Main functions of Bitcoin’s monetary system

In order to provide a functioning monetary system, without a central mediator, Bitcoin needs to achieve the following:

1. Maintaining an accurate historic ledger of transactions & unspent balances
2. Validate new transactions that confirm with the rules (consensus mechanism)
3. Add those transactions to the historic ledger, in the correct date order & data format
4. Issue new bitcoin at the defined rate – currently 6.25BTC per new block
5. Allow wallets to spend & receive transactions & sync to the ledger
6. Act as a service for external users/services to reference transactional data
7. Route information across participants in its peer-to-peer network

Satoshi Nakamoto encapsulated these functions in the original reference code he wrote in 2008.  It has since been updated and is made available in a reference client, the most commonly used being Bitcoin Core.