May 12, 2016

Physical Bitcoins

Physical Bitcoin is a special type of Bitcoin wallet that works as a bearer instrument that can be used to store bitcoins more safely or for trade offline.

A physical bitcoin holds the coin’s public address and a hidden private key. The intention with a physical bitcoin is that the value of the coin has not and cannot be spent as long as the private key remains hidden, which is likely achieved through the use of a tamper-evident seal.

The earliest physical bitcoin, the Bitbill, was shaped liked a credit card but that was then followed by the Casascius physical bitcoin which was affixed to a round medal. As of Nov 27, 2013, Casascius has suspended sales of items that contain digital bitcoins due to the strict regulation of United States. Since then, there have been several new coin manufacturers, and one of them is Denarium Bitcoin. PrintCoins is creating cheques and denominated bills.


Spending bitcoins from paperwallet or other cold storage

This article guides you through importing bitcoins from any paperwallet or other cold storage wallets like denarium bitcoin wallet. You can use mobile, web or desktop wallet in the process. Any wallet that offers the possibility “import private key” can be used for this process. At the end of the article, we have details about several wallet options which use can use.

Only import bitcoin once from denarium bitcoin wallet or paperwallet.

You can add funds to your paperwallet or other physical wallets as many times as you like. When importing the bitcoin, you should do it all at once as a safety protocol. When you import your private key to the mobile wallet or computer your paperwallets security will be compromised. In most cases, information about your private key will exist in the device where you imported it.

Mycelium mobile wallet offers fairly safe possibility for partial spending. Mycelium automatically deletes information about the private key from your phone shortly after the import. This means that your private key can be stolen only if your phone is hacked when you do the import.

Most convenient method for importing funds is using private key QR-code. These instructions focus on this option. Some wallets support only imports with the private key in text format. Typing your private key requires little effort. If you misspell something, you don’t need to worry about losing your funds as with misspelling a bitcoin address where you are sending bitcoin. You just won’t be able to withdraw the funds until you type your private key correct.

Here are some trusted wallets we have tested.

NamePlatformPrivate keyMini private keyBIP38HD Wallet
Blockchain.infoWeb walletYesYesYes?
Bitaddress.orgWeb walletYesYesYesNo
denarium mini private key

Denarium coins use mini private key

Security wallet BIP38

Paperwallet with BIP38 private key



Step by step guide to spending bitcoin from cold storage to web wallet

Using web wallet for spending cold storage bitcoin requires decent web camera from your computer. We recommend using Firefox or Opera as a web browser for the process. Other browsers may not work or require extra effort.

Go to Settings
-> Addresses

-> Import Bitcoin Address

Scan the private key QR-code from your cold storage. After scanning the QR-code choose “transfer” and your funds from the paperwallet transfer to your blockchain wallet.

You can import regular private keys and mini private keys to wallet with the same process. If your wallet is BIP38 encrypted asks you to type your passphrase to complete the transfer.

Step by step guide to spending bitcoin from cold storage to mobile wallet

This guide will walk you through importing your funds to Breadwallet mobile wallet. Breadwallet is mobile wallet which functions on Android and iOS devices. It supports both private key and mini private key QR- codes. Breadwallet doesn’t support importing from wallets that are BIP38 encrypted.

Open your Breadwallet app from your phone

-> go to settings

-> import wallet

-> scan private key

After scanning Breadwallet shows the available funds in your cold storage and asks you to confirm the transaction. Press “confirm” and the funds will be imported.

Breadwallet import private key


Partial spending using Mycelium mobile wallet

Mycelium gives you probably the safest option for spending only chosen amount from your cold storage. Your private key will be stored on your phone only temporarily. When importing funds to Mycelium, you can choose options “use all funds” which withdraws all funds from your wallet. To import only part of your bitcoin you can type the amount you wish to import.

Choose “Cold Storage” from your Mycelium wallet. Scan your cold storage wallet private keys QR- code. Import chosen amount of bitcoins. Unfortunately, Apple iOS version of the Mycelium doesn’t support mini private keys at the moment so importing from Denarium bitcoin wallet is not possible.

Mycelium Bitcoin cold storage spending


Spending bitcoin from cold storage to desktop wallet

Wallet options for transferring cold storage funds to desktop wallet:


Electrum doesn’t support scanning QR-code with Mac or Windows.

Importing to Electrum wallet:

Open “wallet” menu. “Enter private keys” window opens up.

Electrum private key import

Keep the shown receiving address unchanged. Type here your private key to sweep all funds from your cold storage.











Electrum private key import

Choose “Broadcast” to complete the import.