I need to copy some data from a secure server to my laptop to work on it with a program (this description is very vague, I know). The data have six digit employee numbers and we are strictly prohibited from downloading data with these.
I was wondering if there is a really simple hash function I could put in a spreadsheet to convert these employee numbers into a one way hash so I can download these? All I care about is being able to tell which data came from the same employee number. I am not terribly concerned about a few collisions either, the set is small enough I could look for those.
I was thinking some simple xor with an added salt or squaring and taking some digits but everything seems like it would be too guessable especially if there is a series of sequential employee numbers in a row.
For example, hash
somerandomlookingstring, but I need to be sure the next result is
is not terribly similar, so not like:
I feel like this is something hardcore crypto people may know off-hand, some mini ancestor of MD5, some evolution of ROT13, but light enough for thousands of spreadsheet cells.
light enough for thousands of spreadsheet cells- have you actually tested just using SHA256/SHA512? It is entirely possible (if not even probable) that the perceived performance problem is not actually a problem. $\endgroup$