[Whonix-devel] Password length and Quantum Computing Implications

Fri Aug 10 22:26:00 CEST 2018

Hi JP. Whonix dev here. We are currently discussing the best advice for
generating strong passphrases for our users and so I wanted your advice
on a few questions.

According to The Intercept [0] using something like diceware is
recommended and a 10 word passphrase has 128 bits of more than enough to
stop the strongest adversaires for the forseeable future.

The IAD/NIST [1] recommends using 256 bit encryption for AES. Does this
translate into a need for 256 bit passphrases?

I may be misunderstanding but cipher keylength =/= password entropy?

Do quantum computers have implications for passphrase (not master key)
bruteforcing?

Now if it turns out I’m wrong the question becomes: how can a 10 word
passphrase be easily enhanced to get as high entropy as possible without
having to double its size?

There is an option for diceware to sprinkle random characters in its
output but I don’t know how much entropy bits it adds. Do you know?

I CC'd our mailing list so ou reply can benefit our users. Thanks in
advance.

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[0]
https://theintercept.com/2015/03/26/passphrases-can-memorize-attackers-cant-guess/
[1] https://www.keylength.com/en/compare/