# ESP Encrypted Image Abstraction Layer 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) 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. ## Image Format ![Image Format](https://raw.githubusercontent.com/espressif/idf-extra-components/master/esp_encrypted_img/image_format.png) ```c typedef struct { char magic[4]; char enc_gcm[384]; char iv[16]; char bin_size[4]; char auth[16]; char extra_header[88]; } pre_enc_bin_header; ``` The above struct represents encrypted image header. Note: * RSA-3072 key is provided to the tool externally. You can generate RSA key pair using following command: `openssl genrsa -out rsa_key/private.pem 3072` * AES-GCM key and IV are generated by the tool itself. ## Tool Info 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. To know more about the tool, use command: `python esp_enc_img-gen.py --help` ## API Reference 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)
idf.py add-dependency "espressif/esp_encrypted_img^2.0.2"