Generate good passwords for use on mobile devices/smartphones

gen-password.php

<?php

/*
Generate good passwords for mobile use
Created by David Spector, Springtime Software 2022
Public Domain
ver=7/20/22 released

Tested only on Windows 10: uses PHP function random_int

For run length 0, passwords are 0 characters long, and there are 1 unique passwords possible
For run length 1, passwords are 3 characters long, and there are 4608 unique passwords possible
For run length 2, passwords are 6 characters long, and there are 97844723712 unique passwords possible
For run length 3, passwords are 9 characters long, and there are 9.5735899582776E+21 unique passwords possible
For run length 4, passwords are 12 characters long, and there are 4.3164300183536E+36 unique passwords possible
For run length 5, passwords are 15 characters long, and there are 8.9678235849214E+54 unique passwords possible
*/

define("RUN_LEN",3); // 2: length of pwd=6, 3: len=9, 4: len=12

$sets=['ABCDEGHJKLMNOPQRSTUVWXYZ',
'abcdeghijkmnopqrstuvwxyz',
'23456789'];
define("SET_LEN",3);

$perms=[[0,1,2],[0,2,1],[1,0,2],[1,2,0],[2,0,1],[2,1,0]];
define("PERMS_LEN",6);

define("SETS",$sets);
define("PERMS",$perms);

// ver=7/20/22
// Length of result pwd is SET_LEN*RUN_LEN
function GenPassword()
	{
	$pwd='';

	// Select a random permutation of the char type sets
	$perm=PERMS[random_int(0,PERMS_LEN-1)];

	for ($i=0; $i<SET_LEN; $i++)
		{
		$setNr=$perm[$i];
		$set=SETS[$setNr];
		$setSize=strlen($set);
		for ($j=0; $j<RUN_LEN; $j++)
			$pwd.=$set[random_int(0,$setSize-1)];
		}
	} // GenPassword

// Tests
for ($i=0; $i<100; $i++)
	{
	//$pwd=GenPassword();
	}
?>