AEA OTA/IPSW decryption

• get_key.py
  • Python 3.10+ (might work with older, but not tested)
  • requests
  • pyhpke
• aastuff
  • macOS 13+
  • macOS 14+ for HPKE support
• aastuff_standalone
  • macOS 12+
  • macOS 14+ for HPKE support

pip3 install -r requirements.txt

python3 -m venv .env  # only needed once
source .env/bin/activate
pip3 install -r requirements.txt  # only needed once

source .env/bin/activate

You can pass two options to the makefile:

• DEBUG=1: build debug (debug prints, no optimizations, debug information)
• HPKE=1: build with HPKE support (needs macOS 14.0+)

make [DEBUG=1] [HPKE=1]

Unwrap the decryption key using the data embedded in an AEA's auth data blob.

source .env/bin/activate  # if you used a virtual environment
python3 get_key.py <path to AEA>

aea decrypt -i <path to AEA> -o <decrypted output file> -key-value 'base64:<key in base64>'
# or
./aastuff -i <path to AEA> -o <decrypted output folder> -d -k <key in base64>
# or, to use the network to grab the private key
./aastuff -i <path to AEA> -o <decrypted output folder> -d -n

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 Apple Archives (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 Apple Archive 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, Apple Archive extraction sample code
• Nicolas - original HPKE code
• Snoolie - auth data parsing strategy
• Flagers - Apple Archive assistance