I made one in Ruby a few weeks ago. Please don't do what ghshephard does below and blindly import random. It's actually quite important that you use a secure ra

I made one in Ruby a few weeks ago. Please don't do what ghshephard does below and blindly import random. It's actually quite important that you use a secure random generator, or your entropy will be drastically reduced. My solution is here, don't use it unless smart people have confirmed that it works: https://github.com/d-snp/wachtwoord/blob/master/wachtwoord.rb https://github.com/d-snp/wachtwoord/blob/master/wachtwoord.r... Also smart people: please let me know if I've done anything stupid here, I actually use passwords generated by this tool. For people who don't enjoy reading Ruby: My tool reads in a dictionary file, drops any too small words because they don't have enough absolute entropy and too long words because they're harder to remember (for Dutch anyway, your mileage might vary in your own language). You can vary the amount of words you want to have in your passphrase, and the tool will print how much entropy the password has if the attacker is aware that you're using this scheme and this dictionary file, but not aware of the random values spitted out by the random generator to pick the words. It will also spit out a cheesy ballpark estimate as to how long it might take an attacker to crack this password with reasonable effort, you can tweak what reasonable effort means for your context. What currently is a reasonable attack depends heavily on the hashing scheme you employ.