Comments on: Password Strength Validation with Regular Expressions

By: *blog » Blog Archive » Visual password strength checker for jQuery

*blog » Blog Archive » Visual password strength checker for jQuery — Mon, 25 Jan 2010 19:30:40 +0000

[...] on the work of http://www.zorched.net/2009/05/08/password-strength-validation-with-regular-expressions/ and [...]

By: vaibhav

vaibhav — Sat, 07 Nov 2009 18:14:48 +0000

Pretty nice explanation. Thanks a lot.
I have implemented a it on one of my website.
Take a look at the script I have written. http://www.techpint.com/programming/regular-expression-check-password-strength

By: Tony Norton

Tony Norton — Tue, 13 Oct 2009 18:59:56 +0000

I modified Geoff’s regex for my situation for:
8 characters only

Password must contain 3 out of the 4 of these:
• lowercase letter
• uppercase letter
• number
• special character ! @ $ % ^ & * ( ) + ?

^(((?=.*[a-z])(?=.*[A-Z])(?=.*[\d]))|((?=.*[a-z])(?=.*[A-Z])(?=.*[\W]))|((?=.*[a-z])(?=.*[\d])(?=.*[\W]))|((?=.*[A-Z])(?=.*[\d])(?=.*[\W]))).{8,8}$

By: Geoff Lane

Geoff Lane — Mon, 31 Aug 2009 18:03:04 +0000

Dave and Lee,
The assertions don’t return matches, just true/false, so they can’t be counted using repetition operations like {3,}. I think your best bet in those cases is to separate them out into multiple regex expressions and just count your matches.

As Dave suggests, you can also use alternation (or operator) to do this, but you then have to create all the permutations of the assertions:

^.*(?=.{12,})(((?=.*[a-z])(?=.*[A-Z])(?=.*[\d]))|((?=.*[a-z])(?=.*[\d])(?=.*[\W]))|((?=.*[A-Z])(?=.*[\d])(?=.*[\W]))|((?=.*[a-z)(?=.*[A-Z])(?=.*[\d]))).*$

It gets pretty gnarly pretty quickly…

By: Lee

Lee — Mon, 31 Aug 2009 16:58:42 +0000

I have the same issue as Dave. How can I handle this in RegEx?

Password must be at least 12 characters long.

AND

Password must contain 3 out of the 4 of these:
• lowercase letter
• uppercase letter
• number
• special character ! @ $ % ^ & * ( ) + ?

By: Dave

Dave — Tue, 25 Aug 2009 01:58:03 +0000

Hi,
Thanks for the explanation.

How do you go about requiring at least 3 of 4 assertions? We require 3 of 4 within the sets upper, lower, numeric, and special. I want to use {3,} somewhere I think. One idea I had would be to use alternation to list out all of the possibilities. Is that possible with assertions?

Thanks.

By: Beau Beauchamp

Beau Beauchamp — Sun, 23 Aug 2009 10:46:27 +0000

Geoff, you are a RegEx Jedi! Thank you so much for these! Exactly what I was looking for! THANK YOU! :D