# A Review of Blockchain Technology Applications in Ambient Assisted Living
## 3 Results
### Security and Privacy  
Blockchain technology usage in ambient assisted living systems brings benefits (see Table 5) for addressing flaws and vulnerabilities, such as security flaws in smart IoT devices [41], trust and security, as well as the interoperability of such systems with legacy applications [20]. It may also circumvent the restrictions of client/server architectures in cloud-based ambient assisted living applications because of its scattered peer-to-peer nature [13]. A thorough literature review of GDPR-compliant blockchains was conducted in [32]. The essential GDPR for blockchains can be broken down into six categories that include data removal and modification, security by design, data controller and data processor obligations, consent management [35], data processing norms and lawfulness, and geographical reach. In [79], new research paths are proposed, such as the adoption of private blockchains to support the implementation of ambient assisted living systems. The authors of [41] examined recent breakthroughs in IoT-based healthcare procedures identifying critical challenges for systems development such as security, privacy, and authentication. In [43], blockchain technology was utilized to address such challenges to build a more efficient and dependable care system. Additionally, blockchain provides relevant features for ambient assisted living systems, such as data tampering and service failures [78]. Utilizing a distributed ledger, data might be visible to all users and, therefore, would allow for data integrity and provenance tracking verification [92]. In [35], a thorough assessment of the implementation of blockchain technology in the sphere of consent is presented, as well as privacy and data management. The consent of the patient is an important topic in the field of ambient assisted living systems [50]. In [60], a \begin{table}
\begin{tabular}{c c c} \hline \hline
**Ambient Assisted** & **Blockchain Usage** & **References** \\
**Living Use Case** & & \\ \hline \multirow{4}{*}{
\begin{tabular}{c} AAL system security \\ and privacy \\ \end{tabular} } & GDPR compliant applications & [32; 35; 78; 79] \\  & Informed consent management & [14; 21; 27; 35; 50; 56; 58; 60; 99; 100; 101] \\ \cline{1-1}  & Data privacy and & \\ \cline{1-1}  & identity management & [13; 15; 29; 45; 50] \\ \cline{1-1}  & Security and confidentiality & [20; 22; 27; 30; 50; 80; 93] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Blockchain usage benefits for the security and privacy of AAL systems. study was conducted on better techniques to manage informed consent so that data access is not abused and personal data protection regulations are respected. A good platform for obtaining informed consent from both a patient and a proxy (in the case of patients who have no discernment or cannot make decisions for themselves) is the Hyperledger fabric network blockchain [27] with smart contracts. Blockchain platforms may combine several roles and stakeholders in the care system, such as institutions that regulate access to personal data, data consumers, research institutions such as universities, and devices and technologies that acquire data [98]. A consent management framework that incorporates Distributed Ledger Technologies is presented in [21]. The platform offers an onion-layered secure way of transmitting sensitive data and a better way of accessing management methods. IPFS can be used for sharing files in a safe, transparent, and decentralized way in ambient assisted living systems [14]. Similar solutions based on another type of blockchains can be found in the literature [99], but they are not focused directly on consent, even if they can be interpreted as access to data itself [100]. Lately, differential privacy has emerged as perhaps the most successful privacy guarding solution for IoT medical and care infrastructure [13].