Tangem and Mitilena: Pros and Cons

Carry a card around and sooner or later you will lose it. With Tangem, you cannot add another backup card some time after your purchase. It is technically impossible. With Mitilena, you can do it whenever you want.

If you own a Tangem, you’re stuck. Yes, the second card from the set is at home. But now it is the only one left. You cannot duplicate it: the chip is sealed, and backup setup is a one-time deal. Adding a replacement card to an existing set is technically impossible. From this point on, your entire balance depends on one piece of hardware: if it cracks when bent or deteriorates over time, no laboratory in the world can restore your access.

With Mitilena, a lost card does not mean a lost wallet: tap a spare NFC card or sticker against your phone and copy the wallet in ten seconds. You can copy your wallet to compatible blank NFC cards bought locally. You need at least NTAG216-level memory capacity. Or order as many cards as you like for roughly $2–5 each and make ten backups if you want.

Stick a backup under your desk. Done. When did you last lose a desk?

Code recovery is enabled by default in Tangem: a second card from the same set can reset the first card’s password. You do not need to know the second card’s password to do this.

To stop a thief from getting both cards, you have to store them separately — for example, in different homes. In our view, this is an absurd chore for an ordinary owner: by our estimate, 90% of people cannot leave their cards in someone else’s home for safekeeping.

And if you hand a card to someone who has no contractual duty to safeguard it, they will lose it ten times faster than you would — and will not feel guilty about it.

If you keep two cards at home, you might as well consider them cards with no password at all. You do not need to know either card’s password. If you physically have both cards at home and recovery is enabled, you can reset the password at any time.

In that scenario, the fact that the private key cannot be extracted from the secure chip is meaningless — in practice and in theory. The key is effectively unprotected.

Tangem’s story goes like this: they took an existing security concept and layered their own business decisions on top. But borrowing a clever concept does not mean understanding it as well as the people who developed it. The additions were precisely what had to be revised after launch. It is like painting a hat on the Mona Lisa: nobody is questioning Leonardo’s painting — the problem is what you painted on top of it.

That is why the new version of Tangem introduced seed phrase imports and gave users the option to disable password resets using another card — a feature enabled by default.

Mitilena’s architecture has been linked to a developer from the traditional hardware-wallet ecosystem, the world of products such as Trezor. The system was designed from the start by a specialist who had spent years in the field and knew its problems and attack methods from the inside.

The Trust tier: protection from partners, authorities, and extortionists

The Mitilena ecosystem also offers its highest level of shared security — Mitilena Trust (based on Shamir’s Secret Sharing, available in the offline Air app).

The principle is simple: the seed phrase is mathematically split across several independent cards (for example, three or five). To send funds, you must present a majority of the cards — two out of three or three out of five, for example.

A single card does not contain the key: it cannot even reveal the wallet’s balance or address. This addresses the human factor: a dishonest director, an office partner, or a robber cannot take the money without assembling the required number of cardholders.

The editorial team considers the whole idea absurd: an ordinary personal crypto wallet should not force you to work out where to hide a second copy so that nobody can use it to reset your password.

If you have not disabled the default option to recover the access code using a second card, anyone in your household who gets hold of both cards can reset the code and spend your money.

What does a burglar look for when breaking into an apartment? What does a meticulous customs officer or law enforcement official look for when searching your luggage at the border? They look for recognizable signs of a crypto owner: Ledger boxes, distinctive Trezor devices, or Tangem cards with a logo screaming across the plastic. Finding one instantly makes you a target for questioning, extortion, or physical coercion to unlock it.

Mitilena Trust uses physical multisignature approval: a transfer requires cards from several participants. For example, company funds are split between three directors or accountants, and any two of the three can authorize a transfer. You give the other participant just one share of the shared key, rather than a spare card with full access to the money.

When it comes to robbers, even with a knife at your throat, your card alone is not enough to make a transfer. You also need another participant’s card, which you physically do not have. The same arrangement works for substantial family savings: different relatives hold different shares of the key.

If you are concerned about extortion targeting your personal savings, you can keep one of the required shares at a close relative’s home. You do not have to hand them a separate card that they must look after and remember where they put. You can place a sticker discreetly — for example, on the underside of a shelf inside a cabinet.

A sticker costs around $2, so you can make several copies of that share: one under a relative’s shelf, another in your father’s car, and a third under the seat of a bicycle kept in storage. If the cabinet is replaced or the bicycle is sold, the other copies remain.

Almost every hardware crypto wallet, including Tangem, practically screams, “I am a crypto wallet.” Mitilena’s cards and stickers are branded too. But a sticker is much harder to spot: it is a thin, coin-sized label that can be attached to all kinds of objects.

The key point is that a Mitilena wallet is not tied to branded hardware. Because the card serves as secure storage, you can buy a compatible blank NFC card with no printing — at least NTAG216 in terms of memory capacity — and write your wallet to it. A card like this costs around $3, and its appearance gives away nothing about its contents.

It can also be a fob with the same chip — something that looks like an ordinary parking or building-entry key. There is no wallet name, logo, or other clue that it holds access to cryptocurrency.

This is one of the most common crypto theft scenarios: you download an infected file or pick up a Trojan on a phishing site. The malware scans your computer for private keys — either in plain text or in files protected by weak passwords.

Both Tangem and Mitilena protect against this kind of search for keys in files: the private keys are stored on cards, so there is nothing for the malware to find on the computer’s drive.

These attacks are prepared for a specific person: you are already a significant target, and the attackers want to get to you in particular. Someone around you may point them your way and tell them about your money and habits.

This is a very expensive attack: the budget for a sophisticated zero-day operation starts in the hundreds of thousands of dollars. Such attacks are entirely real and are used in practice.

A Tangem card has no screen of its own. You enter the address and amount on your smartphone, which passes the transaction to the card for signing. An infected phone can show you “Send 100 USDT to Mom”, while sending the chip a transaction that transfers the entire $50,000 to a hacker’s wallet.

The chip dutifully signs the transaction. The key never left the card, and the cryptography worked perfectly — but the money went to criminals. This is blind signing. The chip’s protection works like a steering-wheel lock on a stolen car: the wheel is locked, but the car is simply loaded onto a tow truck.

Mitilena Air moves signing to a separate phone with no internet connection — and a screen of its own. The request is transferred via a QR code or an audio signal. On that phone’s screen, you check the recipient’s address and the amount, then tap your card. If your main smartphone replaced the payment details in the request, you will see the wrong address and refuse to sign. The completed, signed transaction goes back to the main phone to be broadcast to the network.

The Ledger Donjon lab publicly demonstrated a laser attack on Tangem: the researchers set a new password on the card without knowing the old one or having a second card. The card then allowed them to sign transfers. This is a published, reproduced laboratory result.

Mitilena has a protected storage mode that works with its own DESFire EV3 cards, certified to EAL5+. This mode is disabled by default. When enabled, it protects the data on two levels.

The first level is access to the storage on the card itself. Reading its contents requires getting past the card’s protection. The second level is the encrypted seed phrase inside. The app encrypts it before writing it to the card.

So even if a laser or another method bypasses the card’s access check, the seed phrase does not decrypt itself. What remains inside is ciphertext that still requires a password.

With Tangem, no separate decryption is needed after such a bypass: the card signs transactions itself. The attacker does not even need to extract the private key. A Mitilena card only stores encrypted data — permission to read it does not give anyone the ability to sign a transfer.

For someone to crack your wallet in this scenario, two conditions must come together in your life:

1. Someone must physically get hold of your card — take it from your pocket or desk — and copy the encrypted record from it.
2. Those people must have access to the computing power needed to brute-force that record. In our hypothetical example, that means a farm of one hundred powerful graphics cards.

In Mitilena, you can set a password in Russian or another language, using numbers and any emoji. Uppercase and lowercase letters are distinct. The maximum length is 12 visible characters. You can mix different alphabets and emoji in one password.

For every password guess, the software performs 100,000 iterations of computation — that is how PBKDF2-SHA256, used in Mitilena, works. This slows down every attempt.

Suppose the very same person who has access to your physical card somehow, by an incredible, almost fairy-tale coincidence, also has access to one hundred RTX 5090 graphics cards for illegal activity. As an everyday situation, this sounds absurd — but let’s suppose it happens.

For all one hundred RTX 5090s, let’s use a combined estimated speed of 10 million password checks per second. The estimate from the RTX 5090 benchmark is scaled to one hundred cards and 100,000 PBKDF2-SHA256 iterations, assuming ideal workload distribution.

• 12 random English letters and digits, including uppercase and lowercase letters: an average of more than 5 million years of brute-force searching.
• 12 random characters drawn from English and Russian letters and digits, again including both uppercase and lowercase: an average of more than 30 billion years.

And that is before adding emoji and other alphabets, which can also be used in the password.

Enable the protected DESFire format before writing the card, and even a simpler password holds up: the card itself throttles every attempt. At 30 ms per try, brute-forcing a random password of upper- and lowercase English letters and digits takes, on average, over a trillion years for 12 characters, and about 27 years for 6. The mode is supported by Mitilena’s branded blue cards and compatible unbranded DESFire EV3 cards.

Who guarantees there is no backdoor inside the chip? When a factory manufactures Tangem, it produces a recognizable crypto wallet. Assembly, packaging, a logistics warehouse, customs, courier delivery — at each stage, the product and its packaging can reveal that this is a device people will use to store thousands or millions of dollars.

In October 2026, the crypto market was rocked by a Ledger scandal: a hidden hardware module was found inside a wallet bought from CryptoBilis. According to Bitquery’s estimate, this seller’s customers lost more than $100 million. Then came reports of a suspicious Ledger bought at MediaMarkt — one of Europe’s largest and most trusted electronics chains. Not some shady stall, but a store where millions of people buy tech without a second thought. And that is only what has surfaced so far. The numbers are not final, and nobody knows where else these devices have ended up. We covered the details in our article about the Ledger hardware implant.

A Tangem card is sealed in plastic, and its firmware is closed. You cannot even inspect the circuit board without opening the card. Buyers are left trusting the manufacturer and trusting that the device passed through the entire supply chain without interference.

Mitilena takes a fundamentally different approach.

Here, the storage medium works like a safe: it does not generate wallet keys or sign transactions. It stores data you have already encrypted.

Mitilena uses mass-produced industrial NFC chips — NTAG216 and DESFire EV3. The same chip families are used for access passes, tickets, and other everyday purposes. The storage medium alone does not reveal that you intend to put a wallet on it.

Most importantly, the key is generated neither at someone else’s factory nor inside the card. The seed phrase is created on your own device — and, for the especially security-conscious, Mitilena Air can do this on a separate offline device with no internet connection. What gets written to the card is data encrypted with AES-256 using a unique random salt and your personal password.

Mitilena’s cryptography is built entirely on hugely popular open-source JS libraries. They power the banking apps, messengers and browsers of billions of people. They’re battle-tested.

Now the closed Tangem chip. Its code is written from scratch or assembled from a severely limited low-level programming toolkit used by 0.1% of all programmers. There are no billions of users filing bug reports, and no thousands of researchers either, because the code is locked away under NDA.

Google and Apple review every version of Mitilena before release. Don’t trust even them? Download the separate APK, take it apart with a disassembler and run it behind a firewall: you’ll see for yourself what it does and where it tries to connect.

In Mitilena Air, the seed phrase is created locally using the open BIP39 standard and the most widely used, battle-tested JS library, which draws entropy from your browser and throws an error if there isn’t enough, refusing to create a key. On top of that, Air lives on a separate phone with no internet, and on Android, network access is disabled right in the app’s permissions. Transactions travel via QR codes or sound. You can take Air’s APK apart yourself, too.