# Potential of Homomorphic Encryption for Cloud Computing Use Cases in Manufacturing
## 4 Use Cases for Homomorphic Encryption for Cloud Computing in Manufacturing
### Contract Manufacturing for Chipsets  
The second use case enables anonymized cost determination for contract manufacturers in chip manufacturing using homomorphic encryption via a cloud platform. Due to the rising costs in the manufacturing of microchips, many companies in the semiconductor industry are abandoning their own chip manufacturing [46]. So-called fabless companies design and develop microchip technology, and then outsource the entire manufacturing to contract manufacturers, the so-called chip foundries. This is advantageous for chip developers, as setting up their own manufacturing involves significantly higher costs than just developing microchips [47]. The use case focuses on the process of evaluating the manufacturing and cost feasibility of producing a new chip design. For the chip manufacturers under consideration, the developed microchip technology is a unique feature, which must, therefore, be specially protected. Due to the existing dangers, such as theft of the technology, to which the chip design is exposed when manufacturing is outsourced, the chip developer focuses on the greatest possible data security [46]. While determining the feasibility of manufacturing, the chip developer's data should, therefore, remain encrypted throughout. However, for efficiency reasons, a digital and centralized platform for exchange between chip developers and contract manufacturers is to be used. This platform should both standardize the quotation process and be used for data exchange after conclusion of the contract. In the considered use case, the cloud initially has the function of a platform for the exchange between chip developers and the contract manufacturer. Similar cloud manufacturing platforms already exist and represent an Internet-based variant of contract manufacturing [48]. Due to the extensive resources offered by a cloud, the entire quotation calculation can be transferred to the cloud. At the same time, the accessibility of the cloud via the Internet allows easy access for exchange at any time. In the use case, a group of several chip developers is considered, who do not have their own manufacturing facilities and use a contract manufacturer that takes over the manufacturing of microchips for these developers. Since all products are semiconductors, the manufacturing requirements are similar for all chip developers. Due to the similar requirements for the cloud, which is used for the calculation of the costing model, among other things, a community cloud represents an efficient and cost-effective solution. Figure 8 shows the architecture and the data flow between the involved parties. In summary, the main task of the cloud is to provide a platform for data exchange between chip developers and the contract manufacturer. Due to the composition of the companies using the cloud platform, a community cloud is used. Encryption takes place  
Figure 8: Classification and cloud architecture for contract manufacturing of chipsets. using SWHE, and the use case is aimed at large enterprises. The selection of characteristic values is shown in the morphological box of the chip manufacturer use case Figure 8.  
Again, the three requirements security, time, and cost are fulfilled. First, as described above, data security is of high importance, as data might otherwise be visible for competitors. Second, offers must not be created in real time. Thus, the additional calculation time is not issue. Third, as the whole offer calculation is automized and a mid-prize cloud in form of a community cloud is used, costs are saved. As the architecture in Figure 8 shows, the process starts with the creation and provision of the costing model for quoting by the contract manufacturer. The model is defined on the basis of the manufacturing parameters for a given chip type and considers the contract manufacturer's costs and intended margins. The model is homomorphically encoded and transmitted to the cloud platform.