Defending side channel attacks in additive manufacturing systems
A novel methodology for providing security to maintain the confidentiality of additive manufacturing systems during the cyber-physical manufacturing process is featured. This solution is incorporated within the computer aided manufacturing tools such as slicing algorithms and the tool-path generation, which are in the cyber-domain. This effectively mitigates the cross domain physical-to-cyber domain attacks which can breach the confidentiality of the manufacturing system to leak valuable intellectual properties.
1. A physical process encryption system ( 100 ) for defending an additive manufacturing (“AM”) system against a side channel attack, wherein the AM system comprises a cyber domain and a physical domain having a manufacturing machine ( 106 ), wherein said encryption system ( 100 ) is machine-dependent, wherein data of the cyber domain comprises G-code as input to the manufacturing machine ( 106 ), wherein the side channel attack occurs when an attacker acquires analog emissions emanating from the machine ( 106 ) during the printing process to extract the G-code and reproduce the 3D model, wherein the encryption system ( 100 ) comprises:
a. a random pattern generator ( 102 ) comprising a hardware processor having an output, wherein the output comprises a plurality of random patterns that are machine-dependent redundant physical information;
b. a physical process encryption module ( 104 ), operatively coupled to the random pattern generator ( 102 ), wherein the physical process encryption module ( 104 ) uses the output of the random pattern generator ( 102 ) to encrypt the physical printing process, the physical process encryption module ( 104 ) comprising:
i. a memory storing a plurality of encryption schemes; and
ii. a processor, operatively coupled to the memory, configured to use the output of the random pattern generator to execute the plurality of encryption schemes to accomplish encryption of the physical printing process ( 102 ); and
c. a printer controller ( 108 ) operatively coupled to the physical process encryption module;
wherein the G-code is passed from the cyber domain to the physical process encryption module ( 104 ), wherein the plurality of random patterns are passed from the random pattern generator ( 102 ) to the physical process encryption module ( 104 ), which then encrypts the physical printing process by embedding the plurality of random patterns into the G-code according to an encryption scheme of the a plurality of encryption schemes, wherein the G-code is then transmitted to the printer controller ( 108 ) for execution, wherein as the G-code is executed, resulting analog emissions are altered according to the machine-dependent redundant physical information embedded, thus encrypting the physical printing process and rendering G-code extracted using the altered analog emissions by the attacker ineffective for reproducing the 3D model.
2. The encryption system ( 100 ) of claim 1 , wherein the G-code comprises lines of code providing a layer-by-layer description of a 3D model to be printed by the machine ( 106 ) via a printing process.
3. The encryption system ( 100 ) of claim 1 , wherein the machine-dependent redundant physical information embedded into the G-code comprises a plurality of random delays, wherein each random delay is added in between lines of code of the G-code, whereupon execution of the G-code, altered analog emissions emanate from the machine ( 106 ) as a result of the random delays.
4. The encryption system ( 100 ) of claim 1 further comprising one or more stepper motors ( 110 ), each operatively coupled to the physical process encryption module ( 104 ) and the printer controller ( 108 ), wherein the machine-dependent redundant physical information embedded into the G-code comprises a randomization of a movement of each stepper motor, wherein each randomization generates random noise, thereby altering analog emissions emanating from the machine ( 106 ).