I've seen the following regular expression around the web.
It validates only if the string:
* contain at least (1) upper case letter * contain at least (1) lower case letter * contain at least (1) number or special character * contain at least (8) characters in length
I'd like to know how to convert this regular expression so that it checks the string to
* contain at least (2) upper case letter * contain at least (2) lower case letter * contain at least (2) digits * contain at least (2) special character * contain at least (8) characters in length
Well, if it contains at least 2 upper,lower,digits and special characters then I wouldn't need the 8 characters length.
Special characters include:
The best way to adapt that regex is to chuck it out and write some code instead. The required regex would be so long and complicated, you wouldn't be able to read it two hours after you wrote it. The equivalent PHP code will be tedious, but at least you'll be able understand what you wrote.
This isn't meant as a slam on you, by the way. Regexes are just barely suitable for password-strength validation in most cases, but your requirements are more complicated than usual, and it's just not worth it. Also, that regex you posted is crap. Never trust regexes you find floating around the web. Or any code, for that matter. Or, heck, anything. :-/