PHP regular expression for strong password validation [duplicate]

by

I have to agree with Alan. If the existing regex is so complicated, why try and do it in just one regex?

Just break it down into approachable simple steps. You have already done that.

Now write 4 regex to validate your parts, add basic logic to the 4 regex and measure the length of the string. Done.

Which would you rather debug, this:

(?=^(?:[^A-Z]*[A-Z]){2})(?=^(?:[^a-z]*[a-z]){2})(?=^(?:\D*\d){2})(?=^(?:\w*\W){2})^[A-Za-z\d\W]{8,}$ (which does not work btw…)

or this:

function valid_pass($candidate) {
   $r1='/[A-Z]/';  //Uppercase
   $r2='/[a-z]/';  //lowercase
   $r3='/[!@#$%^&*()\-_=+{};:,<.>]/';  // whatever you mean by 'special char'
   $r4='/[0-9]/';  //numbers

   if(preg_match_all($r1,$candidate, $o)<2) return FALSE;

   if(preg_match_all($r2,$candidate, $o)<2) return FALSE;

   if(preg_match_all($r3,$candidate, $o)<2) return FALSE;

   if(preg_match_all($r4,$candidate, $o)<2) return FALSE;

   if(strlen($candidate)<8) return FALSE;

   return TRUE;
}

Why folks feel they have to write a regex that no one can understand just so they can do it in one go is beyond me…

Ok ok — if you really want a single regex, learn about lookaheads to validate your rules.

This monster does what you asked in one go:

^                                        # start of line
(?=(?:.*[A-Z]){2,})                      # 2 upper case letters
(?=(?:.*[a-z]){2,})                      # 2 lower case letters
(?=(?:.*\d){2,})                         # 2 digits
(?=(?:.*[!@#$%^&*()\-_=+{};:,<.>]){2,})  # 2 special characters
(.{8,})                                  # length 8 or more
$                                        # EOL

Demo

More Related Contents:

  1. Regex for password PHP [duplicate]
  2. Regex For a Simple Validation [closed]
  3. PHP validation/regex for URL
  4. How to validate an Email in PHP?
  5. How to “Validate” Human Names in CakePHP?
  6. Regex to detect invalid UTF-8 string
  7. Validating Crontab Entries with PHP
  8. Validating US phone number with php/regex
  9. PHP regex for validating a URL
  10. How to validate that a string only contain lowercase letters?
  11. Validate date format in php
  12. regular expression [closed]
  13. Regex to validate range of numbers from 50 to 1000 with step of 50 [closed]
  14. I want to make my password to contain lowercase, uppercase, 8 characters and a character
  15. How do I find all YouTube video ids in a string using a regex?
  16. How to mimic Stack Overflow Auto-Link Behavior
  17. Remove control characters from PHP string
  18. How do I make this preg_match case insensitive?
  19. Matching a space in regex
  20. Why is password_verify returning false?
  21. Strip all HTML tags, except allowed
  22. PHP Regex find text between custom added HTML Tags
  23. Function eregi() is deprecated [duplicate]
  24. regex matching links without tag
  25. Regex & PHP – isolate src attribute from img tag
  26. Regex for checking if a string has mismatched parentheses?
  27. How to validate a domain name using Regex & PHP?
  28. Checking if a string contains an integer
  29. How to remove all numbers from string?
  30. Regular expression preg_quote symbols are not detected

Leave a Comment