DNA 9ngerprinting

awk '{print $2}' /etc/ssh/ssh_host_ed25519_key.pub | base64 -d | sha256sum -b | sed 's/ .*$//' | xxd -r -p | base64 | sed 's/.//44g' | awk '{print "SHA256:"$1}'

even on text data the assumption thatone can always find reasonable sentences is questionable

If the ID can’t be extracted (because the PDF doesn’t contain a trailer, the trailer doesn’t contain a valid ID array, etc) then use an MD5 digest of the first 1024 bytes of the file instead

The ID entry is an array of two byte strings. The first byte string in the array is a “permanent identifier” that’s “based on the contents of the file at the time it was originally created” and “shall not change when the file is incrementally updated”. This is the identifier that we’re interested in. The second byte string is a secondary identifier that should also be based on the contents of the file, and should initially have the same value as the first identifier, but that should be re-computed based on the new file contents each time the file is updated. It enables you to identify a different version of the same file. Hypothesis doesn’t use this second identifier.

The prevailing hypothesis has been that volcanoes like these two in Hawaii are chemical fingerprints of the Earth’s composition at the deep mantle, just at the border of its core.