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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.

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), extract the protected model and any supporting files. Double-click the project archive (.mlproj) in the Current Folder browser and specify the destination folder. Alternatively, right-click on the project archive and click Extract Here. The project opens, and the extracted files are in a new folder named after the project archive.

  • 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 Callbacks for Customized Model Behavior.

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 access the read-only view, you must have access to the licenses used in the protected model. If available, the protected model report shows the required licenses.

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.

Reference Protected Model

To reference a protected model:

  1. Ensure that the protected model is on the MATLAB path.

  2. If you have a harness model, copy the Model block from the harness model into your model. Otherwise, reference the protected model in a new Model block. Open the Block Parameters dialog box and enter the name of the protected model in the Model name field.

    When a Model block references a protected model, the Simulation mode of the block becomes Accelerator. You cannot change this mode or use this Model block in External mode.

  3. If the protected model is password protected, right-click the protected-model badge icon on the Model block and click Authorize. In the Model view box, enter the password, then click OK.

  4. Connect signal lines to the Model block that match its input and output port requirements. See Model Reference Interface and Boundary.

    Note that the protected model cannot use noninlined S-functions directly or indirectly.

  5. Provide any needed model argument values. See Parameterize a Referenced Model.

If you plan to simulate the protected model, use the same platform used to create the protected model. The software stores the protected model as a compiled MEX binary.

Use Models Protected in Previous Releases

Check that the Simulink release you are using supports the protected model.

If available, the protected model report shows the release versions used to create the protected model. Use the same Simulink release that was used to create the protected model unless the protected model also supports later releases, as described by this table.

Modeling RequirementCross-Release Protected Model Support
Read-only view

Supported with limitations — R2019a and later releases

  • Protected model must have been created in R2018b or a later release.

Simulation in normal mode

Supported with limitations — R2019a and later releases

  • Protected model must have been created in R2018b or a later release.

Simulation in accelerator mode

Supported with limitations — R2020a and later releases

  • Protected model must have been created in R2018b or a later release.

  • You must directly simulate the parent of the protected model. Simulating a model hierarchy that contains the parent model as a referenced model is not supported. To interactively simulate the parent model, you must open it as the top model in its own window. For more information, see Navigate Model Hierarchies.

  • The protected model must use Just-in-Time acceleration and must not require C code generation. For more information on acceleration modes, see How Acceleration Modes Work.

Simulation in SIL or PIL mode

Supported with limitations — R2020b and later releases

  • Protected model contains ERT, ERT-based, AUTOSAR, or GRT code generated in R2018b or a later release. You can run Model block SIL and PIL simulations that reference the protected model. For more information, see Use Protected Models from Previous Releases to Perform SIL Testing and Generate Code (Embedded Coder).

    If ERT or AUTOSAR code in the protected model requires shared utility code, use sharedCodeUpdate (Embedded Coder) to copy the required code to an existing shared utility code folder. For more information, see Cross-Release Shared Utility Code Reuse (Embedded Coder).

  • You cannot use Simulink.ModelReference.ProtectedModel.addTarget or Simulink.ModelReference.ProtectedModel.removeTarget to add or remove generated code from a protected model created in a different release.

Simulation in rapid accelerator modeNot supported
Code generation

Supported with limitations — R2020b and later releases

  • Protected model contains ERT, ERT-based, AUTOSAR, or GRT code generated in R2018b or a later release, with a Model reference code interface. For more information, see Use Protected Models from Previous Releases to Perform SIL Testing and Generate Code (Embedded Coder).

    If ERT or AUTOSAR code in the protected model requires shared utility code, use sharedCodeUpdate (Embedded Coder) to copy the required code to an existing shared utility code folder. For more information, see Cross-Release Shared Utility Code Reuse (Embedded Coder).

  • You cannot use Simulink.ModelReference.ProtectedModel.addTarget or Simulink.ModelReference.ProtectedModel.removeTarget to add or remove generated code from a protected model created in a different release.

See Also

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