Denarium physical bitcoins
Denarium physical bitcoins, also called Denarium coins, are physical metal coins created by a Finnish Bitcoin company Prasos (Prasos Ltd, Jyväskylä, Finland) that contain an embedded piece of paper with digital Bitcoin value, covered by a tamper-resistant hologram. Denarium coins are available in different BTC increments. They can be purchased at Denarium's website, https://www.denarium.com (multiple payment methods accepted: Bitcoin, Visa, Mastercard, IBAN/SEPA bank transfer).
The coins are designed such that they could be circulated in face-to-face transactions. The first person to redeem its private key gets the value on the coin, and afterwards, the coin no longer has any Bitcoin value. It is difficult or impossible to read the private key on the coin without damaging or destroying the hologram, which exposes a honeycomb-like tamper-evidence pattern when peeled.
The piece of durable paper inside each coin has a private key which forms the backing for the Bitcoin value represented by the coin. Private key is in 30-character mini private key format. Redeeming the private key back into digital Bitcoins is currently available with a patched reference client as well as with many alternative clients.
Denarium coins are similar to Bitbills and Casascius physical bitcoins in that they are an object that contains a redemption code that serves as a bearer item for digital bitcoins.
There are 2 independent websites that track the status of all Denarium coins in circulation, based on information from the block chain:
- Denarium Bitcoin Analyzer (http://Denarium.uberbills.com/)
- Denarium Physical Bitcoins Database (http://Denarium.appspot.com/)
Releases of Denarium coins
Original series 1/10 BTC coin
- 2.86 cm / 1.126 inches in diameter
- Solid brass
- Year printed on coins: 2015
- Approximately 7.65 g / 0.269 ounces
- Denomination ("1/10 BTC") appears on the hologram
- Eight-digit "firstbits" visible through a small transparent window that allows limited visibility of one side of the private key paper
- First appeared in June 2015 [1].
- Private key: both 30 character string inside the coin and a QR-code, the 256-bit private key is SHA256(string)
- All 4,000 Bitcoin addresses pre-generated for the series have been published on GitHub as automatically updating Bitcoin-signed list
Original series 1/100 BTC coin
- 2.86 cm / 1.126 inches in diameter
- Solid brass
- Year printed on coins: 2015
- Approximately 7.65 g / 0.269 ounces
- Denomination ("1/10 BTC") appears on the hologram
- Eight-digit "firstbits" visible through a small transparent window that allows limited visibility of one side of the private key paper
- First appeared in June 2015 [2].
- Private key: both 30 character string inside the coin and a QR-code, the 256-bit private key is SHA256(string)