A Privacy-Aware Hierarchical Membership Information System with UUID-Based QR Verification of Digital Membership Cards for a Faith-Based Youth Organization in Indonesia

Membership is the core asset of many faith-based youth organizations, yet in emerging economies it is often recorded on paper or in scattered spreadsheets, and printed membership cards cannot be verified or revoked once issued. Recent studies report that nonprofit digital transformation is under-theorized and that Indonesian evidence is scarce, while digital credential research favours blockchain or self-sovereign identity designs too costly for small volunteer organizations. This study designs and evaluates a web-based membership information system for the Regional Board of Pemuda Muhammadiyah in Sukabumi Regency, Indonesia. The system encodes the organization's region, branch and twig hierarchy and its bylaw age limit directly in the data model, derives membership status at read time, and issues digital membership cards whose QR code carries only an opaque version 4 UUID that is resolved against live server records, so that revocation requires no reissuance. A privacy-by-design audit aligned with Indonesian Law No. 27 of 2022 on Personal Data Protection is proposed together with a data exposure ratio for the public verification endpoint. Artefact analysis shows that the current verification page discloses 9 of 23 stored personal attributes, including date and place of birth, and identifies ten remediable privacy, access-control, functional and usability defects. A usability survey of 86 student participants gave a mean System Usability Scale score of 61.8 (95% CI 57.8 to 65.8) after excluding 25 straight-lined responses, below the benchmark of 68; open answers traced the main problems to entered data lost after a failed submission and a dashboard not adapted to small screens. All 150 automated verification trials returned the correct status, but pages of pending and rejected applicants still disclosed names and membership numbers. Median verification latency over 4G was 0.26 s. The study contributes a low-cost, regulation-aware reference design for membership digitalization in hierarchical nonprofit organizations.