Add support for Diceware wordlists in numbered and/or PGP-signed formats

[snipfoo]

Rationale

This allows one to directly use Diceware-compatible wordlists without having to convert the file to the plain wordlist format.

The accepted formats are described in the Diceware documentation: https://diceware.readthedocs.io/en/stable/wordlists.html.

Testing strategy

Tested with several wordlists from https://github.com/ulif/diceware/tree/master/diceware/wordlists. In particular, tested with a numbered wordlist (wordlist_en_eff.txt), a PGP-signed wordlist (wordlist_en_securedrop.asc) and a PGP-signed numbered wordlist (wordlist_en_orig.asc).

Type of change

• ✅ New feature (change that adds functionality)

[droidmonkey]

What is the point of using a signed wordlist if you don't check the signature? The signed lists are terrible as well since they have "words" that are 1 to 4 letters in length.

[snipfoo]

Hi,

Thanks for the feedback!

There are many wordlists outside of those distributed with Diceware, especially for other languages (e.g., diceware-wordlists-fr). The idea is that Diceware set a kind of de facto standard format for these wordlists (i.e., plain, PGP-signed and/or numbered), and that most of the wordlists that exist use this format. The idea here is to have the possibility to use these wordlists with KeePassXC without having to edit them to remove the PGP signature or the numbers (which can be quite a hassle and error-prone for users unfamiliar/unconfortable with editing large text files).

Verifying the PGP signature of a signed wordlist would be great, for sure, but, as is, KeePassXC requires the user to remove the signature altogether if they want to use this wordlist to generate a passphrase. At least, allowing KeePassXC to read signed wordlists allows the user to use the file as a drop-in replacement for eff_large.wordlist without having to remove the signature, and they can always manually verify the signature themself using GnuPG.

Actually, this is on par with Diceware's behavior, which does not verify the PGP signature either (see here):

Signed wordlists can be verified to detect changes, although this is not automatically done by diceware.

Therefore, I see this as simply increasing KeePassXC's compatibility with existing wordlists, without changing its normal behavior.

But if you think that this would help clarifying the situation, I can always write a caveat in the keepassxc-cli manpage stating that the PGP signature of the wordlist will not be verified.

Cheers!
SnipFoo

[droidmonkey]

Yes that is an important caveat similar to what diceware themselves wrote. Otherwise I don't have any grief with expanding the options pool.

[snipfoo]

Great, thanks for the quick reply!

d2cdef8 is a first try at documenting this in the keepassxc-cli manpage.

Cheers!
SnipFoo