Shared Responsibility in Practice: Evaluating the Security–Usability Trade-Off and User Accountability in WhatsApp’s Ecosystem

This study critically evaluates WhatsApp’s security ecosystem through a shared responsibility framework, examining the interaction between platform safeguards, usability, and user accountability. A mixed-methods approach was employed, integrating four open-access cybersecurity datasets with primary data from a structured questionnaire completed by 835 respondents and semi-structured interviews with five members of an alumni WhatsApp group affected by an account breach. Analytical techniques included sentiment–feature mapping using logistic regression, risk distribution profiling with Relative Risk Ratios, exploratory factor analysis with Cronbach’s Alpha, multivariate time-series correlation with Granger causality, and thematic analysis of interview transcripts. Results indicate that two-step verification recorded the strongest positive sentiment and highest odds ratio (OR = 2.34), yet adoption remained low, with fewer than 40 percent of users enabling the feature. Investment fraud accounted for 61 percent of high-loss scam cases, while questionnaire responses revealed persistent engagement in risky behaviours such as joining unverified groups. Qualitative findings further demonstrate that trust dynamics, misunderstanding of security prompts, and limited practical awareness significantly contributed to the observed account breach. Behavioural accountability constructs explained 80 percent of variance in security outcomes; however, only 24 percent of users consistently exhibited high accountability. Platform-level interventions such as key transparency were associated with reductions in banned accounts (r = −0.62, p = 0.04), while spikes in abuse incidents triggered reactive increases in two-step verification adoption. These findings underscore the limitations of encryption-centric security models and highlight the need for improved usability, targeted awareness strategies, and strengthened user accountability. The study provides actionable insights for platform designers, policymakers, and users seeking to enhance digital resilience in encrypted communication environments.