Future superintelligent AI will be able to reconstruct a model of the personality of a person who lived in the past based on informational traces. This could be regarded as some form of immortality if this AI also solves the problem of personal identity in a copy-friendly way. A person who is currently alive could invest now in passive self-recording and active self-description to facilitate such reconstruction. In this article, we analyze informational-theoretical relationships between the human mind, its traces, and its future model; based on this analysis, we suggest the instruments to most cost-effectively collect quality data about a person for future resurrection. These guidelines form a “digital immortality protocol”. Digital immortality is plan C for achieving immortality, after plan A, life extension, and plan B, cryonics.