Abstract:Data Encryption Standard(DES) algorithm is a typical private password mechanism,and its group is symmetric. The algorithm is very important in the field of encryption study. It is adaptive to the applications for encryption in many different systems, especially in the embedded system of Internet of Things(IOT) and Convergence Networks in the next generation. This article simply introduces the principle and the safety of DES algorithm. According to the characteristics of the DES algorithm,an improved scheme is put forward in order to overcome its easily attacked shortcomings. This method adopts two keys to crosswise encrypt. It can improve the complexity of encryption key in the process and enhance the ability of resisting attack, therefore, the safety of DES algorithm is improved.