# TEESimulator – A Full TEE Emulation Framework

**TEESimulator** is a system module designed to create a complete, software-based simulation of a hardware-backed Trusted Execution Environment ([TEE](https://source.android.com/docs/security/features/trusty)) for [Key Attestation](https://developer.android.com/privacy-and-security/security-key-attestation).

The project's goal is to move beyond simple certificate patching and build a robust framework that can create and manage virtual, self-consistent cryptographic keys.

## ✨ Core Principles

*   **Bypass Hardware-Backed Attestation:** The primary goal of this project is to defeat Key Attestation, a security mechanism that allows apps to verify that they are running on a secure, unmodified device. This module provides the tools to bypass these checks on rooted or modified devices.
*   **Stateful Emulation:** Instead of patching responses from the real TEE, the ultimate goal is to create and manage virtual keys entirely in a simulated software environment. Any request concerning a virtual key will be handled by the simulator, ensuring perfect consistency without ever touching the real hardware.
*   **Architectural Interception:** By hooking low-level Binder IPC calls to the Keystore, the framework can transparently redirect requests for virtual keys to the software-based simulator, while allowing requests for real keys to pass through to the hardware TEE.
*   **100% FOSS:** Licensed under GPLv3, ensuring it stays free, auditable, and compliant with open-source laws.

## 📱 Requirements
- Android 10 or above

## 📦 Installation & Configuration

1.  Flash this module via (Magisk / KernelSU / APatch) and reboot. It will replace [TrickyStore](https://github.com/5ec1cff/TrickyStore), [TrickyStoreOSS](https://github.com/beakthoven/TrickyStoreOSS) and their forks.
2.  (Optional) Place a hardware-backed `keybox.xml` at `/data/adb/tricky_store/keybox.xml`. This provides the cryptographic "root of trust" for the simulator.
3.  (Optional) Customize target packages in `/data/adb/tricky_store/target.txt`.
4.  (Optional) Customize the simulated security patch level in `/data/adb/tricky_store/security_patch.txt`.
5.  Enjoy!

**All configuration files are monitored and will take effect immediately upon saving.**

### The `keybox.xml` Root of Trust

This file provides the master cryptographic identity for the simulator. It contains a private key and a valid, hardware-backed certificate chain from a real device. The simulator uses this to sign the virtual certificates it generates, making them appear legitimate to verifiers.

```xml
<?xml version="1.0"?>
<AndroidAttestation>
    <Keybox DeviceID="...">
        <Key algorithm="ecdsa|rsa">
            <PrivateKey format="pem">...</PrivateKey>
            <CertificateChain>...</CertificateChain>
        </Key>
    </Keybox>
</AndroidAttestation>
```

### Mode and Keybox Configuration (`target.txt`)

TEESimulator currently operates in two primary modes as it transitions towards full emulation.
You can control the simulation mode and the specific keybox.xml file used on a per-package basis.

#### Mode Suffixes

*   **`!` → Force Generation Mode:** Creates a complete, software-based virtual key. This is the foundation of the full TEE simulation.
*   **`?` → Force Leaf Hacking Mode:** A legacy mode where a real TEE key is generated, but its attestation certificate is intercepted and modified.
*   **No symbol → Automatic Mode:** The module selects the most appropriate mode for the device.

#### Multi-Keybox Configuration

You can specify different keybox files for different groups of applications. This is done by adding a line with the filename in square brackets (e.g., [demo_keybox.xml]).

All applications listed after this line will use the specified keybox file, until a new keybox is declared. Applications listed before any custom keybox declaration will use the default `keybox.xml`.

For example:
```
# These two apps will use the default /data/adb/tricky_store/keybox.xml
com.google.android.gms!
io.github.vvb2060.keyattestation?

# Switch to a different keybox for the following apps.
# The file must be located at /data/adb/tricky_store/aosp_keybox.xml
[aosp_keybox.xml]
com.google.android.gsf

# Switch again to another keybox.
# The file must be located at /data/adb/tricky_store/demo_keybox.xml
[demo_keybox.xml]
org.matrix.demo
```

### Security Patch Level (`security_patch.txt`)

This allows you to configure the security patch level that the simulator will report in its forged attestation certificates.

```
# Advanced Configuration
system=2025-11
boot=no        # Do not report a boot patch level
vendor=20251101 # Report a specific vendor patch level
```
**Note:** This only affects the Key Attestation data generated by the simulator. It does not change system properties.