Description
array 
mcrypt_enc_get_supported_key_sizes ( resource td )
     Returns an array with the key sizes supported by the algorithm
     specified by the encryption descriptor. If it returns an empty
     array then all key sizes between 1 and
     mcrypt_enc_get_key_size() are supported by the
     algorithm.
    
     
Example 1. mcrypt_enc_get_supported_key_sizes() example 
<?php     $td = mcrypt_module_open('rijndael-256', '', 'ecb', '');     var_dump(mcrypt_enc_get_supported_key_sizes($td)); ?>
 |  
 
       This will print:
       array(3) {
  [0]=>
  int(16)
  [1]=>
  int(24)
  [2]=>
  int(32)
} |  
  |