OpenGuardian

This repo contains tools and data for reverse engineering the Medtronic GCM (Guardian Continuous Glucose Monitoring) and Insulin Pump systems.

Why?

1. Users should be able to access their own body data directly and offline, without having to rely on external servers.
2. The mobile apps are largely unusable, reflected in very low Google Play ratings (1.5–2.0 out of 5).
3. In several countries, there are no healthcare-supported alternative systems.

How can I help?

We are currently looking for developers who have Java, BTLE and some crypto experience. If you would like to help, then please join our Discord.

Sub-projects

• JadxProjects

  • it contains the JADX projects to reverse engineer the APK contents

• PythonConnector

  • python scripts to be used on a PC that can connect and talk to the devices
  • contains a full SAKE implementation!

• LogSniffer

  • PCAP GATT message decryptor and decoder

• OpenGuardian4

  • Java code for parsing and decoding already decrypted BT messages.
  • this is intended to be used in an Android app hopefully in the foreseeable future
  • limited support for GATT characteristics

• SakeRE

  • the Ghidra project to reverse engineer the Medtronic's crypto library called SAKE
  • using an older version of the library built for ARMv7 from the Minimed 2.1.0

• Data

  • decrypted SAKE "key databases"
  • logs from the frida Monitor script
  • GATT service & char information
  • sniffed BT traffic in pcap format

• FridaScripts

  • various scripts to be used with frida (including the Monitor)

• Docs

• Other various tools

  • log_decrypt

    • the app contains functionality to dump decrypted logs into a zip file for debugging with Medtronic's email support (?)
    • the algorithm has been reversed, after manually patching the public key in the APK, it can be decrypted and will contain juicy info for reversing

  • db_decrypt

    • scripts to dump the AndroidKeyStore, where the keys are stored for the app's databases

  • minimal API for CareLink Cloud

    • I have reversed the API where the data upload/download takes place
    • the code now has been integrated in some open-source projects, this is just a mirror (see carelink-python-client, xDripCareLinkFollower)

  • Sakeproxy

    • an Android application which uses the prebuilt SAKE libraries extracted from the original APKs
    • it provides a simple HTTP API and it can be used to perform the crypto functions without an actual device
    • only a temporary solution until we can fully reverse enginer the crypto library, but will be very useful for development
    • it only supports one user at a time

  • NativeSakeRE

    • a native android ELF that can load sake and call its exported functions
    • this is a painless experience (at least compared to what was before) and works very nicely with ghidra

  • SakeproxyClient

    • shitty arduino and python wrapper for the Sakeproxy HTTP API

  • ApkScan

    • mirrored batch APK downloader and decompiler
    • key db scanner