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50 lines
2.4 KiB
Markdown
50 lines
2.4 KiB
Markdown
| Supported Targets | ESP32 | ESP32-C2 | ESP32-C3 | ESP32-C6 | ESP32-S2 | ESP32-S3 |
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| ----------------- | ----- | -------- | -------- | -------- | -------- | -------- |
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# Encrypted Binary OTA
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This example demonstrates OTA updates with pre-encrypted binary using `esp_encrypted_img` component's APIs and tool.
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Pre-encrypted firmware binary must be hosted on OTA update server.
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This firmware will be fetched and then decrypted on device before being flashed.
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This allows firmware to remain `confidential` on the OTA update channel irrespective of underlying transport (e.g., non-TLS).
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## ESP Encrypted Image Abstraction Layer
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This example uses `esp_encrypted_img` component hosted at [idf-extra-components/esp_encrypted_img](https://github.com/espressif/idf-extra-components/blob/master/esp_encrypted_img) and available though the [IDF component manager](https://components.espressif.com/component/espressif/esp_encrypted_img).
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Please refer to its documentation [here](https://github.com/espressif/idf-extra-components/blob/master/esp_encrypted_img/README.md) for more details.
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## How to use the example
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To create self-signed certificate and key, refer to README.md in upper level 'examples' directory. This certificate should be flashed with binary as it will be used for connection with server.
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### Creating RSA key for encryption
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You can generate a public and private RSA key pair using following commands:
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`openssl genrsa -out rsa_key/private.pem 3072`
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This generates a 3072-bit RSA key pair, and writes them to a file.
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Private key is required for decryption process and is used as input to the `esp_encrypted_img` component. Private key can either be embedded into the firmware or stored in NVS.
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Encrypted image generation tool will derive public key (from private key) and use it for encryption purpose.
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* **NOTE:** We highly recommend the use of flash encryption or NVS encryption to protect the RSA Private Key on the device.
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* **NOTE:** RSA key provided in the example is for demonstration purpose only. We recommend to create a new key for production applications.
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## Build and Flash example
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```
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idf.py build flash
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```
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* An encrypted image is automatically generated by build system. Upload the generated encrypted image (`build/pre_encrypted_ota_secure.bin`) to a server for performing OTA update.
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## Configuration
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Refer the README.md in the parent directory for the setup details.
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