WordPress Random name for uploaded files

randomize-uploaded-file-name.php

<?php

// randomize upload filenames 
function htg_randomize_uploaded_filename( $filename ) {

	// does it have an extension? grab it
    $ext  = empty( pathinfo( $filename )['extension'] ) ? '' : '.' . pathinfo( $filename )['extension'];

    // return the first 8 characters of the MD5 hash of the name, along with the extension
    return substr(md5($filename), 0, 8) . $ext;
}

add_filter( 'sanitize_file_name', 'htg_randomize_uploaded_filename', 10 );