Blockchain Vocabulary - Double Spend (14/30)

Predecessors to Bitcoin were not able to solve a core challenge for a decentralized digital monetary system: ensuring the same digital money was not spent twice.

The same PDF can be copied a thousand times and sent to a thousand different people because it is digital. Ensuring there is only one digital copy of something and it can only be owned by one person at a time without involving layers of banks and brokers is more difficult than it may seem.

Bitcoin protects against double spending in two main ways:

• If there are multiple unconfirmed transactions related to the same Bitcoin, whichever transaction gets the maximum number of network confirmations will be included in the blockchain, while others are discarded.
• Confirmations and transactions are time-stamped after they are confirmed so the record becomes immutable.

This seemingly simple innovation has opened the floodgates for all types of use cases that were not possible before without involving centralized authenticators of transactions to prevent double spending.