This script generates random passwords. Each one is made of up four dictionary words, separated by spaces. Passwords of this format are easy to type and remember, and are surprisingly strong.
To use the script, clone this repo, then run this command from within the source directory:
ruby generate.rb
Here's an example of the output (don't use these passwords, of course):
wont daughter cells georgetown
resource antibodies prince flute
tunisia hide pins terror
album feature enemy isaac
ginger graphs critic minnesota
sailing chef fires superb
stuart parents conditions historic
department enterprises title netscape
avalon collapse copyright climb
fare historic struck streaming
It prints out several possibilities so that you can choose the one that seems most memorable to you. If you don't like any of them, run it again.
The script draws from a vocabulary of around 10,000 common words. The words have been mostly screened for offensive entries, so it should be safe to demonstrate its use at work or in public.
Companies' password databases routinely get compromised and published, exposing your username and password for those accounts. Strong, unique passwords will protect your accounts from most of these attacks.
A good personal password security policy can be summarized as follows:
- Use a password manager such as 1Password to generate and store strong, unique passwords for everything.
- Never reuse any password. Generate a new one for each site, account, or purpose.
- Use this script to generate the one or two unique passwords that you must remember, e.g. your laptop's login password, and the master password for your password manager.
- Change your most important passwords periodically (say once per year). Using the techniques above, this should not be too onerous.
- Don't use any computer that you suspect could be compromised. If you suspect that your own computer has been compromised, shut it down and consult a security expert to safely recover your data and start over.
The XKCD cartoon above illustrates the problem with traditional made-up passwords:
Through 20 years of effort, we've successfully trained everyone to use passwords that are hard for humans to remember, but easy for computers to guess.
This script implements the four-random-word technique that he described.
The XKCD technique, as implemented here, is about as strong as an 8-character random password:
irb> Math.log(95 ** 8).round(2) # 8 random characters, including punctuation
=> 36.43
irb> Math.log(10_000 ** 4).round(2) # 4 random common words
=> 36.84
While the XKCD technique may not be strong enough to fully protect passwords at sites that use weak hashing algorithms, both 1Password and the Mac login keychain use very strong algorithms, so this should be plenty strong for those two purposes. Use your password manager to generate long, random passwords for all other scenarios, as described in the recommendations above.
I arrived at the ~10,000 words contained in the script through the following process:
- Download the 1/3 million most common words from Peter Norvig's Natural Language Corpus Data.
- Trim that list down to the top 12,000.
- Remove the number counts from each row using sed/search/replace.
- Sort the list alphabetically for easier reading.
- Manually scan through the list and delete entries that may be offensive or awkward in a work setting or public speaking environment.
Obviously the last step is a bit error prone. I may have missed a few offensive/awkward words.
The original XKCD comic that describes the problem with made-up passwords:
An article that describes how passwords are typically harvested from compromised websites:
http://arstechnica.com/security/2012/08/passwords-under-assault/
Advances in commodity hardware are making it even easier for attackers to break weak passwords:
Recent attacks at common websites that put all their users' passwords at risk: