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sdm-backend

★ 116 Open GitHub ↗

Backend server for Secure Dynamic Messaging (SDM). Supports decryption of PICCData, SDMENCFileData, and validation of SDMMAC. Compatible with NTAG 424 DNA (both variants). Written in Python 3 Flask. Pull requests welcome.

// repository documentation

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# Backend server for decoding Secure Unique NFC Message (SUN)

An example of Flask application which can decrypt data contained in NDEF "mirrors" and validate their AES-CMAC cryptographic signature. Implemented according to _AN12196 "NTAG 424 DNA and NTAG 424 DNA TagTamper features and hints"_.

**Pull requests welcome.**

*Note: NTAG — is a trademark of NXP B.V.*

*Note: This GitHub project is not affiliated with NXP B.V. in any way. Product names are mentioned here in order to inform about compatibility.*

## Demo
Check out the demo at [sdm.nfcdeveloper.com](https://sdm.nfcdeveloper.com/). This server is using blank authentication keys (all-zeros, factory default). You can use this server for testing and should work fine until you change the default factory keys on your tags.

## How to configure the tags?
We suggest using [NFC Developer App](https://nfcdeveloper.com/tag-app/tutorial/) for Android/iOS in order to configure the tags. This application will do most things "under the hood" and your tags will work out-of-the-box with this project.

## Contact
Feel free to reach me at hello@nfcdeveloper.com if you have any questions concerning this topic.

## How to test?
### Manual installation
1. Clone the repository
   ```
   apt install -y git
   git clone https://github.com/nfc-developer/sdm-backend.git
   cd sdm-backend
   ```
2. Setup the virtualenv
   ```
   apt install -y python3 python3-pip python3-venv
   python3 -m venv venv
   source venv/bin/activate
   ```
3. Install the required dependencies and copy example config:
   ```
   pip3 install -r requirements.txt
   cp config.dist.py config.py
   ```
4. Run Flask development server:
   ```
   python3 app.py --host 0.0.0.0 --port 5000
   ```
5. Visit [localhost:5000](http://127.0.0.1:5000/) and check out the examples.

### Using Docker
1. Launch sdm-backend on port 5000:
   ```
   # ensure to delete old version, if it exists
   docker rmi icedevml/sdm-backend:latest || true

# run sdm-backend
   docker run \
       -p 5000:80 \
       -e MASTER_KEY=00000000000000000000000000000000 \
       icedevml/sdm-backend:latest
   ```
2. Visit [localhost:5000](http://127.0.0.1:5000/) and check out the examples.

Note: If you are running production instance, the `MASTER_KEY` should be an unique 16 byte value (hex encoded). However, all-zeros key is perfectly fine for testing.

## Authors

* Michał Leszczyński (hello@nfcdeveloper.com)

Feel free to contact if you have any questions.

sdm-backend

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