###### Abstract  
Assistive robotic systems could be a suitable solution to support a variety of health and care services, help independent living, and even simulate affection, to reduce loneliness. However, adoption is limited by several issues, as well as user concerns about ethics, data security, and privacy. Other than the common threats related to internet connectivity, personal robotic systems have advanced interaction possibilities, such as audio, video, touch, and gestures, which could be exploited to gain access to private data that are stored in the robot. Therefore, novel, safer methods of interaction should be designed to safeguard users' privacy. To solicit further research on secure and private multimodal interaction, this article presents a thorough study of the state-of-the-art literature on data security and user privacy in interactive social robotic systems for health and care. In our study, we focus on social robotics to assist older people, which is a global challenge that is receiving a great deal of attention from the robotics and social care communities. This application will have a significant positive impact on the economy and society, but poses various security and privacy issues. This article analyses the key vulnerable areas where data leakage could occur during a multimodal interaction with a personal assistive robotic system. Thus, blockchain with a resource-aware framework, along with a continuous multifactor authentication mechanism, are envisaged as a potential solution for making such systems secure by design; therefore, increasing trust, acceptability, and adoption. Among the key cybersecurity research challenges, it is crucial to create an intelligent mechanism that autonomously determines the right trade-off between continuous user prompts and system usability, according to data types and personal preferences. assistive technology; multimodal interaction; social robotics; privacy; security +
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provision of human-like affection [11]. However, this technology has several issues and concerns pertaining to its acceptance with respect to ethics [12; 13; 14]. In addition, intelligent social robots that implement conversational agents have issues pertaining to users' data privacy [15], which also affect the users' physical, social bonding, psychology, and social privacy [16]. Moreover, in general, even simple patient monitoring systems and devices, need to be secure and preserve users' privacy [17]; therefore, so much more is required for an effective assistive robotic system. To show the global dimension of the issue, Table 1 provides the ageing population distribution of the world, which will be more than doubled in the next thirty years; thus, the current problems will be amplified. As per the United Nations, Department of Economic and Social Affairs, Population Division (2019) [18], in Europe and Northern America many older people prefer to live independently (unlike other subcontinents such as Asia, Africa, and Latin America, where the older prefer to live with their children) and this is where we predict that socially assistive robotic systems could become most popular, to support and provide necessary assistance to promote independent healthy living. Given all the required functionalities, a human-like appearance and the technical ability to provide required services may not be sufficient for acceptance and use of multimodal social robotics among health and care digital assistants. One of the other biggest questions is _Can we trust the machines?_ Indeed, level of trust has a significant impact on how much users comply with artificial agents [19], which is critical in medicine, as low compliance with prescriptions can cause adverse outcomes for patients' health. This article focuses on social and care assistive multimodal robots' security and privacy issues.