43 lines
1.5 KiB
Markdown
43 lines
1.5 KiB
Markdown
# ESP Encrypted Image Abstraction Layer
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This component provides an API interface to decrypt data defined in "ESP Encrypted Image" format. This format is as specified at [Image Format](#image-format)
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This component can help in integrating pre encrypted firmware in over-the-air updates. Additionally, this component can also be used for other use-cases which requires addition of encryption layer for custom data.
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## Image Format
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```c
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typedef struct {
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char magic[4];
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char enc_gcm[384];
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char iv[16];
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char bin_size[4];
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char auth[16];
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char extra_header[88];
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} pre_enc_bin_header;
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```
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The above struct represents encrypted image header.
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Note:
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* RSA-3072 key is provided to the tool externally. You can generate RSA key pair using following command:
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`openssl genrsa -out rsa_key/private.pem 3072`
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* AES-GCM key and IV are generated by the tool itself.
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## Tool Info
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This component also contains tool ([esp_enc_img_gen.py](https://github.com/espressif/idf-extra-components/blob/master/esp_encrypted_img/tools/esp_enc_img_gen.py)) to generate encrypted images using RSA3072 public key.
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To know more about the tool, use command:
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`python esp_enc_img-gen.py --help`
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## API Reference
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To learn more about how to use this component, please check API Documentation from header file [esp_encrypted_img.h](https://github.com/espressif/idf-extra-components/blob/master/esp_encrypted_img/include/esp_encrypted_img.h)
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