The Turkish password word may be the same used for signature? I suspect so, because in Greek we have the Greek word for signature but also a Turkish loan word τζίφρα (djifra).

imza is signature while şifre is password. I imagine the conflation occurred because signatures are used like passwords for authentication...

Hmm i don’t think that one is related in Turkish — i only know of “imza” as signature, but there could also be other variants.