Recently, Zou and Qiu (Sci China Phys Mech Astron 57:1696–1702, 2014) proposed a three-step semi-quantum secure direct communication protocol allowing a classical participant who does not have a quantum register to securely send his/her secret message to a quantum participant. However, this study points out that an eavesdropper can use the double C-NOT attack to obtain the secret message. To solve this problem, a modification is proposed.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Statistical and Nonlinear Physics
- Theoretical Computer Science
- Signal Processing
- Modelling and Simulation
- Electrical and Electronic Engineering