How to generate a random, unique, alphanumeric string in PHP

18 Feb, 2022
There are many ways to generate a random, unique, alphanumeric string in PHP which are given below: 
Using str_shuffle() Function: The str_shuffle() function is an inbuilt function in PHP and is used to randomly shuffle all the characters of a string passed to the function as a parameter. When a number is passed, it treats the number as the string and shuffles it. This function does not make any change in the original string or the number passed to it as a parameter. Instead, it returns a new string which is one of the possible permutations of the string passed to it in the parameter. Example:  
PHP
<?php // This function will return a random// string of specified lengthfunction random_strings($length_of_string){     // String of all alphanumeric character    $str_result = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';     // Shuffle the $str_result and returns substring    // of specified length    return substr(str_shuffle($str_result),                       0, $length_of_string);} // This function will generate// Random string of length 10echo random_strings(10); echo "\n"; // This function will generate// Random string of length 8echo random_strings(8); ?>
 
hnQVgxd4FE
6EsbCc53
 
Using md5() Function: The md5() function is used to calculate the MD5 hash of a string. Pass timestamp as a argument and md5 function will convert them into 32 bit characters Example:  
PHP
<?php // This function will return a random// string of specified lengthfunction random_strings($length_of_string) {         // md5 the timestamps and returns substring    // of specified length    return substr(md5(time()), 0, $length_of_string);} // This function will generate// Random string of length 10echo random_strings(10); echo "\n"; // This function will generate// Random string of length 8echo random_strings(8); ?>
 
12945f0845
12945f08
 
Using sha1() Function: This function calculates the sha-1 hash of a string. Pass timestamps as a argument and sha1() function will convert them into sha1- hash.Example:  
PHP
<?php   // This function will return  // A random string of specified length  function random_strings($length_of_string) {               // sha1 the timestamps and returns substring    // of specified length    return substr(sha1(time()), 0, $length_of_string);} // This function will generate// Random string of length 10echo  random_strings(10); echo "\n"; // This function will generate// Random string of length 8echo  random_strings(8); ?>
 
643f60c52d
643f60c5
 
Using randon_bytes() Function: This function generates cryptographically secure pseudo-random bytes. It returns a string containing the requested number of cryptographically secure random bytes. Use binehex () function to convert bytes into hexadecimal format.Example:  
PHP
<?php // This function will return// A random string of specified lengthfunction random_strings($length_of_string) {     // random_bytes returns number of bytes    // bin2hex converts them into hexadecimal format    return substr(bin2hex(random_bytes($length_of_string)),                                      0, $length_of_string);} // This function will generate// Random string of length 10echo random_strings(10); echo "\n"; // This function will generate// Random string of length 8echo random_strings(8); ?>
 
64713970f3
67b575a3
 
 
saurabh1990aror
surinderdawra388
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