Would concatenating (i.e. joining together into one string of text) a secure (i.e. Diceware) password and other, much less random, passwords be a good idea? This new password would be used as master password for my password manager, and, since it would replace all my passwords, why not concatenate all of them into one and append a secure one? Obviously, each service would use a new password generated by the password manager.

Intuitively, it would be more secure since the password is longer. The disadvantage, of course, would be that I'd have to type more.

Are there any downsides I'm not aware of?

  • please edit your question to clarify - are you proposing to use one password for all services, or, are you proposing to store a randomised prefix in the password manager, while retaining a secret diceware phrase in your head that you then add manually at time of login? (ie. in case the contents of the pwd database gets leaked)
    – brynk
    Nov 15, 2020 at 2:05
  • Thank you. Is the question clear enough now? Nov 16, 2020 at 3:08
  • It seems alright by me. Sure, a lot to type, but that's okay. Alternatively, you could also get a YubiKey that automatically types an extremely long passphrase for you.
    – user163495
    Nov 16, 2020 at 10:36

1 Answer 1


This new password would be used as master password for my password manager

I am against this. The thing about using passwords that are similar or have a part to play in other password would be considered a bad idea.

Which in your case would be, having phrases from other passwords to make up the master password. The moment any on your passwords are compromised, it places your master password at a higher risk than it should be. Password Cracking techniques have exponentially gotten better, faster & smarter.

Depending on the type of attack, any newly added information would contribute in the time taken to crack your passwords, let's not contribute to that.

  • But part of the password would be a diceware password Nov 19, 2020 at 20:20

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