Regular Expression for a password with at least 8 characters and at least 1 non-alphanumeric character(s)

php regex passwords non-alphanumeric
Johnathan Au picture Johnathan Au · May 23, 2012 · Viewed 15.4k times · Source

I am trying to make a check in PHP if a user changes their password their new password must be 8 or more characters and with at least 1 non-alphanumeric password. How should I check this and what would the regex be?

Checking the length is the easy part strlen >= 8. My problem is regular expressions. I really have no clue about regular expressions even after years of studying computer science.

Thanks

Answer

nickb picture nickb · May 23, 2012

Try something like this to check if they used non-alphanumeric characters:

if( !preg_match( '/[^A-Za-z0-9]+/', $password) || strlen( $password) < 8)
{
    echo "Invalid password!";
}

The if statement will evaluate to true if the $password does not contain at least one of the characters not in the list (alphanumeric characters).

Related questions

Create preg_match for password validation allowing (!@#$%)

I would like to create a preg_match function to validate my passowrds, but I'm not sure how to write it to allow the following special characters to be used: !@#$%. if(!preg_match(?????)$/', $password)) Here are my password rules …

Read More
Remove all special characters from a string

I am facing an issue with URLs, I want to be able to convert titles that could contain anything and have them stripped of all special characters so they only have letters and numbers and of course I would like …

Read More
Matching a space in regex

I need to match a space character in a PHP regular expression. Anyone got any ideas? I mean like "gavin schulz", the space in between the two words. I am using a regular expression to make sure that I only …

Read More