@bot @alex @chud @realcaseyrollins a hash is a unique or semi-unique small fingerprint of a file that you can use to identify if you've seen a file before without keeping the actual file.

so you see a file you don't want to keep because it's evil. you hash it and save the hash. then later without ever looking at a file you can hash it and check if it matches. if the fingerprint matches it's probably the same file. this is done because storing files for comparison takes a ton of space (a hash might just be like 32 letters or so) and files might be bad like csam and you don't want people holding them to identify them.