Reference Protected Models from Third Parties

To deliver a model without revealing its intellectual property, third parties can protect the model before delivery. A protected model is a referenced model that does not support editing. The protected model author chooses whether to enable read-only view, simulation, code generation, and password protection. When an operation is password-protected, the AES-256 encryption technology protects the supporting file contents.

Note

Creating a protected model requires a Simulink^® Coder™ license.

To identify protected models, look for:

Files in the MATLAB^® Current Folder browser with a badge icon and an .slxp extension. Protected models do not appear in the model hierarchy in the Model Explorer.
Model blocks in the Simulink Editor with a badge icon in the lower left corner:

If available, a protected model report describes the supported functionality. To open the report, use one of these options:

In the MATLAB Current Folder browser, right-click the protected model and click Open Report.
In the Simulink Editor, right-click the protected-model badge icon on the Model block and click Display Report.

Alternatively, use the slxpinfo function. This function provides high-level information about the protected model even when the report is unavailable.

Load Supporting Files for Protected Model

You may receive the protected model on its own, in a project archive, or in a package.

If you receive a project archive (.mlproj), double-click the project archive in the Current Folder browser and specify the destination folder. Alternatively, right-click the project archive and click Extract Here. The project opens, and the extracted files are in a new folder named after the project archive. Optionally, reference the protected model project from another project. For more information, see Componentize Large Projects.

If you receive a protected model or supporting files by another method, follow any provided instructions. For example, you might need to load a MAT file that contains workspace definitions. You can configure a callback function, such as LoadFcn, to load the MAT file automatically. See Customize Model Behavior with Callbacks.

Verify Digital Signature of Protected Model

If the author signed the protected model, verify the digital signature. In the Current Folder browser, double-click the protected model. In the Details pane, the Signed by field indicates the publisher that signed the model and whether the signature is verified by a trusted certificate authority. Verification fails in the following cases:

The protected model was changed after it was signed.
The protected model was not signed.
The protected model was signed with an expired certificate.
The protected model was self-signed with a certificate issued by the author.
The protected model was signed with a missing or invalid certificate.
The certificate of the CA is missing in your system or is invalid.

To verify the signature on protected models by default, in the Simulink Preferences dialog box, select Verify digital signature of protected model before opening.

View Protected Model Contents

Web view allows you to view this protected model information:

System contents
Block parameters
Signal properties

To open the read-only view, you can double-click the Model block referencing the protected model or the .slxp file in the Current Folder browser. If the read-only view is password protected, right-click the protected-model badge icon and select Authorize. In the Model view box, enter the password, then click OK.

You can navigate the model hierarchy by double-clicking Model or Subsystem blocks. Alternatively, you can navigate to the View All tab and select the system that you want to view. You cannot view the content of protected referenced models in the protected model.

To view block parameters and signal properties, select a block or a signal line, respectively.

To search in Web view, click the search button, then enter the name or value that you want to search in the box that appears. The elements of the model that the search returns appear highlighted. The search results include the name and parent of each returned element.

Test Protected Model in Isolated Environment

With the protected model, you may receive a harness model, which typically has the suffix _harness. A harness model provides an isolated environment for you to test the protected model. If any supporting files are missing, simulating or generating code for the harness model can help identify them.

To create a harness model, right-click the protected model file in the Current Folder browser, then click Create Harness Model. The created harness model is set up for simulation of the protected model.