> For the complete documentation index, see [llms.txt](https://docs.voting.works/vxsuite-tdp-v4/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.voting.works/vxsuite-tdp-v4/software-installation/imaging-machines/verifying-the-image-installed-on-a-machine.md). # Verifying the Image Installed on a Machine ## Signed Hash Validation Once a machine has been imaged with a signed image, you can verify the system hash against the hash of what was built and signed during the Trusted Build process. To perform this verification, VotingWorks provides Signed Hash Validation. See [Signed Hash Validation](/vxsuite-tdp-v4/readme/signed-hash-validation.md) for details. Note: On older releases (v4.0.1 and earlier), the Secure Boot signing process only output a SHA256 hash value. That hash value needs to be converted to a base64 encoded value to match what is provided by Signed Hash Validation. That can be accomplished with the following command: ``` echo HASH | xxd -r -p | base64 ``` ## vx-iso The system hash can also be computed from outside the application, using a vx-iso USB drive as described under [Preparing USB Drives for Imaging](/vxsuite-tdp-v4/software-installation/imaging-machines/preparing-usb-drives-for-imaging.md). The instructions for this process are as follows: 1. Connect the vx-iso USB drive to a machine after the machine has been successfully imaged with the target software image. 2. Power the machine on. The machine will auto-boot from the vx-iso USB drive. 3. If the machine in question does not have a keyboard, connect a keyboard. 4. Select the option to "Compute System Hash". This runs an open-source script that itself uses standard, non-proprietary, open-source tools to compute a system hash. The script source code is available at this public URL: . A snapshot of the script source code has also been included for the test lab under `software-docs/compute-system-hash.sh`. 5. The hash will be displayed in base64 format. Check this hash against the EAC-published hash for the target software image. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.voting.works/vxsuite-tdp-v4/software-installation/imaging-machines/verifying-the-image-installed-on-a-machine.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.