“…For example, in our research we found existing solutions based on trusted computing modules [see, e.g., 1, 52, 67], cryptographically secured protocols such as forwardsecure authentication [see, e.g., 3,41,55], or distributed ledger technology, i.e. blockchain [see, e.g., 33,77,97]. Recent challenges seem to include heterogeneity of hardware [52] and GDPR compliance, especially considering the right to erasure [96].…”