Password Managers

> I never really understood this. Ed25519 keys use SHA-512 and are considered secure. They're still just long secrets, aren't they?

No. I find it easiest to keep this straight in my head with a line from the U2 song "The Fly", "a secret is something you tell one other person". You're thinking of Ed25519 private keys, you mustn't tell those to anybody and they're minted as a pair with a public key you can tell to everybody.

> What's to prevent me from using a similarly long, randomly generated secret as my password

That's a Shared Secret. You tell the password to the remote web site. They have a copy of it, their permanent copy of it is likely hashed, but you send them a new, unhashed version of that same password to the site every single time you log in.

This makes all the difference in the world. Let's see that in action:

Suppose that Edward, who is Evil, has complete insight into everything stored by and every program running at Facebook for an hour. If someone logs into Facebook using a password, obviously Edward learns the password, it was sent to Facebook so they could check it was correct. So Edward can log in as any Facebook user who logged in while Edward's magical insight lasted? Right?

Nope. Facebook has WebAuthn. For WebAuthn users logging in involves public key cryptography. Facebook has a public key for those users but no private key. Edward can see that the users were properly authenticated, but he doesn't get a persistent credential because the persistent credential never left the user's grasp. He cannot log in as those users, only they can do that.

If you use a password manager that's two factor, then you are still at two factors. e.g. vault-based or hardware key based

I do not use a browser-based password generator, because of the Javascript insecurity issues (edit: And because I’ve been using a system like this far longer than online password managers have existed). I use a shell script, with a small C program to handle the core cryptography, to generate secure passwords.

I run the password generator in a terminal window, then copy and paste the password in to the site I am trying to log in to.

It’s a fairly complicated shell script, since it also has to deal with nonsense like stupid arbitrary password rules (e.g. Southwest considers an underscore to be a letter, and insists at least one non-letter non-number punctuation is in a password; some places require a password to be 8 characters or shorter; etc.) and also provides login information so I can also remember my username.

As recently as 5 or 6 years ago, there were issues with websites which wouldn’t let you copy and paste a password in to their password field; Firefox has always had a “ignore any Javascript which stops pasting” special rule in about:config I had to use. I haven’t seen one of those in a while; developers finally got a clue and realized that password managers exist.

One weakness this setup has is that anyone with the “master key” can get all of the password generated by the password generator. My workaround is to use a separate master key in a virtual machine for critical passwords, such as online banking ones.

Shameless plug time:

https://github.com/samboy/PassGen/

Good point. This is also the same for KeePassXC where the browser extension works by communicating with the main app process. The extension itself doesn't store the passwords.

And KeePassXC is open source and does not require cloud storage. So you can build from source and do not need to rely on any claims from the vendor on how the data is securely stored.

Or

openssl rand -base64 12

If a couple attempts at that doesn't generate a password that satisfies complexity requirements, add, remove, or change a character or two before pasting. Change 12 to a larger or smaller number to change the length of the generated pw.