when I first learned about checksums (it was in high school, in the context of tarballs for linux packages and for entire distros), my attention *immediately* snapped to their potential use as direct reference to referent - *in the absence* of the original. the idea as it first occurred to me: "wait with a sufficiently granular checksum, and knowing some clarifying fact about the original (like filesize), given sufficient access to information we should be able to recall the original referent".
in an observer-first model of universe ("reality" as an instantiation of "relationality"), a computational checksum becomes a pointer to an exact moment in time - to the moment when a defined body of data (the input) was met by someone you knew who you still recognize today (the digest function)
... this might be why a body wants to find its birth parents, actually