Hardware wallets in New Zealand

Secure elements, EAL levels and what the numbers actually mean

Almost every hardware wallet page you will read throws around "EAL5+" and "EAL6+" as if they were horsepower figures. They are not. Common Criteria Evaluation Assurance Levels describe how rigorously a component was evaluated, not how strong it is in absolute terms. A chip certified to EAL6+ has been examined under a semi-formally verified design and tested against a defined set of physical attacks. It is a meaningful signal — the same class of silicon goes into passports and payment cards — but it is a statement about process, and the certificate covers the chip rather than the finished wallet.

The practical difference between EAL5+ and EAL6+ in this market is smaller than the marketing implies. It matters most in one scenario: an attacker has your physical device and is willing to spend serious money on laboratory equipment to extract the key from the silicon. For most people that is not the threat. If you are a public figure, a known large holder, or someone whose address leaked in a vendor data breach, it becomes considerably more relevant.

And certification is not a guarantee. The clearest illustration in recent memory came in July 2026, when Ledger's in-house research lab, Ledger Donjon, published a laser fault-injection attack against Tangem's cards. Tangem's chip carries an EAL6+ certificate. The researcher aimed a single nanosecond laser pulse at a specific area of the die, evaded the platform's own fault-detection countermeasures, and corrupted one conditional check in Tangem's firmware — which was enough to set the card's access password to a value of their choosing. The certificate was real; the implementation on top of it had a gap. Because Tangem's cards have no firmware update mechanism, every card in circulation is affected and none can be patched. Our Tangem review covers what that means in practice, including the fact that the attack needs the physical card, roughly US$250,000 of equipment, and leaves visible damage.

Open firmware versus certified silicon: the real trade-off

This is the genuine philosophical split in the category, and both sides ship products we are comfortable recommending.

The open camp — Trezor, BitBox, Keystone, Blockstream, and Coldcard with source-available code — publishes its firmware so that anyone can read it, and in some cases reproduce the build to confirm the binary on your device matches the published source. The argument is straightforward: security through inspection beats security through obscurity, and thousands of independent eyes will find things a single vendor's team misses. The cost is that some certified secure elements come with non-disclosure requirements that make full openness difficult, which historically pushed open-source devices toward less protected chips. Trezor has largely resolved that tension in its Safe line, and the Safe 7 goes further by pairing an auditable TROPIC01 chip with a conventional EAL6+ secure element and a separate microcontroller, so the seed is protected by three independent layers.

The closed camp is essentially Ledger. Its secure element applications and operating system are proprietary, and the company's argument is that the chip's certification, plus a dedicated internal attack lab, delivers more real security than public source review of a weaker chip would. There is substance to that — Ledger Donjon has found and published serious findings in competitors' products, which is not the behaviour of a company doing security theatre. But you are being asked to trust a company's word, and the company has now had two customer-data exposures: the July 2020 breach that leaked roughly 270,000 customers' names, phone numbers and home addresses, and a January 2026 incident through its payment processor Global-e. Neither touched a private key. Both handed a list of known crypto owners' street addresses to whoever wanted it.

Our position, for what it is worth: if you cannot decide, pick open firmware, because it is the choice you are least likely to regret and it costs you almost nothing. If you already own a Ledger, do not panic-replace it — replace the assumption that your shipping address is private.

Air-gapped devices and why QR codes matter

A conventional hardware wallet plugs into your computer over USB. That cable is a data path, and a data path is an attack surface — small, well-defended, but real. Air-gapped devices remove it entirely. The Keystone 3 Pro uses USB only for charging and communicates exclusively by displaying and scanning QR codes. The Coldcard Q can work through a microSD card and a built-in QR scanner. Jade has a camera for the same purpose.

The workflow sounds cumbersome and mostly isn't: your phone shows a QR code containing the unsigned transaction, you point the device at it, the device shows you what you are signing, you approve, and the device displays a QR code containing the signature which your phone then reads. Ten seconds, no cable, and no scenario in which a compromised computer talks directly to the thing holding your keys.

Is it worth it? For a first device, no — the added friction is more likely to make you avoid using the wallet than to save you from a USB exploit that has never been used against a retail holder. For a second device protecting a large position, or for anyone building multisig, air-gap is a genuinely valuable property and we grade for it.