You can always create a new set of commits (git will let you change the dates to what ever you want) and force push to master. Will look completely legit, unles

You can always create a new set of commits (git will let you change the dates to what ever you want) and force push to master. Will look completely legit, unless somebody else has a prior checkout, or a hash. That is how you make it work: at the end of each workday, email somebody neutral the hash of head.