What is a Faraday bag and what can it do?¶

A Faraday bag is a shielded container designed to reduce or block radio-frequency communication with a device placed inside it.

Evidential caution: that putting a phone in a Faraday bag automatically preserves it perfectly. The bag may reduce mobile, Wi-Fi, Bluetooth and other radio connections, but effectiveness depends on the bag, its condition, how it is sealed and the frequencies involved.

What this means¶

A Faraday bag can help reduce the risk of remote access, remote wiping, incoming messages, synchronisation or other wireless communication.

Before placing a device inside, record the original state. Capture the screen, power, battery, network indicators, open applications and visible notifications.

Be aware that moving and handling the device may cause the screen to lock, wake, rotate or display new information.

A damaged, poorly sealed or incorrectly used bag may provide incomplete isolation. Cables passing into the bag can also defeat the shielding.

What to check or do next¶

• Where possible, test or verify the bag using approved local procedures, without repeatedly removing the device.
• Record when the device was placed inside, by whom, the bag used and any observed change.

Evidential limits¶

It does not power the device off. The device may continue running, changing internally, draining its battery or attempting to reconnect.

Do not assume that the bag stops every communication method. Wired connections, internal timers and already received commands may still affect the device.