Bitcoins are a virtual form of money protected by unbreakable cryptography. This attribute makes it a secure way to store wealth but also creates the risk that when Bitcoin owners die, their digital fortune will be out of reach forever.
Bitcoins are stored in a virtual wallet. Each wallet uses a string of random characters called a public key, visible to anyone, as an address for sending and receiving the cryptocurrency. A separate private key allows the owner access to the wallets contents.
If a Bitcoin owner dies without passing on the private key, his heirs may discover his wallet only to realize that they will never gain access to the wealth inside. To prevent this, the owner simply has to ensure that someone gets a copy of the private key by writing it down, storing it on a flash memory drive, or entrusting it with a commercial service that manages them.