Cryptnox
Cryptnox is a Swiss maker of NFC smart cards whose hardware wallet is a screenless two-card set: the second card is the backup, and transactions are reviewed in the app.
What Is Cryptnox?
Cryptnox is a Swiss maker of NFC smart cards, registered in Carouge in the canton of Geneva. Besides authentication cards and card readers, it sells one crypto product: the Cryptnox Hardware Wallet, a set of two cards built on an NXP secure element.
The cards have no screen, battery or buttons. A card is tapped against a phone or used with a smart-card reader on a desktop. The transaction is prepared and reviewed in the Cryptnox app, and the card signs what the app sends to it.
By default the two cards generate the same seed between themselves. The seed cannot be exported and no recovery words exist, so the second card is the backup, and losing both cards means losing access. As an alternative, an existing 12- or 24-word BIP39 phrase can be imported, which keeps a standard written backup.
The central trade-off is the missing screen. Recipient and amount can be checked only on the phone or computer, and if that device is compromised the card cannot show the real details. The card applet and the mobile app are closed source, while the command-line tool and SDKs are open. Cryptnox says Cure53 audited the applet in 2019, but the report is not public. Solana and other ed25519 chains are not supported.
NFC Connectivity in cryptocurrency enables contactless transactions using near-field communication, allowing users to sign or authorize actions by tapping their device to a reader.
Read full definition: NFC ConnectivityA secure element is a tamper-resistant chip built to store secrets and resist physical attacks such as side-channel analysis and fault injection.
Read full definition: Secure ElementRecovery is the process of restoring access to a cryptocurrency wallet using its seed phrase or mnemonic backup if the original wallet is lost or inaccessible.
Read full definition: RecoveryA backup in cryptocurrency is a secure copy of a wallet's seed phrase or private keys. It enables recovery of funds if the original wallet is lost or damaged.
Read full definition: BackupBIP39 is a standard for generating mnemonic seed phrases that are used to create deterministic wallets and securely back up cryptocurrency private keys.
Read full definition: BIP39Solana is a high-performance layer-1 blockchain platform that enables fast, low-cost transactions using Proof of History and Proof of Stake. Its native token is SOL.
Read full definition: SolanaReal-World Examples
Example 1: A user sets up the Cryptnox Hardware Wallet so that both cards hold the same seed, carries one and keeps the other in a bank deposit box. When the first card is lost, the second still signs.
Example 2: Malware on a phone replaces the recipient address before the transaction reaches the card. The card signs what it receives, and there is no screen on it where the change could be noticed.
Example 3: Someone who prefers a written backup imports an existing 24-word BIP39 phrase into the card and keeps the words on paper.
Malware is malicious software that steals or redirects crypto, for example by logging keystrokes, swapping copied addresses or reading wallet files.
Read full definition: MalwareA backup in cryptocurrency is a secure copy of a wallet's seed phrase or private keys. It enables recovery of funds if the original wallet is lost or damaged.
Read full definition: BackupBIP39 is a standard for generating mnemonic seed phrases that are used to create deterministic wallets and securely back up cryptocurrency private keys.
Read full definition: BIP39Cryptnox hardware wallets
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Frequently Asked Questions
What happens if I lose one of the two Cryptnox cards?
By default both cards hold the same seed, so the second card is the backup and still signs. The seed cannot be exported and no recovery words exist in that setup, so losing both cards means losing access. Keeping the cards in separate places reduces that risk.
Can I keep a written recovery phrase with Cryptnox?
Yes. As an alternative to the default two-card setup, an existing 12- or 24-word BIP39 phrase can be imported into the card. That keeps a standard written backup, which you then have to store and protect yourself.
How do I verify the recipient address if the card has no screen?
Only on the phone or computer, because the card has no display. The card signs what the app sends to it, so if that device is compromised and the recipient is changed, the card cannot show the real details. The check is only as reliable as the phone or computer.
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