Cryptnox BG1 Card🔍 Last analysed 29th April 2022 . Bad Interface
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Do your own research!
Try out searching for "lost bitcoins", "stole my money" or "scammers" together with the wallet's name, even if you think the wallet is generally trustworthy. For all the bigger wallets you will find accusations. Make sure you understand why they were made and if you are comfortable with the provider's reaction.
What is a bearer token?
Bearer tokens are meant to be passed on from one user to another similar to cash or a banking check. Unlike hardware wallets, this comes with an enormous "supply chain" risk if the token gets handed from user to user anonymously - all bearer past and present have plausible deniability if the funds move. We used to categorize bearer tokens as hardware wallets, but decided that they deserved an altogether different category. Generally, bearer tokens have these attributes:
- secure initial setup
- tamper evidence
- balance check without revealing private keys
- small size
- low unit price
- either of ...
- somebody has a backup and needs to be trusted
- nobody has a backup and funds are destroyed if the token is lost/damaged
The Analysis ¶
Cryptnox FIDO2 - FIDO2 Certified Level 1 Smartcard
- Cryptnox BG-1 Card Dual Seed Generation
- Two cards paired with a Mutual Authentication Security for Dual Generation
- Cryptnox BG-1 Card
- Crypto hardware wallet smartcard with advanced functionalities
- Cryptnox B-NFT-1 Card
- Specific card version with potential application to non-fungible token (NFT)
NFC and Contact Optional Fido2 Enabled Functionality (Choose Option)
Genuine check with On-Card Dynamic Active Authentication with Manufacturer Certificate Chain
- CloudHSM based (FIPS 140-2) Key Mangement Service and Secret Manager from Amazon Web Services Standard 12/24 Words (BIP 39)
- BIP32 & SLIP10 Key Derivation fully On-Card (no Parity Recovery needed) and Digital Signature
Export BIP32 XPUB Data
Digital Signatures : ECDSA “Koblitz Bitcoin” K1 and NIST P1 256 bits curves
Data Exchanges always fully protected within AES 256 bits Secure Tunnel, with MAC for integrity and authentication
Seed Generation from On-Card TRNG source
Card Authentication with:
- Windows Hello Biometrics (TPM)
- IOS with Biometrics (Secure Enclave)
- Yubikey Products with Personal Identity Verification Functionality ((NIST 800-73-4))
- File Encryption and Decryption (Encryption Key derived from Seed)
On-Card Transaction History and Counter Log
On-Card Blockchain Configuration Settings
Common Criteria EAL6+ Certified Chipset
Python3 CLI client for:
- Linux Ubuntu (including Ubuntu Core 20)
- IOS Application: https://apps.apple.com/app/id1583011693
Documentation has been provided by the project
- The Crypnox Software
- Cryptnox Py
- Cryptnox Card
- PyPi - Cryptnox Card
- PyPi - Cryptnox Py
- IOS App Store (Companion App)
- Snap Store (linux distributions)
- Compatible Third Party Software
How it works
Cryptnox gave this brief on how the device works:
Our Client Cryptnox wanted to make this entire process even safer by allowing the user to use a hardware wallet without having to work with the mnemonic phrase. They came up with an idea to offer users two separate cards, hardware wallets, which can generate the same private key inside of them without ever exposing it to the outside world.
This would allow users to use one card when they are making transactions and if that card gets stolen, or lost, they will have the backup, the other card which they have previously placed in a safe or some other secure place. As the cards are identical, the user can transfer the assets to another account from the backup card. Cryptnox needed somebody to help them implement their ideas in an innovative way — they approached HTEC Group to help them develop applications with a user-friendly interface that could perform a variety of advanced functionalities and turn their idea into a reality.
Solution We developed a complete iOS companion application that allows users to do transactions on Blockchain networks. The solution supports Bitcoin and Ethereum, and the user can, in CLI, use more granular commands, including working with smart contracts and the EOS network. At its core, it is a modern crypto wallet that uses our client’s cards for transaction signing.
The device noticeably has no display or means for the user to interact directly with the card. As mentioned above, the device needs the companion app:
“We developed a complete iOS companion application that allows users to do transactions on Blockchain networks”
Without a display, the user would not be able to approve transactions physically using the card. Transactions may be signed blindly.
The design of the device does not allow to verify what is being signed!
As part of our Methodology, we ask:Can the user verify and approve transactions on the device? If not, we tag it Bad Interface!
These are devices that might generate secure private key material, outside the reach of the provider but that do not have the means to let the user verify transactions on the device itself. This verdict includes screen-less smart cards or USB-dongles.
The wallet lacks either an output device such as a screen, an input device such as touch or physical buttons or both. In consequence, crucial elements of approving transactions is being delegated to other hardware such as a general purpose PC or phone which defeats the purpose of a hardware wallet.
Another consquence of a missing screen is that the user is faced with the dilemma of either not making a backup or having to pass the backup through an insecure device for display or storage.
The software of the device might be perfect but this device cannot be recommended due to this fundamental flaw.
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