Abstract：Security is a critical concern that must be addressed in the context of the electric power metering

internet of things（IoT）. In order to achieve complete isolation between data stored in the public cloud（external

network）and data stored in the private cloud（internal network），while enabling unidirectional communication

from the external network to the internal network，a non-electric communication method based on encrypted QR

codes was proposed. The method involved the generation of colored QR codes containing metering inspection

information on the external network side. Data from the external network was transmitted unidirectionally to the

internal network via these colored QR codes，with no electrical connection between the internal and external

networks. To enhance security，a color/information hybrid encryption method was employed. The original

inspection information was encrypted using the SM4 algorithm to generate monochrome QR codes. Subsequently，

the monochrome QR codes were further encrypted using different colors by DNA and chaos，leveraging the rich

color gamut of the display monitor. Experimental results demonstrate 100% accuracy in encryption and decryption，

encryption and decryption computational speeds of less than 0.058 7 s，and linearly increasing time consumption.

This method exhibits high accuracy and speed，meeting the requirements of electric power metering IoT systems in

terms of transmission rate，security and reliability.

      Key words：power measurement；internet of things（IoT）；two-dimensional code；encryption；non-electronic communication