Examples of electronic devices are described herein. In some examples, an electronic device includes an operating system. In some examples, the electronic device includes a processor. In some examples, the processor is to generate a first code. In some examples, the processor is to encrypt the first code based on a public key to produce a second code. In some examples, the processor is to enter a locked state, where a booting of the operating system is blocked in the locked state. In some examples, the locked state is unlockable with the first code. In some examples, the electronic device includes a communication device to output the second code. In some examples, the communication device is to receive an authentication message in response to the second code. In some examples, the processor is to enter an unlocked state based on the authentication message.