Bitcoin's security comes down to one simple trick: thousands of separate computers all keep an identical copy of the same money ledger, so no single person or company controls it.

• Thousands of computers around the world each hold the exact same list of who owns what.
• When someone sends a payment, a new line gets added to that shared list.
• Miners check that each new line is valid, and they get paid in Bitcoin for doing that work.
• About every 10 minutes, the new lines get bundled into a new "page," called a block.
• Once a block is added, it can never be edited or erased — that permanence is why the system is called immutable.

Outlook: this decentralized, tamper-proof design is the core reason Bitcoin is marketed as harder to manipulate than money systems run by a single bank or government.