“verify, don’t trust” principle is what gives Bitcoin its security and resilience. The network’s integrity doesn’t depend on who sends the data, only on whether the data follows the rules.

When a Bitcoin node receives a transaction, it: 1. Receives it from another node. 2. Verifies that it’s valid. 3. Stores it in the mempool if valid. 4. Propagates it to other nodes. 5. If it’s a mining node, it may include the transaction in a new block.