RFID blocking wallets, Faraday bags, and signal-blocking pouches are everywhere - but most people buying them aren't entirely sure what they're protecting against, whether the threat is real, or whether the product actually works. This post cuts through the noise.
What is RFID?
RFID stands for Radio Frequency Identification. It's a wireless technology that allows information to be read from a chip without physical contact - just by bringing a reader close to it. You interact with RFID every day without thinking about it: tapping your Eftpos card at a checkout, touching on with your AT HOP card, unlocking a door with a swipe card, or using a contactless key fob to unlock your car.
The chips in these devices transmit data over short distances using radio waves. Most everyday contactless cards operate at 13.56MHz (NFC - Near Field Communication), while older access cards and car key fobs typically use lower frequencies around 125kHz.
What is RFID Blocking?
RFID blocking refers to materials or products that prevent radio waves from reaching an RFID chip - effectively creating a shield that stops a reader from communicating with the chip inside. The principle is the same as a Faraday cage, named after physicist Michael Faraday, which uses a conductive material to block electromagnetic fields.
RFID blocking products work by surrounding your card, key fob, passport, or device in a conductive layer - typically metallic fabric, carbon fibre, or a foil lining - that absorbs or reflects the radio waves before they can reach the chip inside.
What is the Actual Threat?
The concern driving RFID blocking products is the possibility of RFID skimming - where a criminal uses a concealed reader to wirelessly steal data from your contactless cards or passport without your knowledge, simply by getting close enough to you in a crowd.
The honest answer is that the real-world risk varies significantly depending on what you're protecting:
- Contactless credit and debit cards - Modern contactless cards have built-in protections. Each transaction generates a unique cryptographic code that cannot be reused, so even if someone reads your card wirelessly, they cannot replay that data to make a fraudulent transaction. The practical risk of card skimming on modern Visa and Mastercard contactless cards is low. That said, some older cards and some non-bank cards have weaker protections.
- Passports - New Zealand and most modern passports contain an RFID chip storing your personal details and biometric data. The chip is protected by Basic Access Control (BAC) or Passive Authentication, meaning it can only be read when the passport is physically opened - a reader cannot silently skim a closed passport in your bag. The cover itself provides some shielding.
- Car key fobs - This is where RFID and signal blocking genuinely matters. Keyless entry car theft via relay attack is a documented and growing problem in New Zealand. Thieves use two devices - one near your front door to capture the signal from your key fob inside the house, and one near your car - to relay the signal and unlock and start the vehicle without ever touching the key. This attack works on a wide range of modern vehicles and has led to significant increases in keyless car theft.
- Access cards and security tokens - Corporate access cards, hotel key cards, and building entry credentials stored on RFID cards can potentially be cloned if they use older, less secure protocols. Protecting these with an RFID-blocking sleeve or wallet is a reasonable precaution, particularly for high-value access credentials.
What is a Faraday Bag?
A Faraday bag is a signal-blocking pouch or container that blocks all wireless signals - not just RFID, but also WiFi, Bluetooth, GPS, and cellular signals. The term comes from the Faraday cage principle and is used for products that provide broader signal isolation than a simple RFID-blocking wallet.
Faraday bags are used for several purposes:
- Key fob protection - Storing your car keys in a Faraday pouch at home prevents relay attacks by blocking the signal entirely. This is the simplest and most effective defence against keyless car theft.
- Device isolation - Security professionals, investigators, and government agencies use Faraday bags to prevent phones and laptops from receiving calls, messages, or remote commands while in transit or storage.
- Privacy protection - Blocking GPS tracking on phones and other devices for situations where you need to ensure a device cannot be located remotely.
- EMP protection - Larger Faraday bags and containers can protect sensitive electronics from electromagnetic pulses, which is relevant for emergency preparedness and protecting critical equipment.
Does RFID Blocking Actually Work?
Yes - when the product is made properly. The key variables are the shielding material, the frequency range it blocks, and whether the product fully encloses the item without gaps. A poorly made RFID wallet with thin foil and open seams will provide inconsistent protection. A well-made Faraday pouch with tested shielding and sealed seams will reliably block signals across the relevant frequency ranges.
When evaluating RFID blocking and Faraday products, look for:
- Specified attenuation in dB across relevant frequencies (13.56MHz for NFC cards and passports, 125kHz for older access cards, cellular and GPS frequencies for full-device Faraday bags)
- Fully sealed construction with no gaps at seams or openings
- Quality shielding material - metallic fabric or multi-layer construction for broader frequency coverage
- Tested and certified products from reputable manufacturers
Who Actually Needs RFID Blocking Products?
The honest answer is nuanced. For contactless payment cards, the risk is low enough that a standard wallet provides adequate protection for most people. For passports, the built-in protections mean a blocking sleeve is a precaution rather than a necessity for most travel.
Where RFID and signal blocking provides genuine, practical protection:
- Anyone with a keyless entry vehicle - a Faraday key fob pouch is a cheap and effective defence against relay attacks, and car theft in New Zealand is a real and documented problem.
- Security and IT professionals - protecting access credentials, security tokens, and devices from unwanted reads or remote access.
- Frequent travellers - passport sleeves and RFID-blocking travel wallets provide peace of mind in high-traffic environments.
- Organisations managing sensitive access credentials - protecting corporate access cards from cloning is a reasonable security control.
Trust Panda stocks a range of Faraday bags and signal-blocking products for individuals and organisations, from compact key fob guards through to large-format EMP protection bags. If you are unsure which product suits your needs, contact us and we will help you choose.
