AEA OTA/IPSW decryption

Gets a key from an AEA (non OTA; for OTAs, use the key that is provided with your response, as they generally do not have embedded auth data).

pip3 install -r requirements.txt
python3 get_key.py <path to AEA>

Note: it is highly recommended to use a virtual environment:

python3 -m venv .env  # only needed once
source .env/bin/activate
pip3 install -r requirements.txt  # only needed once
python3 get_key.py <path to AEA>

aea decrypt -i <path to AEA> -o <decrypted output file> -key-value 'base64:<key in base64>'

For IPSWs, you will get the unwrapped file (ie. 090-34187-052.dmg.aea will decrypt to 090-34187-052.dmg).

For assets, you will get specially crafted AppleArchives (see next section).

Assets (including OTA updates) are constructed specially and cannot be extracted with standard (aa) tooling. They can be decrypted normally, which will result in an AppleArchive that is not extractable with aa (we will call these "asset archives"). aastuff must be used to extract them.

# Decrypt if necessary
aea decrypt -i <path to AEA> -o <decrypted asset archive> -key-value 'base64:<key in base64>'
./aastuff -i <decrypted asset archive> -o <output folder>

aastuff can also handle asset archives that are not already decrypted:

./aastuff -i <path to AEA> -o <output folder> -k <key in base64>

Run ./aastuff -h for full usage information.

aastuff uses AAAssetExtractor, functions from libAppleArchive in order to extract asset archives. However, it is a pretty barren API and does not offer things like selective extraction.

aastuff_standalone uses (mostly) standard libAppleArchive functions to extract asset archives. It offers things such as file listings and selective extraction, but is not fully validated against all possible asset archives.

For now, both are built and used in the same way. Once aastuff_standalone is fully functional and validated, aastuff will be deprecated.

• aea1 - Siguza

• Siguza - auth data parsing strategy, AppleArchive extraction sample code
• Nicolas - original HPKE code
• Snoolie - auth data parsing strategy
• Flagers - AppleArchive assistance