[END_REF] for more detailed information on the different homomorphic encryption schemes. We have chosen not to describe the entire functioning of cryptosystems due to the lack of space. Also, selecting secure and efficient instantiations of the underlying cryptographic problem is hard for most of encryption and homomorphic schemes. As with Curve Cryptography, post-quantum encryption, and many other standardization initiatives, new cryptographic concepts take a few years to achieve general adoption in the industry. FHE is only appropriate for single-user calculations since it needs inputs to be encrypted with the same key. However, there is a variety of scenarios in which users who have uploaded their big data stores to the cloud in encrypted form decide to calculate a joint function of their combined data. They may, for example, want the cloud to calculate joint statistical information on their databases, discover common files in their collections, or operate a computational agent to make a decision based on their pooled data (without disclosing anything but the final judgment).

Multi-key Homomorphic encryption

López-Alt et al. [START_REF] López-Alt | On-the-fly multiparty computation on the cloud via multikey fully homomorphic encryption[END_REF] proposed the first multi-key homomorphic encryption,a system to provide a homomorphic evaluation on ciphertexts encrypted with various keys. Unlike general HE schemes, this kind of HE scheme eliminates the necessity for a key setup step prior to any computation to build a joint key from individual keys. Instead, a cloud evaluator may dynamically convert ciphertexts from encryption using individual keys for encryption using the concatenation of individual users' keys.

We have proposed a solution using the following scheme [START_REF] Hao Chen | Multi-key homomorphic encryption from tfhe[END_REF], named MK-TFHE scheme, a first implementation in the literature to implement an MKHE scheme.which is defined by seven probabilistic polynomial-time (PPT) algorithms:

•

Our contribution

To further enhance data privacy and reduce the amount of calculations, we proposed more secure system models by adding more clouds.

Many challenges need to be tackled to apply homomorphic encryption in multi-cloud real-world applications. We have identified the multi-key homomorphic encryption [START_REF] Aloufi | Computing blindfolded on data homomorphically encrypted under multiple keys: A survey[END_REF] or the multiparty extenstions "Threshold setup" of the library OpenFHE [START_REF] Al Badawi | Openfhe: Open-source fully homomorphic encryption library[END_REF] for BGV, BFV, and CKKS schemes, to use them in a multi cloud setup.

We introduce and describe a new architecture proposed for multi-cloud electronic medical records as in Fig. 2. This model uses homomorphic encryption algorithms to ensure individual privacy in network and multi-cloud environments. The advantage of our proposal is that it is based solely on OpenFHE, a reference open-source library in the field of homomorphic encryption, and can be easily configured by neophytes. We performed simple homomorphic operations to prove the feasibility as it is depicted in the next sub-sections.

Experimental evaluation

We make some experiments in order to evaluate the performance and the usability aspects on a variety of applications of multi-key and multiparty extenstions "Threshold" of homomorphic encryption. In the multi-cloud environment, we use OpenFHE [START_REF] Al Badawi | Openfhe: Open-source fully homomorphic encryption library[END_REF] for Homomorphic Encryption and DepSky as a multi-cloud platform.

OpenFHE: Open-Source Fully Homomorphic Encryption Library

We use OpenFHE [START_REF] Al Badawi | Openfhe: Open-source fully homomorphic encryption library[END_REF] to implement the homomorphic encryption scheme, a new open-source FHE software library that integrates a variety of innovative design concepts from previous FHE libraries such as PALISADE, HElib, and HEAAN. OpenFHE supports various FHE schemes and hardware acceleration backends using a standard Hardware Abstraction Layer (HAL). OpenFHE supports both user-friendly and compiler-friendly modes, with the library automatically performing all maintenance operations such as modulus switching, key switching, and bootstrapping. We choose to use a multi-key homomorphic encryption scheme [START_REF] Hao Chen | Multi-key homomorphic encryption from tfhe[END_REF], a cryptosystem that allows us to evaluate an arithmetic circuit on ciphertexts, possibly encrypted under different keys.

DepSky: Multi cloud computing platform

We experiment with our proposal by using DepSky [START_REF] Bessani | dependable and secure storage in a cloud-of-clouds[END_REF] with local storage, a multi-cloud platform that enhances the integrity, confidentiality, and accessibility of data stored in the cloud. This is accomplished by creating a cloudof-clouds by encrypting, enclosing, and replicating all the data across a number of separate clouds. This architecture addresses the single cloud's limitations by replicating all of the data in a set, the availability issue of clouds and as a result the data can be retrieved correctly even if some of the clouds corrupt or lost data. It addresses the loss and corruption of data issue by using Byzantine fault-tolerance replication to store data in multi-clouds. It addresses the loss of confidentiality issue by employing a secret sharing schema and erasure codes to ensure that all data that will be stored in a multi-cloud environment are encrypted.

The Health-Care Use-Case

Nowadays, the application of multi-cloud environment is more and more widespread. Multi-cloud environment is applied in many different aspects such as information communication, vehicle systems and medical health systems. While people are paying more and more attention to their medical health, their medical data considered as sensitive must be handled in a secure way like shown in Fig. 1.

Several health-care activities using EHRs (Electronic Health Records) are an attractive use-case for multi-provider cloud in the healthcare industry: data access by the patients, prescription management application for doctors or other institutions, and assisted surgery.

The protection of personal health data is a major issue. Indeed, these data can lead to the covetousness of malicious parties with the aim of generating profits [START_REF] Pussewalage | A patient-centric attribute based access control scheme for secure sharing of personal health records using cloud computing[END_REF]. The three fundamental and main goals of security are: confidentiality, integrity and availability.

• Confidentiality: Only an authorized person should have access to the information.

• Integrity: Information should be correct, and an unauthorized person should not alter it.

• Availability: Information should be accessible, available, and usable at any time but only by an authorized entity.

Architecture Model

Because many applications may use sensitive data that are distributed over multiple clouds, in our proposal, we propose a new architecture model that is based on homomorphic encryption in a multi-cloud environment. By combining these two paradigms, we design an architecture model which can ensure the security and the privacy of the users. The proposed architecture for our proposal is summarized in Fig. 2.

Detailed experimental results

Our solution has been implemented using OpenFHE and DepSky, and tested on Linux Ubuntu 64-bit machine with i7-7700 CPU 3.60GHz with four clouds.

The advantage of our architecture is that it is possible to choose among several homomorphic encryption schemes depending on the needs of homomorphic operations. We did our simulation using four local clouds, nevertheless, it is easy to deploy by choosing a commercial cloud like Amazon S3, Google Storage, RackSpace Files or Windows Azure Storage.

For security parameters, we have used the recommended parameters [START_REF] Hao Chen | Multi-key homomorphic encryption from tfhe[END_REF]. To show the feasibility of a homomorphic computation on a multi-cloud service we have applied simple operations such as an addition or a multiplication between two integers, the results obtained are presented in Table 2.

The results obtained are promising compared to those obtained with a mono-cloud service, because indeed the multi-cloud architecture allows to make parallel calculations over multiple data encrypted with multiple keys, with an additional negligible cost when we perform the decryption operation using the concatenation of individual user's keys.

It would now be interesting to test more complex operations such as applying machine learning algorithms on health data by using homomorphic encryption [START_REF] Ameur | Application of homomorphic encryption in machine learning[END_REF].

Conclusion

Despite the benefits of cloud applications for healthcare, cloud security challenges must be addressed. In this paper, we introduce and describe a proposed new architecture for Electronic Health Records with Multi-Clouds. This model will ensure the privacy of people in a network and multi-cloud environment using a multi-key homomorphic encryption algorithm. The advantage of our proposal is that it is based only on an opensource library "OpenFHE" that is a reference in the field of homomorphic encryption, and the configuration is easy for a non-expert. We have performed simple homomorphic operations to prove the feasibility. However, it would be interesting to explore other types of more complex operations, such as machine learning algorithms to know the contribution of the multi-cloud for the acceleration of the computation time.

Number of clouds time of one addition

  pp ← MK-TFHE.Setup(1 k ): This algorithm outputs public parameters pp given security parameter k • sk ← MK-TFHE.KeyGen(pp): This algorithm randomly generates secret key sk given the public parameters pp. • ct ← MK-TFHE.Encrypt(m,sk): This randomised algorithm encrypts message m with secret key sk and outputs ciphertext ct=(b,a). • (ct * , T * ) ← MK-TFHE.Pre-process (ct=(b,a 1 ,...,a ki ),T=id 1 ,...,id k ): This algorithm basically extends the input ciphertext with additional 0's in order to be able to perform the homomorphic operation over all the underlying k keys. • ct * ← MK-TFHE.Eval(C,ct * ): This algorithm evaluates circuit C over the l ciphertexts ecrypted with multiple keys. • u i ← MK-TFHE.PartialDecrypt(a * i , sk id i ): This algorithm takes as input a * i from ciphertext ct * corresponding to the party holding secret key sk id i and outputs a partially decrypted information u i • m ′ ← MK-TFHE.Merge(b, u 1 , ..., u k ): This algorithm takes as input all the partial decryptions derived from a ciphertext ct * and outputs the final plaintext m

′

Fig. 1 :

 1 Fig. 1: "Healthcare monitoring with a single cloud."

Table 1

 1

	describes the parameter used for our experimentation.
		LWE		RLWE
	n	α	B	d N	β
	560 3.05*10ˆ{-5} 2ˆ2 8 1024 3.72*10ˆ{-9}

Table 1 :

 1 Recommended parameter settings for our MKTFHE scheme: n, α and N, β denote the dimension and the standard deviations for LWE and RLWE ciphertexts to achieve at least 110-bit security level

  Time of a multiplication Blind rotation key Key-switching key

	1	63 µs	1200 µs	0.62 MB	70.3 MB
	2	48 µs	580 µs	0.82 MB	79.1 MB
	4	25 µs	320 µs	1.03 MB	95.1 MB
	8	15 µs	203 µs	1.33 MB	100.3 MB
	16	9 µs	124 µs	1.62 MB	120.2 MB

Table 2 :

 2 Results obtained of the calculation time of an addition and a multiplication by varying the number of clouds, with the size of the blind rotation key and the key-switching key