function _i2osp($x, $xLen)
    {
        $x = $x->toBytes();
        if (strlen($x) > $xLen) {
            user_error('Integer too large');
            return false;
        }
        return str_pad($x, $xLen, chr(0), STR_PAD_LEFT);
    }
function _i2osp($x, $xLen)
    {
        $x = $x->toBytes();
        if (strlen($x) > $xLen) {
            user_error('Integer too large');
            return false;
        }
        return str_pad($x, $xLen, chr(0), STR_PAD_LEFT);
    }
function _i2osp ( $ x , $ xLen ) { $ x = $ x -> toBytes ( ) ; if ( strlen ( $ x ) > $ xLen ) { user_error ( 'Integer too large' ) ; return false ; } return str_pad ( $ x , $ xLen , chr ( 0 ) , STR_PAD_LEFT ) ; }
Integer-to-Octet-String primitive

See {@link http://tools.ietf.org/html/rfc3447#section-4.1 RFC3447#section-4.1}.

@access private
@param \phpseclib\Math\BigInteger $x
@param int $xLen
@return string
Integer - to - Octet - String primitive