PHP validation check for numeric and alphabetic sequence [duplicate] - php

Question

This question already has an answer here:
Reference - What does this regex mean?
(1 answer)
Closed 5 years ago.
one of the rules in our password creation is, it shouldn't contain a sequence of number or alphabets.
ex.12345, pwd45678, pwd_abcdef, pwd_abc123
all of these are not allowed.
Any suggestion how to check for sequence?
By sequence meaning it shouldn't be order like for numbers 1-10 or letters in the alphabet. So the password shouldn't contain alphabet sequence or order and numbers in 1-10 order. So password containing ABC or DEF or HIJK is not allowed and passwords containing number orders like 1234 or 4567 are not allowed but passwords containing ABNOE or 19334 is ok.
TIA

Answer 1

A specific rule for no 2 adjacent digits or letters:
if (preg_match("#(\d{2,}|[[:alpha:]]{2,})#u", $input)) {
return false;
}
You can try it out here.
However, there are packages available specifically for password strength checking. They will have configurable rules or tests.

Answer 2

you can use the code below,I used the "asci code" to resolve the problem, it is already tested for your examples :
<?php
$passwords = [
'12345',
'pwd45678',
'pwd_abcdef',
'pwd_abc123',
];
var_dump(check_password_sequence($passwords[3], 4));
function check_password_sequence($password, $max) {
$j = 0;
$lenght = strlen($password);
for($i = 0; $i < $lenght; $i++) {
if(isset($password[$i+1]) && ord($password[$i]) + 1 === ord($password[$i+1])) {
$j++;
} else {
$j = 0;
}
if($j === $max) {
return true;
}
}
return false;
}