emphasizing transparency) makes it difficult for
universal privacy policies to fit all, but the complexity
of privacy policies increases users' cognitive burden
(Wang et al., 2021) (McDonald & Cranor, 2008).
Existing achievements demonstrate that a single
technical or design perspective is difficult to address
systemic contradictions, and there is an urgent need
to construct an integrated framework that conforms to
user needs, technical guarantees, and platform
collaboration.
This paper aims to propose a user-centered multi-
platform privacy protection framework, achieving a
coordinated optimization of security and experience
by dynamically balancing privacy strength and
functional requirements. Firstly, it analyzes the core
challenges in multi-App interaction. Then, based on
the Privacy by Design (PbD) principle, it integrates
hierarchical encryption, federated learning, and
dynamic permission control technologies to design a
lightweight protection scheme (Cavoukian, 2009).
2 CHALLENGES IN MULTI-APP
INTERACTION SCENARIOS
Under the multi-platform human-computer
interaction environment, data sharing and functional
synergy among different applications (APPs) for
users have brought considerable convenience;
however, they also given rise to a series of privacy
protection issues.
Firstly, data sharing among different Apps relies
on third-party interfaces, but the differences in
technical standards and encryption protocols between
platforms lead to the risk of data leakage. For instance,
when users authorize login to JD.com through
WeChat, their data must be transmitted between
platforms. If there are vulnerabilities in the third-
party interface, the data may be maliciously
intercepted or misused (Cavoukian, 2009). A notable
example is the 2018 Facebook-Cambridge Analytica
incident that required a third-party application to
illegally obtain data of 87 million users through the
social graph, exposing the systematic pitfalls of cross-
platform data flow (Tencent, 2022).
Secondly, in a multi-App environment, users need
to configure privacy permissions for different apps
individually, leading to increased operational
complexity. For example, navigation Apps request
"always allow" location access, whereas social
platforms only request them "when in use". However,
users have difficulty understanding the difference in
permissions and potential risks (Isaac & Frenkel,
2018). Research shows that over 60% of users accept
all requests by default due to permission prompt
fatigue (Lin et al., 2022). More seriously, malicious
Apps can also infer user information through
permission combinations.
Finally, there exist significant differences in users’
cognition of privacy risks, making it challenging to
adapt consent protection strategies. Young users pay
more attention to functional convenience and tend to
open social data to obtain personalized
recommendations; while elderly users have higher
requirements for privacy transparency and are
reluctant to share data due to concerns about risks. In
addition, users often overlook key terms due to overly
complex privacy policies, which exacerbates the risk
of privacy leakage (Schaub et al., 2019).
3 USER-CENTERED PRIVACY
Privacy by Design (PbD), proposed by Anne
Cavoukian, is a systematic methodology that
emphasizes embedding privacy protection into the
design stage of products, systems, and services rather
than addressing it as an afterthought (Cavoukian,
2009). Its core lies in achieving privacy protection
throughout the entire life cycle through seven
principles, as illustrated in Figure 1: First, Proactive
not Reactive, such as Blue Orange Digital’s use of
machine learning to proactively identify risks; second,
Privacy as Default, minimizing data collection by
default and requiring user authorization; third,
Privacy Embedded, integrating privacy
technologies(e.g., encryption, anonymization) into
the system architecture; fourth, Full Functionality,
balancing privacy with other functional requirements;
fifth, End-to-End Security, ensuring the security of
data collection, storage, processing, and destruction
throughout the entire process; sixth, Visibility and
Transparency, clearly informing users of data usage
and open supervision; seventh, Respect for User
Privacy, granting users control over their privacy.
These principles, are centered on user rights and
interests, requiring enterprises to deeply understand
user needs and transform privacy protection into an
intrinsic feature of the product rather than an
additional function, thereby achieving a sustainable
balance between technological innovation and
privacy compliance.