Getting Started with TrustFLEX for Firmware Validation

This page shows you how to validate your firmware (Secure Boot) using TrustFLEX. You will use Jupyter Notebook to configure the TrustFLEX device, then use an example project (from the Trust Platform DesignSuite) to verify the firmware.

TrustFLEX is a pre-configured and partially pre-provisioned secure element to ensure that a product with the consumables it uses, firmware it runs, accessories that support it, and the network nodes it connects to are not cloned, counterfeited, or tampered. It is one of the three ATECC608A sub-families (including Trust&GO and TrustCUSTOM) found on the CryptoAuth Trust Platform development kit.


The CryptoAuth Trust Platform includes hardware prototyping tools along with a unique design suite to accelerate the prototyping of commonly implemented use cases (e.g., IoT authentication, firmware validation (Secure Boot), IP protection, custom public key infrastructure, etc.). The presence of three sub-families allows for a wide variety of flexibility for implementation, based on the complexity of the application.


Hardware Tools

Tool About Purchase
CryptoAuth Trust Platform
Evaluation Kit

The CryptoAuth Trust Platform evaluation kit includes an on-board Embedded Debugger (EDBG).

Software Tools

Tool About Installers
Windows Linux Mac OSX
Integrated Development Environment
C/C++ Compiler
Trust Platform DesignSuite
Includes Anaconda Navigator & Jupyter Notebook

The Trust Platform Design Suite also includes example projects for the Atmel Studio 7 IDE.

1. TrustFLEX Devices

TrustFLEX devices (part number ATECC608A-TFLXTLS) are pre-configured and partially pre-provisioned Secure Element.

1.1 Features:

  • Cloud Platform Support: Google Cloud, AWS IoT, AWS GreenGrass, and Microsoft Azure
  • Secure Boot Firmware validation
  • Secure Over The Air (OTA) upgrade
  • Custom Public Key Infrastructure (PKI)
  • IP/Firmware protection
  • Accessory and Disposable authentication

1.2 Device Customization Process:

There are five steps involved in customizing the TrustFLEX device:

  1. Select a Pre-defined Use Case(s) from the TrustFLEX use case library.
  2. Generate the development keys and certificates using the Jupyter Notebook resource generator.
  3. Prototype the Use Case(s) in the Jupyter Notebook.
  4. Test the Use Case(s) on an embedded platform using the MPLAB® projects provided in the suite.
  5. Generate the secret exchange for production.

2. Open Jupyter Notebook

Jupyter Notebook is an application packaged along with other packages in the Anaconda Distribution. Jupyter Notebook is an open-source web application that allows you to create documents that contain code and narrative text that can be executed in place. It provides Graphical User Interface (GUI) elements, the ability to add images, and provides an interactive look that is absent in normal code files.

The cells of the Notebook can be used to write code or text using markdown. The code cells contain executable code and the text cells contain the explanation of the code's functionality.

Choose your operating system from the tabs below:


Select the Windows Start icon.


Select Notebook (trust_platform) in the recently added group.

  • If you don't see it, type "Notebook" in the search bar.

The Jupyter Notebook emulates the folder structure of the host computer.

If you are using macOS, Jupyter Notebook will default to your HOME directory. You will need to navigate to trust_platform/DesignTools to reach the folder structure shown below.

assets folder:

  • CryptoAuth Trust Platform board factory reset project.

Docs folder:

  • TrustFLEX data sheets.
  • CryptoAuth Trust Platform board users guide.
  • Detailed TrustFLEX use-case guides.

TrustFLEX folder:

  • Jupyter notebooks and c-based projects for TrustFLEX.

TrustnGO folder:

  • Jupyter notebooks and c-based projects for TrustnGO.
Click image to enlarge.

start_here.html file:

  • Local webpage filled with lots of useful Trust Platform info including:
    • Trust Platform family selection guide.
    • Step-by-step use-case guide for application developers.
      • Use-case transaction diagrams including Application Programming Interfaces (APIs) with links to their implementation in example code.
      • Secure element provisioning description.
      • Secure element slot configuration and descriptions.

3. TrustFLEX Resource Generator:

The Resource Generator Notebook supports the development of Cryptographic Keys, Custom Root, and Signer Keys to issue device certificates and prototype the TrustFLEX devices with development keys and certificates.

TrustFLEX devices come with pre-programmed certificates in slots 10, 11, and 12. Slots zero-four have pre-generated private keys, other than these mentioned slots all the other slots have no data in them.

The Resource Generator Notebook will create development keys and certificates for all slots that can be further customized. Keys and certificate chains are stored in the PC filesystem and not generated in a secure environment.

Note: This tool is used for development purposes only and not for mass production. The keys and certificate chains are not generated in a secure environment.

3.1 Setting up the Hardware:

  • Plug-in the CryptoAuth Trust Platform to the PC using the USB cable.
  • The Design Suite is set up such that it communicates with the TrustFLEX device only.

3.2 Using the Trust Platform Suite for TrustFLEX:

  • Open Jupyter Notebook, navigate to the TrustFLEX resource generator notebook, and click to open it.
    • Folder: …DesignTools\TrustFLEX\00_resource_generation\
    • File: TFLXTLS_resource_generator.ipynb

Crypto Resource Generator

  • Execute each cell using Cell > Run Cell and observe the output of each successfully executed code cell.
  • If the Notebook has already been executed before, then Kernel > Restart and Clean Output helps to start the refresh; the output of the script is shown.
  • Once all the cells are executed, you are prompted to choose between the MCHP certificate or a custom created certificate.

This enables you to select the certificate chain for the examples. If MCHP certificates are selected, then the resources would be generated to handle default MCHP certificates. If custom certificates are selected, then it would be prompted for information, such as Organization Name, to include in the custom certificates being generated.

  • Choose the required certificate by entering a number into the box
    • MCHP Certificate: "1"
    • Custom Certificate: "2"
    • For this example, enter the number 2 (custom certificate) in the certificate type box.

TrustFLEX devices only use custom certificates for the AWS custom PKI use-case. For all other TrustFLEX use-cases, this selection is irrelevant because they don't use certificates.

  • A prompt will open asking you to enter the Organization Name. Choose any name (or a random set of characters) but make sure the name does not exceed 24 characters.
  • Once the Organization name has been entered, the output will be as follows:
  • The Notebook will also generate a manifest file to be uploaded into the public cloud of your choice (Google GCP, AWS IoT, and soon to be supported, Microsoft Azure).

4. Use Case Prototyping:

The Trust Platform Suite supports multiple use cases like Firmware Validation (Secure Boot), IP protection, and Custom Public Key Infrastructure, etc. Here in this document, we will see further details about Secure Boot prototyping.

4.1 Firmware validation (Secure Boot) Prototyping:

Secure Boot feature assists the microcontroller in identifying fraudulent code installed. When this feature is implemented, the microcontroller will send the digest to the TrustFlex device. The TrustFlex device validates this information and responds to the host with a success or failure.

Here are the steps that will be required to complete this use case successfully:

  • Generate the resources using the Resource generation notebook as mentioned in section four.
  • Run Secure Boot code (through a Jupyter Notebook)
  • Run Secure Boot code (through an MPLAB ‘C’ project)

Note: The software installations and the links are already mentioned in the CryptoAuth Trust Platform User Guide.

4.1.1 Executing the Secure Boot Use Case using Jupyter Notebook:

  • From the launched Jupyter Notebook navigate to TFLXTLS_Use_Cases > notebooks > secureboot
  • Execute all the steps until 2.3.3, and once it is successfully executed, the SBoot Update button will appear. Click on the button and it will turn green or red based on the result.
  • Continue running the example till the end of the notebook, you will see an SBoot Verify button. Click on the button, if it turns green it is successful.
  • Once all the steps are successfully executed, proceed to the next step (open the example project in the MPLAB X IDE).

4.1.2 Program the CryptoAuth Trust Platform with the Secure Boot example project.

Make sure you have installed both the MPLAB X IDE and XC32 C compiler.

  • Launch MPLAB and open the example project by selecting File > Open Project.
  • Browse to the folder you downloaded the Trust Platform Design Suite to. You will find the Secure Boot example project in this folder:TFLXTLS_Use_Cases\c\firmware\
  • Select the TFLXTLS_example_SAMD21.X file, then click the Open Project button.
  • Double-click on the secureboot_verify.c file to open it and see the code responsible for verifying the firmware.
  • Program the CryptoAuth Trust Platform with the Secure Boot example project by right-clicking the project name in the projects window and selecting Make and Program Device.
  • The output window shows the progress of the make and program process. You will know the process is complete when you see the "Programming Complete" message.
  • Once the programming is complete, then the firmware will execute the Secure Boot operation. On successful completion of the operation, the Trust Platform status LED will start blinking.
    • Secure Boot Successful = LED blinks once every second
    • Secure Boot Unsuccessful = LED blinks five times every second
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