Bootloader Spoofer

Spoofs a locked bootloader state for local attestation checks. Only enable it for apps that merely verify whether the bootloader is unlocked. Avoid hooking Google apps or the system framework unless you want Play Integrity checks to fail. If an app sends attestation certificates to a secure backend for verification, this module will not help and becomes ineffective.

Supports devices with broken TEE. This module is intended only for local attestation. For online attestation, use TrickyStore instead.

This project was made possible thanks to chiteroman and 5ec1cff.

Modes

Selectable in the UI; persisted to mode.txt in the module's data dir.

leaf_hack (requires a working TEE)

Lets the real AndroidKeyStore generate the leaf, then in engineGetCertificateChain rewrites the leaf's RoT extension to claim verified-boot green / locked / state=0 and re-signs the leaf with the keybox intermediate's private key. The rest of the chain is replaced with the keybox CA chain.

This is the cleanest path: leaf serial number, validity period, subject, public key all come from the real cert. Only the RoT bytes change.

cert_generate (works on broken TEE)

Generates a fresh KeyPair in AndroidOpenSSL / Conscrypt (skipping AndroidKeyStore), builds the leaf cert from scratch with a full RoT extension (purpose, algorithm, keySize, digest, ecCurve, noAuthRequired, origin, verifiedBoot fields, OS version, OS patch level, applicationID, vendor patch level, boot patch level), signs with the keybox intermediate. Caches chain by KeystoreAlias so engineGetCertificateChain(alias) returns the synthesized chain on later lookup.

Does not require AndroidKeyStore to produce a real chain; works when keymaster HAL / TEE is broken or absent.

Limitations vs leaf-hack:

• The generated keypair is not actually in the AndroidKeyStore. Apps that re-fetch via KeyStore.getEntry(alias) get null.
• KeyInfo.isInsideSecureHardware() is not hooked; returns the device's real value (false on broken TEE, so app may know).
• applicationID is best-effort; built from the current process's own package signatures.

Keybox

Ships with the public Google Android Software Attestation Root test keybox (the same EC + RSA keys/certs every prior fork embeds). These are public, not TEE-backed, and will not beat any online check that validates against Google's hardware attestation root or revocation list. Local attestation only.

Supply your own

XML format (TrickyStore-compatible subset):

<?xml version="1.0"?>
<AndroidAttestation>
  <NumberOfKeyboxes>1</NumberOfKeyboxes>
  <Keybox DeviceID="any">
    <Key algorithm="ecdsa">
      <PrivateKey format="pem">-----BEGIN EC PRIVATE KEY-----
... your EC private key ...
-----END EC PRIVATE KEY-----</PrivateKey>
      <CertificateChain>
        <NumberOfCertificates>3</NumberOfCertificates>
        <Certificate format="pem">-----BEGIN CERTIFICATE-----
... intermediate ...
-----END CERTIFICATE-----</Certificate>
        <Certificate format="pem">-----BEGIN CERTIFICATE-----
... root ...
-----END CERTIFICATE-----</Certificate>
      </CertificateChain>
    </Key>
    <Key algorithm="rsa">
      <PrivateKey format="pem">... RSA private key ...</PrivateKey>
      <CertificateChain>
        ... RSA chain ...
      </CertificateChain>
    </Key>
  </Keybox>
</AndroidAttestation>

Build (local)

gradle :app:assembleRelease