Bitcoin transactions are secure, meaning they cannot be modified or stolen. This is because Bitcoin transactions are recorded on a blockchain, which is an immutable public ledger. The blockchain is maintained by a decentralized network of computers around the world, making it virtually impossible to tamper with or hijack the system.

Additionally, the cryptographic algorithms used by the blockchain to verify each transaction make it virtually impossible to hack or otherwise compromise the records on the blockchain. This ensures that Bitcoin transactions remain secure, and that users can trust that their funds will remain safe and secure.