Bitcoin Is Open Source
Many in the crypto community aren’t actually aware that Bitcoin is actually an open source software. What open source means is all the code is able to be viewed online (if you don’t believe me head on over to https://github.com/bitcoin/bitcoin). There you can see the nuts and bolts of Bitcoin and who is working on it. If you had the requisite knowledge, you could volunteer to assist the Bitcoin core team and actually work on Bitcoin yourself. Furthermore, you could ‘fork’ the Bitcoin code and create your own cryptocurrency based on Bitcoin. What isn’t open source is the cryptography behind bitcoin, which is what keeps it secure from malicious attacks.
Peer to Peer
Bitcoin is built as a peer to peer (p2p) software. This is what allows Bitcoin to be decentralised at its core. In a banking system, the bank has a ledger that stores your currency total. When someone wants to send you money, they are making that transaction with the bank as the central authority. Using Bitcoin, the transaction is sent through a peer to peer network of nodes that verify transactions. Think of this like a monetary version of bittorrent, napster or any other peer to peer file sharing service. The difference here though is the blockchain.