Php > Miscellaneous

Password Generation Function

Password Generation Function

<?php 

    # Seed the random generator - consider doing this in a config file once for the entire site 
    mt_srand((double)microtime()*1000000); 

    /* PUBLIC */ 
    function password_generate($nice = 1, $length=0, $allowchars = "") { 
        # Find random password length 
        if (!$length) $length = mt_rand(5, 9); 

        # pronouncable password 
        if ($nice == 1) return password_generate_pronouncable($length); 
        # lowercase only, fix similar 
        else if ($nice == 2) return password_generate_advanced($length, 0, 1, 0, 0, 1, $allowchars); 
        # lowercase and numbers only, fix similar 
        else if ($nice == 3) return password_generate_advanced($length, 0, 1, 1, 0, 1, $allowchars); 
        # both lower and uppercase chars and numbers , fix similar 
        else if ($nice == 4) return password_generate_advanced($length, 1, 1, 1, 0, 1, $allowchars); 
        # all types of letters, including special chars, fix similar 
        else if ($nice == 5) return password_generate_advanced($length, 1, 1, 1, 1, 1, $allowchars); 
        # oh my :) the real deal - get it all and dont fix similars 
        else if ($nice == 6) return password_generate_advanced($length, 1, 1, 1, 1, 0, $allowchars); 

        # $nice contained illegal value, go for the easy 3 
        else return password_generate_advanced($length, 1, 1, 1, 0, 1); 
    } 


    /* PRIVATE */ 
    function password_generate_advanced($length = 8, $allow_uppercase = 1, $allow_lowercase = 1, $allow_numbers = 1, $allow_special = 1, $fix_similar = 0, $valid_charset = "") { 
        # Create a list of usable chars based upon the parameters 
        if (!$valid_charset) { 
            if ($allow_uppercase) $valid_charset .= 'ABCDEFGHIJKLMNOPQRSTUVXYZ'; 
            if ($allow_lowercase) $valid_charset .= 'abcdefghijklmnopqrstuvxyz'; 
            if ($allow_numbers) $valid_charset .= '0123456789'; 
            if ($allow_special) $valid_charset .= '!#$%&()*+-./;<=>@\_'; 
        } 
        # Find the charset length 
        $charset_length = strlen($valid_charset); 

        # If no chars is allowed, return false 
        if ($charset_length == 0) return false; 

        # Initialize the password and loop till we have all 
        $password = ""; 
        while(strlen($password) < $length) { 
            # Pull out a random char 
            $char = $valid_charset[mt_rand(0, ($charset_length-1))]; 
             
            # If similar is true, check if string contains mistakeable chars, add if accepted 
            if (($fix_similar && !strpos('O01lI5S', $char)) || !$fix_similar) $password .= $char; 
        } 


        # Return password 
        return $password; 
    } 


    function password_generate_pronouncable($length = 8) { 
        # Initialize valid char lists 
        $valid_consonant = 'bcdfghjkmnprstv'; 
        $valid_vowel = 'aeiouy'; 
        $valid_numbers = '0123456789'; 

        # Find the charset length 
        $consonant_length = strlen($valid_consonant); 
        $vowel_length = strlen($valid_vowel); 
        $numbers_length = strlen($valid_numbers); 

        # Initialize the password and loop till we have all 
        $password = ""; 
        while(strlen($password) < $length) { 
            # Pull out a random set of pronouncable chars 
            if (mt_rand(0, 2) != 1) $password .= $valid_consonant[mt_rand(0, ($consonant_length-1))].$valid_vowel[mt_rand(0, ($vowel_length-1))].$valid_consonant[mt_rand(0, ($consonant_length-1))]; 
            else $password .= $valid_numbers[mt_rand(0, ($numbers_length-1))]; 
        } 

        return substr($password, 0, $length); 
    } 
?>