How do I change just the password protected text – not the form

I have gone through the various available, mostly old, posts that show solutions to changing the password protected text but this one does not work with twenty thirteen:

function change_pw_text($content) {
$content = str_replace(
'This content is password protected for Stratamp employees',
$content);
return $content;
}
add_filter('the_content','change_pw_text');

and this one works but disables the form’s functionality:

add_filter( 'the_password_form', 'custom_password_form' );
function custom_password_form() {
global $post;
$label = 'pwbox-'.( empty( $post->ID ) ? rand() : $post->ID );
$o = '<form class="protected-post-form" action="' . get_option('siteurl') . '/wp-pass.php" method="post">
' . __( "<h1>Password Protected Page Content</h1>" ) . '
' . __( "This post is password protected. To view it please enter your password below:" ) . '
<label for="' . $label . '">' . __( "Password:" ) . ' </label><input name="post_password" id="' . $label . '" type="password" size="20" /><input type="submit" name="Submit" value="' . esc_attr__( "Login" ) . '" />
</form>
';
return $o;

I need to change this text “This post is password protected. To view it please enter your password below:” because the page is not a post.

I don’t need to change the form’s input field or its “Password” text and Submit button.

Charles