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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Data Privacy in Smart Home Devices</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Natalia Khetagourova</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Christofer</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Lundh</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Joakim Kävrestad</string-name>
          <email>joakim.kavrestad@ju.se</email>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Data Privacy</institution>
          ,
          <addr-line>IoT Security, CE Self-Declaration, RED Directive, Smart Home, Regulatory Compliance, Penetration</addr-line>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>School of Engineering, Jönköping University</institution>
          ,
          <country country="SE">Sweden</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2025</year>
      </pub-date>
      <abstract>
        <p>This research critically evaluated smart-home IoT-devices' data privacy and security practices Devices that selfdeclare CE compliance under EU RED directive 2014/53/EU were included. In response to escalating consumer risk due to unverified self-certification, a mixed-methods framework combining penetration testing, encryption analysis, and document analysis was applied to assess eight devices sold by European and Chinese retailers. The ifndings reveal a disparity in encryption standards, data transmission transparency, and compliance with EU expectations. European devices generally demonstrate stronger security configurations, while many Chinese devices expose users to significant privacy threats, including unauthenticated API use and third-party data routing. This study identifies systemic regulatory gaps in CE-mark enforcement and suggests mandatory thirdparty certification, increased transparency obligations, and regular legislative reassessments to bolster consumer protection in the evolving IoT ecosystem.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Testing</p>
    </sec>
    <sec id="sec-2">
      <title>1. Introduction</title>
      <p>This research examines how Internet of Things (IoT) devices manage user data and privacy, concentrating
on variations based on a retailer’s region of origin. It seeks to ofer insights into IoT architecture, data
privacy practices, and the eefctive</p>
      <p>use of connected technologies. In this research, we consider the
security and privacy of IoT devices from a socio-technical perspective [1]. As been argued for in
previous research [2, 3, 4], both cybersecurity and the IoT ecosystem are dependent on technology
as well as the individuals and organizations where they are present. Further they are impacted by
regulatory frameworks. Given the socio-technical perspective, the security and privacy on IoT devices
are dependent in the interplay between those aspects [5]. In this research, we focus on the interplay
between regulatory and technical aspects of security and privacy in IoT devices.</p>
      <sec id="sec-2-1">
        <title>1.1. Problem statement</title>
        <p>The global IT market is projected to reach 40 billion devices by 2030. Escalating cybersecurity risks
accompany this growth; [6] reported a 400 % increase in IoT-targeted cyberattacks in 2023, noting that
many smart home devices predominantly use insecure plain text communications (only 14.03 % used
SSL/TLS) [7, 8]. In response to these threats, governmental agencies such as the European Union (EU)
have enacted regulatory legislation to protect consumers. The CE-Marking (Conformité Européene) is
mandatory for products marketed in the EU, and is used to indicate compliance with safety, health, and
environmental standards. For IoT devices, CE-marking includes compliance with the Radio Equipment
Directive (RED) 2014/53/EU, specifically</p>
        <sec id="sec-2-1-1">
          <title>Article 3(3)e, which mandates safeguards for user personal data and privacy protection [9, 10, 11]. Despite these regulations, the market is increasingly flooded with inexpensive Smart Home devices from Chinese online marketplaces [12]. The CE assessment is self-declaratory, relying on manufacturers’ integrity [13]. Recent incidents, such as the FBI dismantling</title>
          <p>CEUR
Workshop</p>
          <p>
            ISSN1613-0073
a botnet of 200,000 IoT devices linked to the People’s Republic of China (PRC)[14], highlight the risks
consumers face from potentially non-compliant devices, which contribute to cybersecurity threats
regardless of their point of purchase. This experimental study compares IoT devices from oficial
Swedish retailers against those from Chinese e-commerce retailers, evaluating their privacy and data
security against EU Directive 2014/53/EU Article 3(
            <xref ref-type="bibr" rid="ref3">3</xref>
            )e. This addresses whether consumers face similar
data and privacy risks irrespective of the retailer’s origin.
          </p>
        </sec>
      </sec>
      <sec id="sec-2-2">
        <title>1.2. Research questions</title>
        <p>Given the rapid increase in IoT devices and the reliance on self-declaration for CE marking, this study
aims to determine what happens to consumers’ data collected by smart home devices and examine
whether the level of privacy and security difers based on the point of purchase.</p>
        <p>
          Therefore, the research questions for this study were:
• [1] How is the user’s data and privacy managed and controlled in IoT devices?
This question addresses the issues of consumer trust and regulatory conformity by exploring
how collected consumer data is stored and managed in the devices. Furthermore, insights gained
from this analysis will provide evidence on whether manufacturers’ standards align with stated
EU expectations.
• 2] What diferences can be identified between the tested IoT devices of European and
Chinese products compared to the EU directive 2014/53/EU Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e?
Considering that the smart home market is saturated with afordable IoT devices sold by Chinese
e-commerce retailers, this question aims to identify the diferences between the IoT devices tested
in this study and EU Directive 2014/53/EU Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e. The assessment will involve penetration
testing the devices against the directive, clarifying whether the point of purchase afects the data
and privacy security level in those devices.
        </p>
      </sec>
      <sec id="sec-2-3">
        <title>1.3. Scope and limitations</title>
        <p>
          This study focuses on identifying potential regional variations in CE compliance among retailers (point
of purchase) rather than manufacturing standards, acknowledging that 32 % of all IoT devices are
manufactured in China [15]. The study follows explicitly to EU Directive 2014/53/EU, Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e,
concerning radio equipment and data/privacy safeguards. Specific radio equipment categories (e.g.,
child monitors, wearables) were excluded due to supplemental regulations. This study does not perform
a complete 2014/53/EU directive compliance assessment, excluding criteria beyond its scope (e.g.,
electrical, technical, safety standards). The methodology included penetration testing with simpler
network monitoring tools for acquiring security and compliance data for analysis without advanced
hardware manipulation. Furthermore, as the mobile phone used to enable the tests in this study was
an Android, it regularly communicated with various Google servers and domains, since there were no
appropriate ways to distinguish whether data sent to Google was related to IoT devices or the mobile
phone, that data was excluded from the results.
        </p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>2. Methodology</title>
      <p>The research employed an experimental methodology which in three steps assessed devices included in
this research. The experiment involved the following steps, and was repeated for each device:
1. Setup where we used a small network consisting of one computer, one mobile phone and the
device we were testing, all connected to a simple wireless network with an internet connection.
The general idea was to configure and manage the device using the cell phone, and to use the
computer to conduct the experiments as outlined in steps 2-4.</p>
      <p>Device name</p>
      <p>Ring Doorbell 5F97F2</p>
      <p>Deltaco SH-IPC16 Camera
Cleverio CCT LB200 smart lightbulb</p>
      <p>Cleverio Smart Mini Plug</p>
      <p>XW133-X9 Doorbell</p>
      <p>v380 Pro Camera</p>
      <p>Antela Smart Bulb E27
Tuya Smart Socket F-ES01W</p>
      <p>Device type</p>
      <p>Doorbell
Camera
Lightbulb
Smartplug
Doorbell
Camera
Lightbulb
Smartplug</p>
      <p>Retailer</p>
      <p>EU
EU
EU</p>
      <p>EU
China
China
China
China
2. Vulnerability assessment which involves identification of possible vulnerabilities that could be
exploited [16]. This step involved both identification of vulnerabilities listed in public sources
such as the CVE database [17], and using tools such at NMAP.
3. Penetration testing which involved attempts to use identified vulnerabilities to gain access to
the tested devices, or data they sent over the network. The Penetration Test and Data Analysis
Framework which is based on the IoT-PEN methodology for penetration testing of IoT devices
was used [18, 19].
4. Network analysis where we analyzed network data to investigate where data traveled when
being transferred between the mobile phone and the tested device.</p>
      <p>Each experiment was conducted in an isolated laboratory network designed to mimic an average
home network to ensure accurate and realistic data. Each device went through a BLE snifing attack
during setup while Wireshark was snifing network trafic, followed by port scans and
Man-In-TheMiddle (MITM) attack methods to intercept the data. Once the penetration and vulnerability section
of the experiment was completed and documented, the network analysis was initiated, focusing on
security implementations, peer-to-peer, cloud, regional domains, and network protocols.</p>
      <p>The collected data were then analyzed quantitatively and qualitatively, with a mixed methods analysis
to summarize the average of the results. The quantitative analysis focused on encryption strength,
data path transparency, and CE compliance rate, while the qualitative analysis focused on the devices’
primary vulnerability and data-sharing concerns.</p>
      <p>Since this thesis compares possible CE compliance diferences in data privacy and security
implementations between products sold by Chinese and European retailers, smart home devices in this study must
be comparable in their technical specifications and functions to be suitable. Functional equivalence
of the devices, such as video and voice communications, network connectivity, and associated mobile
applications, ensured that observed variations in security implementation were not based on product
category but on regional sales requirements. Eight devices in total were included in this research. They
covered four diferent functions and for each function, one Chinese and one European device was
included, as outlined in Table 1.</p>
    </sec>
    <sec id="sec-4">
      <title>3. Results</title>
      <p>
        This chapter presents the outcome of the experiments for each individual device, and the european
devices are presented first. While most devices demonstrated positive compliance with EU Directive
2014/53/EU, Article 3(
        <xref ref-type="bibr" rid="ref3">3</xref>
        )e, and implemented security measures, some exhibited minimal or no
security features, transmitting data via cloud servers across various regions before reaching the mobile
device. Our analysis focused on encryption, security implementations, API management, trafic routing,
and involved domains. By monitoring network behavior and identifying domain involvement, we
assessed the extent of third-party engagement, data management, and protection during device-to-device
communication, such as video calls.
      </p>
      <sec id="sec-4-1">
        <title>3.1. European devices</title>
        <p>3.1.1. Ring Doorbell 5F97F2
Ring Doorbell (Amazon Inc.) was analyzed for security and network practices. This device costs
approximately €100 and supports video, voice, and night vision. Network analysis revealed robust security
protocol implementation, including TLSv1.2, HTTPS, DTLSv1.2, and transport protocols like TCP, UDP,
QUIC, RTCP, RTP, and WebRTC for live streaming. Certificates were issued by Starfield Technologies
Inc. for internal communication and DigiCert for external communication with Amazon cloud servers.
The doorbell utilized RSA 2048 encryption and the TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
cipher suite, ensuring strong ephemeral session key generation. Both TLSv1.2 (device-to-cloud) and
TLSv1.3 (app-to-cloud) were employed, indicating modern encryption.</p>
        <p>Despite WebRTC enabling low latency, all device communications, including audio and video streaming,
were consistently routed through Amazon cloud servers, even when the doorbell and mobile phone
were on the same local network. STUN and TURN protocols and XOR-mapping for IP addresses
facilitated this cloud-centric routing. Authentication involved cloud-based username verification and
hashed fingerprints. STUN transactions were secured with HMAC-SHA1, and client usernames were
Base64 encoded. Strong authentication was enforced during setup, including two-factor authentication,
complex passwords, and email verification.</p>
        <p>The doorbell and app exclusively communicated with Amazon and Ring-owned domains for device
management, streaming, configuration, and analytics. No direct device-to-phone communication was
observed. A significant privacy concern arose from the discovery of interactions with Facebook servers,
suggesting potential data sharing by Amazon.
3.1.2. Deltaco SH-IPC16 Camera
The Deltaco SH-IPC16 Camera, manufactured by Deltaco (Sweden) and utilizing Tuya Inc.’s IoT
cloud platform, was analyzed. Initial Nmap scans identified an open IRC port (6668) running IRC
v7.95 alongside the Tuya IoT protocol. Despite the association of IRC with botnet activity, attempts
to exploit vulnerabilities using Searchsploit, Exploitdb, HexChat, Netcat, and Metasploit, including
Man-In-The-Middle and ARP spoofing, were unsuccessful in decrypting or intercepting trafic.
Encrypted SSL handshakes prevented key retrieval, indicating initial resilience to basic exploitation.
Network analysis via Wireshark revealed that when the phone and camera were on the same network,
most TCP trafic, including video streams, was relayed through Amazon cloud servers. All application
data and handshakes utilized TLSv1.2, with strong cipher suites
(TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 for Amazon and
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 for Tuya). However, a critical vulnerability
was identified: Tuya’s servers used self-signed certificates. This mandates the camera to accept them
without validation, or rely on certificate pinning, creating a significant risk for MITM attacks, where
an attacker could spoof a Tuya server to gain device access. When the phone and camera were on
separate networks, communication was routed via a Telenor internet relay, with video streams sent
as encrypted UDP. STUN packets were used for public IP determination and session keep-alives. All
captured packets were securely encrypted, and no unauthorized data destinations were detected in this
configuration. Minimal trafic was observed when the phone was idle or devices were on separate
networks, even with push notifications.</p>
        <p>A BLE snifing session during device pairing was unsuccessful, suggesting the camera used a built-in
access point (AP) for initial setup.
3.1.3. Cleverio CCT LB200 Lightbulb
The Cleverio CCT LB200 smart lightbulb (Kjell &amp; Company, Sweden; approx. €20) was analyzed. It
operates on the Tuya platform via the Smart Life app.</p>
        <p>Reconnaissance confirmed the lightbulb as a Tuya device, with an IRC service detected on port 6668.
However, this was identified as a proprietary Tuya device-to-cloud communication protocol, not
standard IRC. Despite attempts using Nmap, Searchsploit, msfdb, Wireshark, Bettercap, Telnet, Netcat,
and Metasploit (including IRC-specific and Yeelight library exploits), no exploitable HTTP, HTTPS,
SSL trafic, or vulnerabilities were found. Tuya’s secure architecture and reliance on encrypted TLS
(v1.2/1.3) communication efectively mitigated traditional MITM attacks, rendering tools like Burp
Suite inefective.</p>
        <p>Network Analysis (Same Network): Most trafic was TCP between the mobile phone and Amazon
cloud servers (Germany). Lightbulb-originated trafic included handshakes and TCP to US-based
Amazon cloud servers and lifeaiot.com. All application data and handshakes were secured with TLSv1.2
and TLSv1.3, employing strong cipher suites like TLS_AES_123_GCM_SHA256 (for lifeaiot.com and
Amazon) and TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (for eu.lifeaiot.com). Certificates
were legitimately issued by DigiCert. Despite strong encryption, data was observed leaving the local
network to multiple Amazon and lifeaiot.com servers (Germany, US), even for local control.
Network Analysis (Separate Networks): Trafic to the phone primarily originated from
Amazon cloud servers (TCP, TLSv1.2, TLSv1.3, and SSLv2), while outbound trafic from
thephone mostly went to various eu.lifeaiot.com servers (TCP, TLSv1.3 for application
data). Strong cipher suites (TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384,
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) and DigiCert-issued certificates were
consistently observed for these communications.</p>
        <p>A BLE snifer captured a plaintext session/recognition token during the initial pairing process, though
no further active BLE trafic was detected. This unencrypted token during pairing is a minor concern,
but no further vulnerabilities were identified in BLE trafic or across iOS/Android platforms.
3.1.4. Cleverio Smart Mini Plug
The Cleverio Smart Mini Plug (Kjell &amp; Company, Sweden; approx. €15), a Tuya device, was analyzed.
Initial reconnaissance revealed that TCP port 6668 was open, characteristic of Tuya devices, but uniquely,
it also exposed a Telnet-accessible service. Attempts to extract data via Telnet and Netcat were
unsuccessful due to the custom Tuya protocol. However, fuzzing the Tuya protocol (starting with \x55\xAA)
using Boofuzz successfully induced intermittent denial-of-service (DoS) attacks, temporarily freezing
the plug.</p>
        <p>Network Analysis (Same Network): DNS queries from the plug went to h3.iot-dns.com, while the
phone communicated with third-party CDNs like cdn5th.com and cloudfront.net. The plug also
connected to AWS EC2 instances in Germany and the UK. TLS handshakes utilized TLSv1.2 with the
TLS_PSK_WITH_AES_256_CCM cipher suite, indicating a reliance on pre-shared key (PSK)
authentication instead of more secure certificate-based methods.</p>
        <p>Alarmingly, an over-the-air firmware update was intercepted. While encrypted, the firmware lacked
digital signatures or certificate verification mechanisms. Analysis revealed clear-text code related to
Zigbee communication, power management, and relay handling. Encrypted TCP trafic was recorded to
and from China Unicom, a Chinese state-owned telecommunications operator, without a clear purpose
or user consent.</p>
        <p>Network Analysis (Separate Networks): Minimal encrypted cloud-bound trafic was observed. No
peer-to-peer communication between the plug and the phone was detected, confirming all functionality
is mediated by Tuya’s cloud servers.</p>
        <p>A plaintext identifier string, common to other Tuya products, was observed during BLE snifing. While
a stronger scanner might capture plaintext router credentials, the study’s tools could not confirm this.</p>
      </sec>
      <sec id="sec-4-2">
        <title>3.2. Chinese devices</title>
        <p>3.2.1. XW133-X9 Doorbell
The XW133-X9 is a Chinese-manufactured smart home doorbell with video, voice, and night vision
capabilities. It is cheap and popular, easily accessible by retailers like Amazon and Temu. With prices
ranging from €10 to €20, Temu was the point of purchase for this thesis.</p>
        <p>During the network analysis, we found multiple vulnerabilities, such as unencrypted trafic, plaintext
API, session keys, and video trafic. What made things interesting was the UDP video trafic, which
was plain text, where we could identify the beginning of a JPEG File Interchange Format (JFIF) header
and where the JFIF file ended. JFIF is a file format for pictures, and the fact that this was transmitted
without any form of encryption meant that we could use a Python3 script to hijack and extract image
data from the network communication between the doorbell and the mobile phone.
The script begins by identifying the JFIF header and locating the network interface and source port:
INTERFACE = "Local Area Connection* 10"
SRC_PORT = 10006
soi = buf.find(b'\xff\xd8\xff\xe0')
eoi = buf.find(b'\xff\xd9', soi)
The script then begins to listen and inspect each UDP packet from the selected network interface and
source port, and extract everything between the beginning of the JFIF header and the end of the JFIF
ifle in each packet. As it extracts frames from each packet, it will display and mirror the trafic on the
attacker’s computer, performing a live stream of the video footage in real-time, making this device
extremely vulnerable to MITM attacks and Spyware. This is demonstrated by a caputured videoframe
in Figure 1. The camera tracks movement in front of the device and sends an API call containing
information about the activity, such as movement, alarms, and network information. This call is sent
unencrypted with the API authentication token and could be extracted and manipulated similarly to
video hijacking through MITM attacks.</p>
        <p>The unencrypted trafic from the device was sent to cloud servers in the US region, especially towards
the following domains: stark-industries.solutions, and naxclow.com, directly from the doorbell, even
if the phone and doorbell were communicating on the same network. The application for receiving
video calls and general communication between the doorbell and phone was more secure regarding
encrypted trafic. However, it sent and received much trafic to and from China and the US. Even though
the trafic was encrypted through HTTPS, QUIC, and TLSv1.3, it sent and received trafic, data, and
API information from gac1.dcloud.net.cn. (CN), cm-10-178.getui.com. (CN), home.naxclow.com. (US),
zjtelecom.com.cn (CN).</p>
        <p>
          From the analyzed vulnerabilities and trafic behavior, the device was not compliant with EU Directive
2014/53/EU Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e.
3.2.2. V380 Pro Camera
The v380 Pro Camera, a Chinese-made smart camera (€17 from Temu), ofers motion detection, night
vision, 360-degree rotation, and two-way voice.
        </p>
        <p>Vulnerability assessment revealed critical security flaws despite some encrypted trafic (SSL, TLSv1.2
for handshakes, and UDP). API calls were sent in plaintext HTTP/1.0, using static identifiers, lacking
authentication, session handling, and encryption. This exposed sensitive information like alarm types,
developer IDs, hashed usernames, and passwords. Furthermore, commands like “DOWNGRD” and
“UPGRD” were present, raising concerns about potential firmware manipulation if session keys were
compromised. The static “macro-video IPC” User-Agent also enabled targeted attacks. While Nmap
scans showed filtered/open ports limiting external communication, a BLE snifer captured plaintext
identification tokens (“BMV956 61237) during setup. SSL stripping attempts were mitigated by
wellprotected TLS handshakes, requiring server private key retrieval for decryption.</p>
        <p>The camera’s sole root certificate was issued by its manufacturer, GuangZhou HongShi CA Inc.,
raising security concerns due to the absence of neutral third-party certification.</p>
        <p>Network analysis showed trafic routed from the camera to a China-based domain (95661237.nvdr.net)
via a public Oracle cloud server before reaching the phone. Numerous UDP and TCP packets were
sent directly to Alibaba Cloud Service in Singapore and China. While this data was encrypted (SSLv2,
TLSv1.2), its contents were indecipherable, and no European cloud servers were involved.</p>
        <p>
          Although the camera used encryption to protect personal data in transit, thereby partially fulfilling
EU Directive 2014/53/EU Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e, significant concerns remain due to plaintext API calls, the
manufacturer acting as its certificate authority, and all trafic being routed through non-European
manufacturer-controlled cloud servers before reaching the client’s mobile phone.
3.2.3. Antela Smart Bulb
The Antela Smart Bulb E27 (€24 from Temu), a Wi-Fi-enabled light bulb operating via the Smart Life
app, was analyzed.
        </p>
        <p>Reconnaissance (Nmap, Searchsploit, Metasploit) indicated it is a Tuya-based product, similar to the
Cleverio CCT LB200 light bulb, with an open IRC service on port 6668. This port uses a proprietary
Tuya cloud communication protocol. Despite multiple attempts using various exploit tools (Netcat,
Telnet, Metasploit, Yeelight Python3, Burp Suite, Hak5 Pineapple), no exploitable protocols efectively
mitigated traditional MITM attacks. A BLE snifer detected a plaintext session/identification token
during initial pairing, but no further BLE activity was recorded post-setup.</p>
        <p>Network Analysis (Same Network): DNS queries from the bulb went to h3.iot-dns.com.
Open ports 443 and 8883 across Tuya Smart servers (Amazon-hosted in Germany, Ireland,
and the US) were observed. TLSv1.2 handshakes were secured with robust cipher suites like
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (for a1-eu.lifeaiot.com via DigiCert) and
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (for CloudFront via GoDaddy).
3.2.4. Tuya Smart Socket F-ES01W
The Tuya Smart Socket (Shenzhen, China; approx. €6-€7, from Temu) is an afordable wall plug with
remote power and voice control (Alexa, Google Assistant).</p>
        <p>Vulnerability assessment revealed an open port 6668 running the proprietary Tuya protocol v7.95 for
secure device-to-cloud communication. Despite attempts to exploit common IRC vulnerabilities (e.g.,
UnrealIRCd) or perform banner leakage using Netcat and Telnet, no results were yielded. Similarly,
attempts to force communication through a self-hosted IRC server (Hexchat) and SSL stripping attacks
were unsuccessful, as all communication was encrypted with TLSv1.2.</p>
        <p>Network Analysis (Same Network): DNS queries from the plug went to a3.tuyaeu.com and
m2.tuyaeu.com, while the phone queried a1-eu.lifeaiot.com. Connections to these Tuya Smart servers
(Amazon-hosted in Germany) used TCP with TLSv1.2. A recorded TLSv1.2 handshake with
a1eu.lifeaiot.com utilized TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 cipher suite and
a DigiCert-issued certificate. The mobile phone also transmitted encrypted UDP packets for device
discovery, and peer-to-peer communication between phone and plug used TCP/TLSv1.2.</p>
        <p>Network Analysis (Separate Networks): The plug maintained encrypted TLSv1.2 connections
with Amazon-hosted Tuya cloud services. Another connection to an Amazon AWS Tuya Smart server
on port 443 was noted. Though no certificates were recorded for this connection, the TLS handshake
used the TLS_PSK_WITH_AES_128_CBC_SHA256 cipher suite, indicating use of PSK authentication.</p>
        <p>BLE snifing attempts were unsuccessful due to an apparent Bluetooth malfunction, with pairing
relying solely on Wi-Fi.</p>
        <p>Conclusion on security: Tuya Smart Socket demonstrated no exploitable vulnerabilities using
standard assessment techniques. TLSv1.2 encryption and Tuya’s proprietary protocol on port 6668
limited attack vectors. While the presumed Bluetooth malfunction and the use of PSK-based TLS (a
minor concern, but still present) were noted, no plaintext data was discovered, and the plug appeared
to be generally secure.</p>
      </sec>
      <sec id="sec-4-3">
        <title>3.3. Data analysis</title>
        <p>3.3.1. Quantitative analysis</p>
        <sec id="sec-4-3-1">
          <title>The quantitative analysis focused on three main categories:</title>
          <p>• Encryption Strength where the devices were scored based on how strong exnryption they use.
• Data-Path Transparency where devices were scored based on how they transkef data between
the device and the mobile phone controlling it.
• Compliance-Exploit Index which is a metric that reflects if the device could be compromised in
this text, and if it is compliant with the CE mark.</p>
          <p>Each device was scored in every category on a scale from 1 to 4; the score was then summarized by
calculating the average, median, and standard deviation. We then looked at regional diferences using
a Mann-Whitney U test on Encryption Strength and Data-Path Transparency. Finally, the
ComplianceExploit Index regional diferences were visualized through bar charts.</p>
          <p>The scores for each category were:
Encryption Strength:
1. No encryption, or legacy encryption.
2. TLSv1.0-1.1
3. TLSv1.2
4. TLSv1.3
Data-Path Transparency:
1. Cleartext
2. All trafic is routed via untrusted cloud servers.
3. Mixed peer-to-peer (P2P) and cloud via trusted European servers.
4. Direct P2P only.</p>
          <p>Compliance-Exploit Index:
1. Compliant and Not Exploitable.
2. Compliant and Exploitable.
3. Non-Compliant and Not Exploitable.
4. Non-Compliant and Exploitable.</p>
          <p>On average, European devices scored about one point higher than Chinese devices in encryption
strength and transparency. As the calculations below show, EU devices used stronger ciphers and more
direct data paths. However, there’s quite a bit of overlap (especially in the Chinese scores), as shown by
the standard deviations.</p>
          <p>Encryption Strength
• Europe
– Number of devices: 4
– Mean = 2.25
– Median = 2.5 (TLSv1.0-1.2)
– Standard deviation ≈ 0.96
– Number of devices: 4
– Mean = 3.25
– Median = 3.0 (TLSv1.2)
– Standard deviation = 0.50
Data-Path Transparency
• China
• Europe
– Number of devices: 4
– Mean = 2.25
– Median = 2.5
– Standard deviation ≈ 0.96
– Number of devices: 4
– Mean = 3.0
– Median = 3.0
– Standard deviation ≈ 0.82</p>
          <p>Because our sample was small (n = 4 per region), we applied the Mann-Whitney U test to compare
ranked scores without assuming a normal distribution, to see if European and Chinese devices difered
on Encryption Strength and Data-Path Transparency. For Encryption Strength, the test statistic was U
= 13.0 with P = 0.137; for Data-Path Transparency, U = 11.5 with p = 0.353. Both p-values exceed the
0.05 threshold, meaning we cannot rule out the possibility that the observed diferences occurred by
chance. In other words, although EU devices showed higher average scores, the evidence is insuficient
to conclude a real regional gap.</p>
          <p>
            As shown in Figure 2, 75% of European devices fall into Tier 1 (compliant and not exploitable) and
the remaining 25% into Tier 2 (compliant but exploitable), while none appear in the high-risk Tier 4
(non-compliant and exploitable). In contrast, Chinese devices split evenly between Tier 1 (compliant
and not exploitable) and Tier 4 (non-compliant and exploitable), with no devices in Tier 2 or 3. This
shows that although half of the devices meet compliance, the other half fail the directive and remain
exploitable, highlighting an apparent regional disparity in real-world security.
3.3.2. Qualitative analysis
The qualitative analysis was divided into three heatmaps: all devices, European devices, and Chinese
devices. Each heatmap presents a 5x3 matrix visualizing what security flaws exist and how those flaws
coincide with data-sharing practices. Each device was coded by its primary vulnerability (A-E) and
data-sharing category (
            <xref ref-type="bibr" rid="ref1 ref2 ref3">1-3</xref>
            ).
          </p>
          <p>Primary vulnerability:</p>
        </sec>
        <sec id="sec-4-3-2">
          <title>1. Plaintext trafic</title>
          <p>2. Insecure certificates
3. Insecure API / Cleartext Authentication tokens
4. BLE Pairing weakness
5. MITM / Interception</p>
        </sec>
        <sec id="sec-4-3-3">
          <title>Data-sharing category:</title>
        </sec>
        <sec id="sec-4-3-4">
          <title>1. No third-party domains</title>
          <p>2. Manufacturer cloud only
3. Multiple third-party domains</p>
          <p>As seen in the heatmaps above, most of the vulnerabilities appeared in devices from the Chinese
region. The most common vulnerability was insecure API calls or clear-text authentication tokens.
The most common data-sharing concern was multiple third-party domains involved in communication
between the device and the user’s mobile phone.
3.3.3. Analysis summary
To combine our quantitative and qualitative findings, we present a joint display that aligns each region’s
average scores, compliance-exploit proportions, and dominant vulnerability x data-sharing pattern in a
single table and heatmap.</p>
          <p>
            Table summarizes for Europe and China:
• Average Encryption Strength and Data-Path Transparency scores.
• Percentage of devices in each Compliance-Exploit tier (
            <xref ref-type="bibr" rid="ref1 ref2 ref3 ref4">1-4</xref>
            ).
          </p>
          <p>• Most common vulnerability and data-sharing combination.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>4. Discussion</title>
      <p>This chapter provides an overview of the study’s findings. It further discusses the study’s implications
and limitations and outlines its conclusions and recommendations.</p>
      <sec id="sec-5-1">
        <title>4.1. Results discussion</title>
        <p>Based on the results and discoveries, it is safe to say that a significant focus on security improvement has
been implemented over the last few years, from IoT devices having no security at all to manufacturing
companies such as Tuya improving security in most of their devices [20]. Some concerns still raise
crucial questions, which will be further discussed in this chapter.</p>
        <p>
          As the focus was on our research questions, which were:
1. How is the user’s data and privacy managed and controlled in IoT devices?
2. What diferences can be identified between the tested IoT-devices of European and Chinese
products compared to the EU directive 2014/53/EU Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e?
        </p>
        <p>Many diferent encryption algorithms and innovative security solutions were found from device to
device during the experiments. However, there have been a couple of outliers, such as a lack of security
in device communication, weak encryption methods, mobile application security implementations, and
questionable trafic routing.
4.1.1. Should the directive be changed?
The questionable trafic routing raises a fascinating and crucial question about the RED directive this
study is based on: ”radio equipment incorporates safeguards to ensure that the personal data and privacy
of the user and of the subscriber are protected”. As we have seen data from Chinese devices in this study
being routed from IoT devices to the manufacturer’s servers before it reaches the user’s mobile phone,
this opens privacy and security concerns. Still, as the trafic leaves the network encrypted, which
would equal the safeguards, it meets the directive’s requirements. A study conducted on 81 smart home
devices in 2019 showed that 72 devices shared data with third parties such as Amazon, Akamai, and
others that were completely unrelated to original manufacturer [21].</p>
        <p>
          The directive’s lack of update since 2014 and the rapid development of IoT devices and security
threats indicate that it appears vague and outdated due to its wording. Considering how rapidly the
IT world has been developing and expanding since 2014, ranging from smart home devices to AI and
machine learning, Directive 2014/53/EU Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e is a crucial directive in the European technological
infrastructure.
        </p>
        <p>With stricter regulations included in the directive, there would be less room for bypasses and
loopholes, which would increase the security and privacy of European citizens, and with the hope that
the European Union would regularly revisit any directives related to personal data and digital privacy,
considering the rapidly expanding development of technology.
4.1.2. Contemporary Research and Commercial Practice
During the experiment phase of this study, it became evident that the security practices of some of the
manufacturers have been updated and have become more secure. As discussed in previous chapters, IoT
devices and, by extension, Smart Home devices are often designed to be compact and operate eficiently.
Because of the structural nature of these devices, they usually have limited resources in processing
power, memory, and battery life. While there are several emerging solutions, most of them come with a
tradeof, making the results from the experiments even more interesting because we can see solutions
manufacturers have implemented to increase security in the devices within the structural limitations of
the devices themselves.</p>
        <p>By conducting experiments, we saw that most devices implement TLSv1.2 or 1.3 rather than SSL, a
significantly higher number than reported in previous research. Some devices use DTLS1.2 for video
and WebRTC+STUN/TURN to enhance security in real-time media transmission. This solution ofers
low-latency, end-to-end encryption with NAT traversal and per-session ephemeral keys that guard
against eavesdropping and replay attacks.</p>
        <p>Another example of good security practices observed was modern and robust cipher suites such
as ECDHE (Elliptic Curve Difie-Hellman Ephemeral), which leverages elliptic curve cryptography to
establish secure key exchanges eficiently, ECDHE provides forward secrecy by generating ephemeral
keys for each session, ensuring past session keys remain safe even if long-term keys are compromised
[22].</p>
        <p>During the network analysis phase, it was noted that almost all devices used certificates for server
authentication, which is standard practice for securing TLS/DTLS sessions. However, not all certificates
used independent validation (GoDaddy, DigiCert), making devices that utilize self-signed certificates
vulnerable to spoofing.</p>
        <p>
          In conclusion, while improved security in IoT devices is achievable, these enhancements often coexist
with less secure practices. Although most tested devices comply with CE mark requirements, the
protection and privacy of user data remain debatable [23]. This discussion sets the stage for the next
section, which explores the relevance of the CE mark, or at least certain aspects of it.
4.1.3. Relevance of the CE-mark
Although the EU directive 2014/53/EU article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e aims to protect personal data and user privacy in IoT
devices, this study’s findings raise questions about its practical value. While devices may utilize robust
and modern encryption protocols during transmission, this alone does not ensure user privacy from
downstream services where user data might be decrypted and processed. The integrity of the original
encryption is compromised if user data is sold or shared with third parties and becomes decrypted,
particularly if this occurs without proper oversight, leading to potential data leaks, as illustrated by
earlier examples in this study. The 2014/53/EU directive aims for consumer protection; however,
whether parts of the directive have shifted toward being more procedural than genuinely protective
raises philosophical concerns, especially given that the CE mark is self-declaratory. Does the intended
purpose of the 2014/53/EU Directive Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e maintain its value in light of the security gaps in data
transmission and the potential mishandling of user data thereafter?
        </p>
        <p>While this study has identified weaknesses in the CE mark, some reforms could be applied to
strengthen the CE mark in several ways. Based on the research conducted for this thesis, we have
identified three critical points for improvement:
• End-to-end data protection: Ensuring not only data transmission but also secure storage, data
processing, and data disposal. An enforced third-party validation practice for end-to-end protection
would add consumer safety and trust.
• Transparency obligations: Manufacturers and service providers should be more transparent about
how user data is handled regarding data sharing with third parties and make users aware that
their data, including video recordings, might be decrypted and viewed.
• Frequent reassessment of the RED directive: The EU should reassess the RED directive in
alignment with technological development to keep security in IoT devices up to date.</p>
        <p>Without such or similar reforms, the CE mark may ofer consumers little more than superficial
assurance, exposing them to privacy risks, despite technical compliance.</p>
      </sec>
      <sec id="sec-5-2">
        <title>4.2. Method discussion</title>
        <p>Due to limitations in time and resources, the sample size of IoT devices had to be restricted. Arguably, a
larger sample size could have yielded more variation in results, mainly since the majority of the IoT
devices purchased for this study were unfortunately based on the same IoT architecture. However, during
the device selection process, they were not identified as being produced by the same IoT developer; this
connection was only discovered during the penetration testing.</p>
        <p>The well-structured approach to data gathering also allowed for an iterative experimental process,
enabling us to revisit and redo experiments as necessary while learning more about weaknesses and
potential vulnerabilities in IoT devices. This provided an extensive and comprehensive dataset for the
analysis phase of the study, answered the research questions, and generated thought-provoking insights
into the world of cybersecurity for IoT devices, which were incorporated into the discussion and served
as the basis for future research ideas.</p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>5. Conclusions</title>
      <p>
        Our findings demonstrate that, despite CE-marking, significant security and privacy vulnerabilities
persist in IoT devices sold within and outside the EU. The rapidly increasing number of IoT devices,
coupled with the current state of RED Directive 2014/53/EU Article 3(
        <xref ref-type="bibr" rid="ref3">3</xref>
        )e, is insuficient to secure
European citizens’ data, as observed data often transits through multiple third-party domains globally.
The self-declaration process for the CE mark poses a direct threat to personal data security, evidenced
by plain text data transmission to manufacturers’ servers. These observations reinforce claims by Cote
et al. (2023) regarding unauthorized user data sales [24].
      </p>
      <p>While our sample size was smaller than ThreatLabz’s 2023 study [6] (which reported only 14.03%
TLS usage), we observed a positive security progression: 75% of tested European devices used TLSv1.2,
and 62.5% of Chinese devices used TLS1.0-1.2. Despite this improvement in encryption, the underlying
issue of data being transmitted to third parties and the vulnerabilities of the self-declaration process
remain critical concerns. Studies show that users do not really understand what they are agreeing to
and how their data is managed when accepting terms and policies[25].</p>
      <sec id="sec-6-1">
        <title>5.1. Practical implications</title>
        <p>
          This research highlights the unwitting privacy and security risks faced by European consumers using
Wi-Fi-connected devices from both domestic and foreign retailers. The identified flaws in RED Directive
2014/53/EU Article 3(
          <xref ref-type="bibr" rid="ref3">3</xref>
          )e and the lack of specific smart home device directives suggest an urgent
need for strengthened regulations regarding product sales and privacy requirements for devices sold
to European citizens. Our collected data can be used to raise awareness among policymakers and
consumers regarding these critical privacy issues.
        </p>
      </sec>
      <sec id="sec-6-2">
        <title>5.2. Scientific implications</title>
        <p>Our experimental results significantly impact the scientific community, particularly in IoT development,
system architecture, and user privacy implementation. The observed lack of privacy implementations
and the limitations of the self-declaring CE mark indicate a clear research opportunity. This opens
avenues for investigating new data authentication systems, such as a neutral third-party certification
service, to control product data transmission routing before market release in Europe.</p>
      </sec>
      <sec id="sec-6-3">
        <title>5.3. Future work</title>
        <p>Future research could productively expand the device sample pool and geographical scope to include
more countries, ofering a broader global perspective on consumer exposure and standard adherence.
Investigating user awareness and behavior regarding CE-marking and privacy risks would also be
valuable in understanding consumer decision-making. Additionally, exploring how edge-based AI or
federated learning could enhance local data privacy in smart devices ofers promising insights. Lastly,
researching the impact of user education and cybersecurity training on mitigating security gaps, without
extensive legislative reform, warrants further studies such as [26].</p>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>Declaration on Generative AI</title>
      <p>During the preparation of this work, the author(s) used Grammarly and ChatGPT in order to:
Grammar and spelling check. The author(s) reviewed and edited the content as needed and take(s) full
responsibility for the publication’s content.
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