[Jfreegman]

You missed my point again, and your tangent on randomness is unnecessary; I have no misconceptions of how randomness works, and it is precisely that understanding that has lead me to these decisions - a pure random password generator produces every word in the English language. That's not a good thing!

The point remains that if your password generator produces passwords such as "aaaaaaa" then it is a bad algorithm, end of discussion. It doesn't matter if the passwords it produces are completely random. That's not the goal and is completely irrelevant. The goal is to produce unique, unpredictable passwords that utilize randomness. We're not producing fixed-length keys. In the average case for web-based logins, uniqueness is far more important than entropy.

So, I'll say it once more. If you can demonstrate how passwords generated by the algorithm I wrote are predictable or otherwise insecure in a real-world setting as you claim, then do it. If you cannot, then any further responses are in vain.

[tialaramex]

> The point remains that if your password generator produces passwords such as "aaaaaaa" then it is a bad algorithm, end of discussion.

The correct algorithm does this, and you've managed to convince yourself that this is bad and it's time to invoke lots more complicated code. This is the end of the discussion in the sense that you've departed from reality so severely that you may be unable to recover.

Here's how zxc24's 'pass' does it:

  read -r -n $length pass < <(LC_ALL=C tr -dc "$characters" < /dev/urandom)

For those who can't read shell that's saying to run the random data from the OS kernel through a pipeline which removes everything except $characters and then consume $length bytes of the result as the new password.

This absolutely can give you "aaaaaaa" as a password if you've unaccountably chosen to use such short passwords - but no more easily than it might choose "fuckwit" or "X3_$mwK" or any other sequence of permitted symbols.

But enough about how to do this correctly, you're very focused on your bizarre way to pick "unique, unpredictable passwords that utilize randomness", so let's look at that again:

The tight inner loop picks characters randomly using code from Sodium. Unfortunately it discards characters from the candidate list once it has picked them, and then it has a further rule which may ignore this (already discarded) character and go round again.

For the short case (size = 4) this means it can produce only about 5.2 million different passwords, whereas a better (simpler) solution gives 78 million different passwords, you've made it more than a decimal order of magnitude worse.