Abstract: A first device obtains a public key of a first home device and a first message leaving key that is used to encrypt an offline message between the first device and the first home device; obtains a public key of a second device and a second message leaving key that is used to encrypt an offline message between the first device and the second device; obtains a third message leaving key used to encrypt an offline message between the second device and the first home device; encrypts the public key of the second device and the third message leaving key by using the first message leaving key, to obtain first encrypted information, and requests a server to push the first encrypted information to the first home device; and encrypts the public key of the first home device and the third message leaving key by using the second message leaving key.

Abstract: Embodiments of the present disclosure provide a method for packet transmission and an electronic device. In an example method, an internet of things (IoT) device can generate a first internet protocol (IP) packet, where a destination address in a packet header of the first IP packet is an IP address of a central device instead of an IP address of a target device. The IoT device may encapsulate the IP address of the target device into a packet body of the first IP packet. In this way, the central device may determine, according to a firewall rule of the IoT device, whether to send the first IP packet to the target device, and the central device may be used as a firewall device.

Abstract: A first device obtains a public key of a first home device and a first message leaving key that is used to encrypt an offline message between the first device and the first home device; obtains a public key of a second device and a second message leaving key that is used to encrypt an offline message between the first device and the second device; obtains a third message leaving key used to encrypt an offline message between the second device and the first home device; encrypts the public key of the second device and the third message leaving key by using the first message leaving key, to obtain first encrypted information, and requests a server to push the first encrypted information to the first home device; and encrypts the public key of the first home device and the third message leaving key by using the second message leaving key.