علي عامري مهر

The quantum secure ‎communication based on single photons is studied in this thesis. In particular, the security of a quantum secure direct communication equipped with authentication is analyzed, and an impersonation attack against it is given. Then, an improved protocol with higher security, lower-cost implementation, and wider applications is proposed. Afterwards, a quantum symmetric cryptosystem is presented. The cryptosystem, which in used algebraic error-correcting codes instead of quantum ones, can be utilized in the off-line systems such as quantum e-mails.