The Design And Implementation Of SMS Encryption System Based On Point-to-point

With the rapid development of communication technology,the short message service attracted people's attention.People often use short messages to communicate in business and life,for example,many merchants use short messages to deliver some business secrets,users send their own important personal information by short messages,such as bank cards and passwords.On the one hand,the short message service brings convenience to people's daily life and improve efficiency.On the other hand,it also brings the corresponding security issue.Attackers can intercept and tamper with short messages by monitoring the SMS database.Therefore,how to guarantee the safety of short messages has become a problem that need to be solved in the project.In this paper,SMS based on Android point-to-point encryption system has been designed and implemented in order to solve the problem of security in the process of sending SMS.This paper mainly completed the following work:(1)To circumvent the server use and avoid the risk of a third party to communicate,the software uses technology called the communication of point-to-point,that is to say SMS plaintext and ciphertext is dealed with in SMS sender and receiver.(2)In order to ensure the safety of message transmission,message encryption communication process was designed and developed.The encryption process is relatively complicated,the software divided into multiple stages,negotiation key phase,encryption and decryption process processing,periodic public key and so on.a)In the negotiation key phase,the main task is to obtain both the public key and complete the preservation of its related information.b)Encryption and decryption process is divided into the first processing and subsequent processing.In the first process,this paper mainly adopts RSA + AES algorithm to deal with the clear text and ciphertext.Subsequent processing mainly uses AES algorithm,which improves the efficiency of encryption and decryption.c)To solve multiple cycle communication,this paper uses the communication cycle to guarantee the safety.(3)The characters of sending a short message are limited,so multiple sets of distribution is used to solve the problem that the stitching ciphertext is too long..In addition,to solve the problem of losing ciphtertext caused by line or signal problem,retransmission mechanism and checksum methods are used in this system.(4)Taking into account the practicality and the robustness,the software increases some features such as the contact book,pattern password lock settings to improve the availability and effectiveness.Design ideas of the software system are analyzed in detail in this paper,the relevant code realization and optimization work are completed,finally it is used in practical.