How RFID Protection Works
Most modern payment cards, hotel keycards, and passport chips communicate over a short-range radio signal. That convenience also creates exposure. Here is how it works, and how Alpine Rivers® products defend against it.
What contactless cards actually do
A contactless card contains a small antenna and a chip. When the card is held near a reader, the reader emits a radio field. The antenna picks up that field, powers the chip, and transmits the data the reader requests. No physical contact. No keystrokes. No PIN at low values.
The standard frequency for most consumer contactless cards is 13.56 MHz. That includes Visa payWave, Mastercard PayPass, American Express ExpressPay, most modern hotel keycards, and the chip layer of e-passports.
What skimming looks like in practice
A skimmer is any device that emits the right radio field, prompts the card to respond, and captures the response. Skimmers can be:
- Hand-held units the size of a phone, walked past a bag or a back pocket on public transit
- Hidden inside a clipboard, a backpack, or a coat sleeve
- Mounted inside legitimate-looking payment terminals or building entry points
The card does not need to leave your pocket. It does not need to be held up. Range is short, but in a crowded space, short is enough.
How a Faraday cage stops the read
A Faraday cage is a continuous conductive enclosure. When a radio signal hits the outside of the cage, currents in the conductive layer cancel the field inside. The card never sees the reader. It cannot respond to a signal it cannot detect.
Every Alpine Rivers® product wraps cards in a multi-layer shielded barrier built on this principle. The card and case work together. The card stays usable when removed for a tap. It stays quiet while inside.
What Alpine Rivers® products do
- Sleeves enclose a single card on every face, including the open edge
- Money belts and neck wallets enclose multiple cards inside a shielded compartment, with the shielding integrated into the wall of the compartment, not just a flap
- RFID Blocking Cards add a passive shielding layer for travelers who prefer to keep their existing wallet
No layered barrier is absolute. We do not claim any product blocks every conceivable attack at every conceivable angle. We claim that for the threats travelers actually face, the math is on your side when the cards are inside.
Read about the specific frequency and why it matters in Why 13.56 MHz Is the Only Frequency That Matters.