During an internship for a small company, my boss created an account for me, so I generated a password and I used it. The next day, my boss told me to write down the password of my account on a piece of paper, put it in a letter and to sign the envelope. Then he took the letter and told me that if he needs to access my account and I am unreachable, he is authorized to open the envelope and read the password to use it.
He also told me that this is a common practice in all companies. Now I don't know if every company does this (I don't think so) but, to me, it's not legal.
Let's say that my boss is a bad person (he's not) and he wants to frame me for something that he did. He only has to open the letter and read my password (let's say that I'm unreachable) and do his nefarious activity with my account.
Now let's say that I can't prove my innocence. How I can prevent all of this? I thought of writing down a wrong password, but if he really needs my account and I'm unreachable, I'll put him in a bad situation.
So, is there a way to protect myself (without refusing to write down the password)?