Create strong passphrases with EFF's new random number generators! This page includes information about passwords, different wordlists, and EFF's suggested method for passphrase generation. Use the directions below with any set of dice.And now, a message from internationally renowned security...
This is really good for encrypted content such as a hard drive, password vault or gpg key
So TL;DR, the XKCD method, but with six words instead of four and using a larger wordlist?