Simply run ./generate.sh to generate a passphrase based on the XKCD method:
By default this uses the 2,048 most popular words in the English language. To use the N (between 4 and 10,000) most popular words instead simply run ./generate.sh N. For example, ./generate.sh 10000 prints the strongest password this can generate.
The word list is based on another repository. Many thanks to Josh Kaufman, Peter Norvig and Google for contributing this. If anyone knows of a list of most popular contemporary English words which is definitely Creative Commons licensed or in the public domain, please let me know.
Using your own word list is easy - simply replace words.txt with your own file.
Adapting this to other languages would be easy. If you can provide a list of at least the 2,048 most popular words in a language (sorted by decreasing popularity) I can adapt this program for your language. Please file an issue and include a link to the word list.
Notes:
- The original comic quoted “~44 bits of entropy” for a four word passphrase like “correct horse battery staple”, making it simple to assume that the dictionary contained 2,048 words (2^(44/4)). The dictionary used is unknown, but even though the first three words are all in the word list, “staple” is actually word number 333,333 in Peter Norvig’s list.
- The security of this approach has been discussed elsewhere. User beware.
The code is licensed under the GNU Affero GPL v3+.