Public key cryptography is great. By handing people a public key they can encrypt message that only you, the holder of the private key, can decrypt. However, there is one consideration that should be obvious. The private key must remain private. Once put publish your private key for others to see anybody can decrypt messages encrypted with your public key. Sometimes the consequences of such a breach are minor but sometimes they result in money being stolen:
On Friday, Miller learned an important lesson. It was an experience that everyone should remember before they start moving their money into the digital currency.
While on air, Miller surprised Bloomberg anchors Adam Johnson and Trish Regan each with $20 worth of Bitcoin.
But as Johnson received the paper gift, he briefly exposed the QR code (see above). This act was effectively like sharing a bank account and PIN number.
Immediately, someone lifted the QR code and stole the $20.
Bitcoin utilizes public key cryptography. Public keys allow other people to send money to other users. Private keys allow people to withdraw Bitcoin from a wallet. If somebody else nabs your Bitcoin private key they have full access to your funds. So don’t do something stupid like hand your private key to somebody else or who it on television.