Improving Mobile Security with Visual Trust Indicators for Smishing Detection

Smishing (SMS phishing) is a growing cyber threat that exploits user trust in text messages. Many users struggle to distinguish between legitimate and fraudulent messages, increasing their risk. To address this problem, we researched and developed options for visual trust indicators that can be displayed to guide mobile phone users in judging messages. We evaluated the indicator options with 30 participants. Participants preferred intuitive, color-coded icons, especially when familiar and contextually clear. Non-verbal icons enabled low-effort recognition, while tooltips were valuable when they provided clear, actionable options like one-click reporting. Profile with shield icons and triangle road signs were most effective. Our findings highlight how visual indicators enhance user security and confidence, while also supporting more informed decision-making. We recommend accessible and customizable designs that align with user expectations. These insights have broader relevance for improving mobile messaging and securing IoT environments where compromised phones can trigger downstream risks.