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Reverse Engineered VAS Protocol Specification

Research by Grayson Martin
Last Updated 7/8/23

Introduction

Value Added Services (VAS) is the protocol used by NFC capable passes in Apple Wallet. Access to this protocol is heavily restricted on both the device end (a special certificate issued by Apple is required to create these passes) and the reader end (NDA enforced confidentiality). As such, a desire arose to better understand the protocol in order to explore additional use cases and examine its cryptographic integrity. There are gaps in understanding in certain parts of this protocol, however this document contains the minimum necessary understanding to automatically select, read data from, and decrypt a pass.

Importantly, this specification does not enable a malicious actor to read the data from a pass for which they do not have both the reader's private key, and the pass type identifier. Imp

Author: https://www.cyanhall.com/

1. The Layer Tree

Core Animation's original name is Layer Kit

Core Animation is a compositing engine; its job is to compose different pieces of visual content on the screen, and to do so as fast as possible. The content in question is divided into individual layers stored in a hierarchy known as the layer tree. This tree forms the underpinning for all of UIKit, and for everything that you see on the screen in an iOS application.

In UIView, tasks such as rendering, layout and animation are all managed by a Core Animation class called CALayer. The only major feature of UIView that isn’t handled by CALayer is user interaction.

There are four hierarchies, each performing a different role:

This is a temporary workaround to have etcd listening on all interfaces so you can access it from docker containers.

Add a local etcd unit file

Create a file called /media/state/units/etcd-local.service that has the following contents:

[Unit]
Description=etcd local

Using HockeySDK as an example

Download HockeySDK 3.0.0
Run these commands:

ARCH=armv7
FRAMEWORK_DIRECTORY="${HOME}/Downloads/HockeySDK-iOS-3/HockeySDK.embeddedframework"
FRAMEWORK_NAME=$(basename `echo "${FRAMEWORK_DIRECTORY}"/*.framework` .framework)

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

	# Use systemd for managing NVIDIA driver suspend in drivers ====>>> PRIOR to version 470 <<<=====
	# https://download.nvidia.com/XFree86/Linux-x86_64/450.66/README/powermanagement.html
	# https://forums.developer.nvidia.com/t/unable-to-set-nvidia-kernel-module-parameters/161306
	# Please note: In Fedora Linux you may need to just install the xorg-x11-drv-nvidia-power pakage
	# as sugested by @goombah88 in the comments below.

	TMP_PATH=/var/tmp
	TMPL_PATH=/usr/share/doc/nvidia-driver-460/

	echo "options nvidia NVreg_PreserveVideoMemoryAllocations=1 NVreg_TemporaryFilePath=${TMP_PATH}" \| sudo tee /etc/modprobe.d/nvidia-power-management.conf

	FROM killbill/killbill:0.20.0
	ADD kpm.yml /var/lib/killbill/kpm.yml

	# Patch to respect X-Fowarded-Proto and others when running with ELB
	ADD server.xml.patch ./
	RUN patch -p1 < server.xml.patch

	# Script that setup traps to respect docker stop commands and stop catalina
	ADD fargate-killbill.sh ./

	sudo pip install virtualenv

	brew install boost cppunit fftw gsl libusb orc qt qwt sdl sip swig zeromq wxpython

	( cd /usr/local/include && curl -LO https://github.com/zeromq/cppzmq/raw/master/zmq.hpp)

	curl -L http://sourceforge.net/projects/pyqt/files/PyQt4/PyQt-4.11.2/PyQt-mac-gpl-4.11.2.tar.gz \| tar zxvf -
	cd PyQt-mac-gpl-4.11.2/
	python configure-ng.py
	make -j2

	// Open Script Editor and Export this as an Application
	//
	// Then drop a keynote file on it in the Finder and it will properly resize
	// and rotate everything so the Keynote file becomes usable as a prototype
	// in the iPhone keynote app

	// rotateDocument exported function
	//
	// Accepts a Keynote document and will rotate
	// all the slides and elements in the slide 90 degrees

	# Demo http://ascii.io/a/3019

	# build
	gdbb () {

	# build with debug flags
	go build -gcflags "-N -l" -o out

	# make sure the build didn't fail
	if [ $? != 0 ]; then return; fi