In: Computer Science
If bitcoins were sent to a certain address, why only its owner can use them?
Bitcoin address is a string of letter and numbers that represents a Bitcoin destination on the network.
Why only owner can use them?
Bitcoin addresses are used only when receiving bitcoins and are not ever re used. Receiver generate a single, unique address for each transaction to provide it to the sender. Reciver can generate a one time unique address using their wallet app and provide it to the sender. Sender now plus this address into their bitcoin wallet app. It is better to cop paste the address as it is to avoid any human error and transaction is done
Note: There is no harm or risk in receiver sharing their address with the sender as it won't contan any sensitive information. As, the address are always generated newly and are used only once
So, even if it is sent to a network address it won't be used by anyone else apart from it's owner as the address is new and is only known the receiver. If your phone is lost or data is stolen somehow, the next transaction will again involve generating of a new address and old address can no longer be used to compromise or steal bitcoins