Quote from: Kakmakr on May 15, 2018, 05:48:42 AM

Quote from: odolvlobo on May 15, 2018, 05:10:23 AM

Quote from: Carlton Banks on May 14, 2018, 09:17:40 PM

Quote from: infofarmer on May 14, 2018, 01:55:17 PM

Only the chip creates and controls the private key, it's impossible to export or import the key. The firmware is audited and the chip is highly certified.

So the blockchain address is accessible, but the private key is not?

If so, there's a flaw in your model, and you've misunderstood how cryptographic keypairs work. There's no way for anyone holding a Tangem Bitcoin note to prove that they own the money at the respective Bitcoin address on each note.

How can you prove that the money at these addresses is money sent to the address by Tangem, and not just any random bitcoin blockchain address with 0.01 BTC contained? How can people be sure Tangem didn't use the same address twice, three, four or a hundred times on different notes? Are you going to release videos of Tangem workers sending each transaction to every Tangem note ever made? Will that be enough for people to trust the funds are really unspendable by Tangem, or that you aren't re-using addresses over multiple notes?

I have found no information on how they are supposed to work. My guess is that the chip will cryptographically verify its authenticity and it represents some amount of BTC held by Tangem. That would not be very appealing to me but I guess we'll just have to wait and see.

If I understand this correctly, the chip within the card can be read by a mobile phone and the mobile phone is connected to their APP which links to the Blockchain. So you are not accessing the companies own ledger, with some tokens linked to the card. You have access to the coins that are linked to the Blockchain.
You need a phone with NFC enabled to access the information on the card.

The site recently added more information, including this:

Quote

The value can be extracted at any time by signing a transaction from the Tangem Note to an arbitrary Bitcoin wallet. This requires a compatible NFCenabled Android phone and is protected by a 60to120second security delay. Faraday wallets recommended for additional security.

Private keys cannot be imported or exported from Tangem Notes under any circumstance. No backup possible by design. Each Tangem Note creates its own private keys and can never disclose them. The value is completely tied to the physical chip. Loss, theft, or destruction of a Tangem Note will result in loss of funds.

It looks like the chip will sign transactions, so it is like a hardware wallet.