In this paper, polar codes recently presented by Arikan are introduced. Polar codes have a number of channels with high capacity where information is located. In addition, these codes are composed of a number of channels with low capacity called frozen bits. In the first proposed design, the authors optimally use frozen and useless bits of the polar code and insert the encryption key on all the bits of the design (information bits and frozen bits). In fact, in Arkian’s proposed 8-bit design, they use 8 encryption keys. Then, in the rest of the paper, a method is presented through which the number of encryption keys applied can be reduced.