I want to start off by saying I did not read the article; The topic surrounding secure devices while traveling has been on the rise in recent months so I will present some solutions which I believe all should take note off. I believe to obtain and maintain a truly private and secure mobile phone we must all be using a GrapheneOS device. However, for those of us who are still using iPhones I present solutions for you as well. Here are a few things to consider when traveling across borders:
GrapheneOS Devices
If you are even the slightest bit of a privacy enthusiast you likely don’t need an introduction to GrapheneOS so I will attempt to provide a succinct summary on why I believe GrapheneOS devices are the best phones to carry when traveling.
I believe GrapheneOS devices are the most private and secure mobile devices to have; Ironically they only work with Google Pixel devices, however this is not without good reason. Google Pixel devices offer superior hardware security than most Android devices on the market, which is why GrapheneOS will only work on Pixel devices.
GrapheneOS utilizes the robust hardware security features that Google Pixel devices offer such as the ability to re-lock the bootloader after installation. Typically, uploading a custom OS to an Android device requires you to unlock and disable the bootloader. After the OS is installed you must keep the bootloader disabled in order to continue using your custom ROM. This is horrible for your security. If someone has physical access to this device they can upload malicious software; likely without your knowledge. Having a locked/enabled bootloader is paramount to your privacy and security especially when crossing borders into foreign countries.
GrapheneOS has the upper-hand when it comes to this issue. After installation, not only do you re-lock the bootloader, but GrapheneOS will detect modifications to any of the Operating System partitions and prevent reading of any data whatsoever. The authenticity and integrity of the OS is always re-verified upon each boot. If you wanted to unlock the bootloader of a GrapheneOS device you will not be able to do so without completely erasing every piece of encrypted data on your device.
GrapheneOS has been tried against many of the forensic machines that Law Enforcement/ TSA/ Border Control use such as Cellebrite. To my knowledge at the time of writing, there have been no known cases in which Cellebrite was able to succeed in cracking a GrapheneOS device in a BFU (Before First Unlock) state.
BFU (Before First Unlock)
When you first boot up your phone, you are required to input your password to access your phone’s data. This is known as a BFU (Before First Unlock) state. After this initial “first boot” you enter your password which is then stored in your phone’s RAM. This is known as an AFU (After First Unlock) state. Storing your password in RAM is necessary because your device is constantly decrypting information on your disk in order for your device to “compute”. When your device is in this AFU state it is much easier for your device’s password to be confiscated because the password to decrypt your phone’s contents is stored in RAM. Simply rebooting your phone without entering your password will put your phone in a BFU state where it will remain until you put in your password. These same tips also apply to other devices such as laptop computers.
Strong Passwords
On the topic of BFU (Before First Unlock) it is important to talk about strong passwords. Although your phone may be in a BFU state if you have a weak password it is only a matter of a short while before your device is cracked. A typical 4 to 6 digit pin is trivial to crack. Use either a very long and complicated pin or a very long and complicated alphanumeric password/passphrase; preferably the latter. Your password doesn’t need to be super complicated just make sure it’s long and memorable.
iPhones
If traveling with an iPhone I highly recommend you look into Phone Pair Locking. For the sake of my fingers I will refer to Phone Pair Locking as “PPL” from now on. PPL was designed for businesses to deploy numerous iOS devices with the same configurations. PPL is done through a MacOS exclusive application known as “Apple Configurator”. Apple Configurator allows businesses to configure permissions as well as place restrictions on iOS devices. What does this mean for us? It means we can configure our iPhone so we never have to worry about forensics again. Note that PPL is best enabled on a new device because enabling this will result in a complete wipe of your phone and you will NOT be able to restore from a backup. PPL creates a trusted relationship between your iOS device and a MacOS computer. This means that the only computer you will ever be able to transfer data to while plugged in via cable is the computer which you have setup PPL on. PPL will not allow a forensics machine to analyze data from an iPhone. PPL will not allow a forensics machine to copy any form of data for later inspection. PPL eliminates the threat of any forensic machines from being able to access any data off your phone.
I apologize for keeping this section brief but there is more we need to consider. Do not travel with the same computer you have set up PPL on. That computer is your key into your device. Leave the key at home and forensics can never use your computer to access your phone’s data. PPL is NOT a replacement for strong passwords and BFU state, it is an additional feature which you should enable to ensure that your device remains secure. Another thing to consider is Apple Configurator is only available on MacOS devices. I assume you can use a MacOS Virtual Machine if you do not own a MacOS device, but I have not attempted this so I do not know. Unfortunately PPL is ONLY available for iOS devices. To my knowledge nothing similar to PPL exists for Android or GrapheneOS devices. Because of PPL I actually consider iPhones a decent option while traveling.
Additional tips
Preferably use a secondary device. Purchase a new device specifically for traveling and keep a very minimal amount of information (if any) on it. In the event Law Enforcement is not able to crack your device they may just outright confiscate it and you will have to say goodbye to your phone. Be wary of what clothing you wear and what stickers you have added to your devices (if any). If your clothing expresses political affiliation or you look like a crypto shill with BTC stickers on your laptop and a Bitcoin shirt and hat you may be probed and questioned by overly zealous Border Agents because “you are carrying more than 10 thousand dollars across the border”. This may result in confiscation and or secondary inspections. Try to wear plain clothing and remove or cover stickers that you think could possibly result in issues.
Conclusion
I would like to apologize for making this post extremely long, it turned out much longer than expected. Since I’ve opened this can of worms add a comment to this if you want me to write a full guide. I have excluded a lot of information in an effort to keep this post as short as possible. But if I write a guide I will include everything with absolutely no stops.
On pixel 9 (and maybe earlier) grapheneos devices, you can just disable the USB c port which is more secure than apple’s pairlocking. Combine that with a self destruct pin/password, your data is bulletproof.
I want to start off by saying I did not read the article; The topic surrounding secure devices while traveling has been on the rise in recent months so I will present some solutions which I believe all should take note off. I believe to obtain and maintain a truly private and secure mobile phone we must all be using a GrapheneOS device. However, for those of us who are still using iPhones I present solutions for you as well. Here are a few things to consider when traveling across borders:
If you are even the slightest bit of a privacy enthusiast you likely don’t need an introduction to GrapheneOS so I will attempt to provide a succinct summary on why I believe GrapheneOS devices are the best phones to carry when traveling.
I believe GrapheneOS devices are the most private and secure mobile devices to have; Ironically they only work with Google Pixel devices, however this is not without good reason. Google Pixel devices offer superior hardware security than most Android devices on the market, which is why GrapheneOS will only work on Pixel devices.
GrapheneOS utilizes the robust hardware security features that Google Pixel devices offer such as the ability to re-lock the bootloader after installation. Typically, uploading a custom OS to an Android device requires you to unlock and disable the bootloader. After the OS is installed you must keep the bootloader disabled in order to continue using your custom ROM. This is horrible for your security. If someone has physical access to this device they can upload malicious software; likely without your knowledge. Having a locked/enabled bootloader is paramount to your privacy and security especially when crossing borders into foreign countries.
GrapheneOS has the upper-hand when it comes to this issue. After installation, not only do you re-lock the bootloader, but GrapheneOS will detect modifications to any of the Operating System partitions and prevent reading of any data whatsoever. The authenticity and integrity of the OS is always re-verified upon each boot. If you wanted to unlock the bootloader of a GrapheneOS device you will not be able to do so without completely erasing every piece of encrypted data on your device.
GrapheneOS has been tried against many of the forensic machines that Law Enforcement/ TSA/ Border Control use such as Cellebrite. To my knowledge at the time of writing, there have been no known cases in which Cellebrite was able to succeed in cracking a GrapheneOS device in a BFU (Before First Unlock) state.
When you first boot up your phone, you are required to input your password to access your phone’s data. This is known as a BFU (Before First Unlock) state. After this initial “first boot” you enter your password which is then stored in your phone’s RAM. This is known as an AFU (After First Unlock) state. Storing your password in RAM is necessary because your device is constantly decrypting information on your disk in order for your device to “compute”. When your device is in this AFU state it is much easier for your device’s password to be confiscated because the password to decrypt your phone’s contents is stored in RAM. Simply rebooting your phone without entering your password will put your phone in a BFU state where it will remain until you put in your password. These same tips also apply to other devices such as laptop computers.
On the topic of BFU (Before First Unlock) it is important to talk about strong passwords. Although your phone may be in a BFU state if you have a weak password it is only a matter of a short while before your device is cracked. A typical 4 to 6 digit pin is trivial to crack. Use either a very long and complicated pin or a very long and complicated alphanumeric password/passphrase; preferably the latter. Your password doesn’t need to be super complicated just make sure it’s long and memorable.
If traveling with an iPhone I highly recommend you look into Phone Pair Locking. For the sake of my fingers I will refer to Phone Pair Locking as “PPL” from now on. PPL was designed for businesses to deploy numerous iOS devices with the same configurations. PPL is done through a MacOS exclusive application known as “Apple Configurator”. Apple Configurator allows businesses to configure permissions as well as place restrictions on iOS devices. What does this mean for us? It means we can configure our iPhone so we never have to worry about forensics again. Note that PPL is best enabled on a new device because enabling this will result in a complete wipe of your phone and you will NOT be able to restore from a backup. PPL creates a trusted relationship between your iOS device and a MacOS computer. This means that the only computer you will ever be able to transfer data to while plugged in via cable is the computer which you have setup PPL on. PPL will not allow a forensics machine to analyze data from an iPhone. PPL will not allow a forensics machine to copy any form of data for later inspection. PPL eliminates the threat of any forensic machines from being able to access any data off your phone.
I apologize for keeping this section brief but there is more we need to consider. Do not travel with the same computer you have set up PPL on. That computer is your key into your device. Leave the key at home and forensics can never use your computer to access your phone’s data. PPL is NOT a replacement for strong passwords and BFU state, it is an additional feature which you should enable to ensure that your device remains secure. Another thing to consider is Apple Configurator is only available on MacOS devices. I assume you can use a MacOS Virtual Machine if you do not own a MacOS device, but I have not attempted this so I do not know. Unfortunately PPL is ONLY available for iOS devices. To my knowledge nothing similar to PPL exists for Android or GrapheneOS devices. Because of PPL I actually consider iPhones a decent option while traveling.
Preferably use a secondary device. Purchase a new device specifically for traveling and keep a very minimal amount of information (if any) on it. In the event Law Enforcement is not able to crack your device they may just outright confiscate it and you will have to say goodbye to your phone. Be wary of what clothing you wear and what stickers you have added to your devices (if any). If your clothing expresses political affiliation or you look like a crypto shill with BTC stickers on your laptop and a Bitcoin shirt and hat you may be probed and questioned by overly zealous Border Agents because “you are carrying more than 10 thousand dollars across the border”. This may result in confiscation and or secondary inspections. Try to wear plain clothing and remove or cover stickers that you think could possibly result in issues.
I would like to apologize for making this post extremely long, it turned out much longer than expected. Since I’ve opened this can of worms add a comment to this if you want me to write a full guide. I have excluded a lot of information in an effort to keep this post as short as possible. But if I write a guide I will include everything with absolutely no stops.
On pixel 9 (and maybe earlier) grapheneos devices, you can just disable the USB c port which is more secure than apple’s pairlocking. Combine that with a self destruct pin/password, your data is bulletproof.