These bitcoin banknotes were sold by Tangem company and are rather calledāsmart-banknotesā. They are not really made of paper; they are hardware storage units with a S3D350A chip manufactured by Samsung. What they have in common with banknotes is that they represent one set value and can be physically given as payment at an outlet. In essence, these notes are self-contained wallets with their own private key. Tangem refers to them as āuncopiable cold wallet[s]ā.
According to a Tangem, the chip technology is tamper-proof, addressing āall known attack vectors on hardware and software levels.ā It says that years of chip development via credit cards, SIM cards, and ID cards have led to a product secure enough that ācost of hacking a single banknote [is] uneconomicalā.
The notes have an advantage over online transactions because payment is instant and does not incur a fee. The disadvantages to be fixed are security, distance, and convenience.
Banknotes are available for purchase now in denominations of 0.01 and 0.05 BTC
