Cold-storage wallets have long been the cornerstone of cryptocurrency security. They keep private keys offline, protecting them from hackers and breaches that often afflict online exchanges. Traditional cold wallets often require cables, companion apps, PIN codes, seed phrases, and even multi-step confirmations on tiny screens with tiny buttons.
As a result, one of the persistent barriers to mass adoption of these cold wallets has been usability. While most features are critical for security, they feel cumbersome and unintuitive for everyday users – especially compared to the fluid ease of mobile payments or online banking apps.
This friction has historically limited cold storage wallets to a niche of more technically confident users, leaving the broader market reliant on custodial solutions that trade away sovereignty for convenience.
A Swiss technology company Tangem AG introduced a new type of cold storage device. Founded in Zug in 2017, Tangem developed a hardware wallet shaped like a credit card, equipped with a Samsung S3D350A chip, which incorporates a DRAM-based TRNG for private key generation, and an antenna for near-field communication (NFC).
Rather than connecting the wallet to a computer with a USB or turning on Bluetooth, users just tap the card against their smartphone’s NFC area to manage their assets and sign transactions.
This Tap to Sign tech echoes the everyday experience of using Apple Pay at a point-of-sale terminal; it leverages a familiar gesture to make an unfamiliar process more intuitive. The action is nearly identical: instead of a smartphone and a POS machine, users authenticate a blockchain transaction by tapping their Tangem card to their smartphones.
Deeper Dive into Tangem Technology
Most cold wallets rely on recovery seed phrases; lists of words that serve as a master backup if the device is lost. Long considered the backbone of crypto self-custody, seed phrases introduce hidden liabilities. They are easily copied, stolen, or lost, and once compromised, funds are irretrievable. For an industry riddled with heists, seed phrases unfortunately shift the burden of perfect secrecy onto users; an unrealistic expectation that has led to countless cases of theft and loss.
Tangem entirely changes this approach. Its wallets are sold in packs of two or three identical cards. During initialization, the cards exchange entropy using the Diffie-Hellman key exchange protocol to derive and share the key securely, never exposing it outside the secure element. The redundancy means that if one card is lost or destroyed, the others remain fully functional, sidestepping the fragile single point of failure that seed phrases create.
While this method addresses a key vulnerability in many stolen cryptocurrency cases, it also shifts responsibility. Without a written backup, losing all the cards results in permanent loss of access to the funds. This design sharply reduces the chance of remote compromise but makes the system unforgiving in edge cases. Tangem users must safeguard at least one card from the original pack indefinitely. In effect, the wallet changes the threat model from digital theft to physical durability and redundancy.
NFC and the Secure Element Anatomy
Tangem design relies on the same technology embedded in modern passports and bank cards. The card’s secure element chip has a CC EAL6+ certification, commonly used in financial applications.
When a user initiates a transaction through Tangem mobile app, it is confirmed with biometric authentication and finalized by tapping the card to the phone. Behind the scenes, the unsigned data is sent to the card over NFC. The chip signs it internally and returns the signed transaction, while the private key never leaves the device. The smartphone powers the card passively, eliminating the need for batteries and charging ports.
External security firms like Kudelski Security and Riscure have audited the wallet’s firmware, which is designed to be non-updatable. However, that immutability comes at a cost: if any flaws within the tech are ever discovered, the hardware cannot be patched; it can only be fully replaced.
Despite these issues, Tangem cards became popular among users seeking simplicity and physical redundancy. The card form factor is portable, durable, and familiar to anyone accustomed to contactless payments.
Industry Trends
What we see here is part of a wider market shift. The collapse of centralized exchanges such as FTX has driven more users toward self-custody. Sales of hardware wallets surged in 2023, and the industry has since been experimenting with designs that emphasize ease of use as much as security.
Other firms have also moved toward card-shaped wallets, and larger players like Ledger have released models with improved design and smartphone integration. Tangem’s focus on tap-to-sign authentication and elimination of seed phrases highlights one vision of the future: cold storage that feels as straightforward as making a contactless payment.
A number of hardware wallets now use tap-to-sign mechanics, borrowing from the contactless payments’ architecture. One of the earliest examples is TAPSIGNER, a Bitcoin-only card developed by Coinkite. It also looks like a standard bank card and uses NFC for signing transactions. Users simply tap the card to their phone to authorize a spend.
Another example is Keycard, developed by the Status project. Also card-shaped, it allows users to hold private keys offline and sign transactions with a tap. Keycard’s open SDK is particularly notable, as it enables third-party developers to integrate its tap-to-sign functionality into their apps, making it a flexible option for broader blockchain use cases.
Some other products take tap-to-sign beyond wallets into direct payments. Flexa’s Burner card is designed to work with retail point-of-sale systems. A user taps their crypto card at the terminal, enters a PIN, and authorizes a blockchain payment without needing a smartphone or internet connection. This highlights how tap-to-sign can bridge the gap between digital assets and traditional consumer payments.
Is This the Future of Finance?
For now, approach from Tangem is in the middle spectrum of crypto security – simpler than traditional devices, but with its own trade-offs. Its card-based system reduces the risk of seed phrase theft yet requires careful handling of multiple physical backups. The reliance on smartphones streamlines access but also concentrates trust in the app interface.
As regulators seek to contain risks from centralized platforms while leaving space for individual custody, solutions from companies like Tangem AG point toward a future where self-custody could become more accessible to mainstream users. Whether NFC-based wallets will define the standard depends on how well they can balance security, usability, and privacy in a steady-developing world of crypto finances.