Abstract: Secure streaming method in a numerically controlled manufacturing system, where the 3D file of the 3D object such as a CAD file or STL file is not sent to the manufacturing machine, but is kept in asecured system. Instead, only the instructions for controlling the manufacturing machine (e.g., so called G-codes) are streamed to the manufacturing machine. Such instructions are secured so that only a specific manufacturing machine can make use of them. To this end, the set of instructions may be encoded, e.g., hashed on a secure server, using a server hash table while the manufacturing machine is provided with a local lookup hash table that is synchronized, e.g., loosely synchronized with the serve's hash table for converting the hashed instructions back to instructions suitable for operating the manufacturing machine.