[rwz]

I actually tried doing this at some point before 1Password. One obvious problem with this approach is when you’re forced to change your password. You can’t change salt, or hash function for obvious reasons, so you have to change site name.

At some point guessing the original input becomes tedious, when you’re trying to remember if your github password has name “github.com2” or “github.com-3”

Edit:

Completely forgot about another huge usability issue. Some sites enforce weird rules for what symbols are allowed, or what length your password should be. Every time your function generates something that doesn’t pass validation, you’re forced to pretty much revert to your pre-password-management behavior. Obviously you won’t remember that a year later when you suddenly realize that generated password doesn’t work.