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BitSafeCard

🔍 Last analysed 2nd February 2023 . Leaks Keys
28th December 2021

This product requires sharing private key material!

As part of our Methodology, we ask:

Leaks Keys!

Does the device hide your keys from other devices?

If the answer is "no", we mark it as "Leaks Keys".

Some people claim their paper wallet is a hardware wallet. Others use RFID chips with the private keys on them. A very crucial drawback of those systems is that in order to send a transaction, the private key has to be brought onto a different system that doesn’t necessarily share all the desired aspects of a hardware wallet.

Paper wallets need to be printed, exposing the keys to the PC and the printer even before sending funds to it.

Simple RFID based devices can’t sign transactions - they share the keys with whoever asked to use them for whatever they please.

There are even products that are perfectly capable of working in an air-gapped fashion but they still expose the keys to connected devices.

This verdict is reserved for key leakage under normal operation and does not apply to devices where a hack is known to be possible with special hardware.

The product cannot be independently verified. If the provider puts your funds at risk on purpose or by accident, you will probably not know about the issue before people start losing money. If the provider is more criminally inclined he might have collected all the backups of all the wallets, ready to be emptied at the press of a button. The product might have a formidable track record but out of distress or change in management turns out to be evil from some point on, with nobody outside ever knowing before it is too late.

Help spread awareness for build reproducibility

Please help us spread the word discussing build reproducibility with BitSafeCard  via their Twitter!

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.

If you find something we should include, you can create an issue or edit this analysis yourself and create a merge request for your changes.

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 require these attributes:

  • Secure initial setup
  • Tamper evidence
  • Balance check without revealing private keys
  • Small size
  • Low unit price
and either of these applies:
  • Somebody has a backup and needs to be trusted.
  • Nobody has a backup and funds are destroyed if the token is lost or damaged.

The Analysis 

Product Description

The website for the product is written primarily in Turkish so some details are not very clear to us.

For instance, in its Introduction Page:

Hersey bukadar kolay. Kartınızın üzerindeki adrese kriptolarınızı gönderin, kartınızın arkasındaki anahtarla transfer yapın.

Translated:

Everything is that easy. Send your crypto to the address on your card, transfer with the key on the back of your card.

It was not clarified what sealing method was used to cover the QR code or the plaintext private key

In its tutorial page on transferring bitcoin using Blockchain.com wallet:

It was described that the private key has to be imported by scanning the QR code at the back of the card.

Bitcoin - Bitcoin Cash - Ethereum - Stellar arasından seçiminizi yapın (Bitcoin soğuk cüzdanı kullanıyorsanız “Bitcoin” seçin) Sağ taraftaki “Import Address” butonuna tıklayın.

“Enter your private key” bölümüne BITSAFECARD para çekme bölümündeki şifrenizi ya da QR kodunuzu okutun. Böylece kartınızdaki tüm kriptoparanız Blockchain.com ‘da oluşturduğunuz elektronik cüzdana geçiş yapacaktır.

Translated:

Choose between Bitcoin - Bitcoin Cash - Ethereum - Stellar (choose “Bitcoin” if you are using a Bitcoin cold wallet) Click the “Import Address” button on the right.

In the “Enter your private key” section, read your password or QR code in the BITSAFECARD withdrawal section. Thus, all your cryptocurrency on your card will be transferred to the electronic wallet you created on Blockchain.com.

Analysis

We tried to confirm whether the private key QR code is indeed sealed by tweeting them.

Even if it were sealed like in other tokens such as Casascius, no other special process has been detailed in the website. No mention of encrypted passphrases or any of the sort was detailed.

If we are correct, this exposes the private key in its QR form. Guarantees that the manufacturer is also not making copies is also insufficient and should be subject to greater scrutiny by buyers.

(dg)