1 Implementation of Mobile Banking Authentication System Using RC5 Encryption Algorithm Moe Pwint Phyu, Dr. Win Win Thant University of Computer Studies, Yangon (UCSY) mmpwint7@gmail.com,winwinthant@gmail.com ABSTRACT Nowadays, Mobile Banking (MB) System is performing of finance related functions on a mobile device. MB can be used anywhere you take your device and fast banking today. Current MB confidentiality and authentication are challenging and then identified as major security risks. In this paper, MB system is implemented on confidentiality, authentication and verification of security channels to protect the system’s security risks. To protect the confidentiality and authentication, RC5 encryption algorithm is used to encrypt PIN (Personal Identification Number) number in MB system. Then, CAPTCHA image grid view is used to protect the verification. Therefore, this system can fulfill not only the requirement of the security of mobile user but also the security of banking database system. Keywords: Mobile Banking System, Rivest Cipher 5(RC5), CAPTCHA Image 1. INTRODUCTION Mobile banking is a revolution that is driven by the world’s one of the fastest growing sectors mobile communication technology. Data at the user end with mobile device is not only sensitive but also the data of database at the MB server end is sensitive. A very key component of protecting information confidentiality would be encryption. Encryption ensures that only the right people can read the information. Encryption is very widespread in today’s MB system and can be found in almost every major protocol in use. Therefore, in this paper, secure MB authentication system has been configured by using RC5 encryption algorithm and CAPTCHA images grid view. Firstly, PIN number of mobile user is encrypted by using RC5 encryption algorithm for authentication and confidentiality security goals in system. Secondly, CAPTCHA image is used for extra security or verification in system. Encryption of PIN number and CAPTCHA image are used for identified the uniqueness of authorized person. There will mainly protect that risk of unauthorized persons using the mobile phone for MB. The MB application is very useful for more secure the user end and bank end. It can also save the time of mobile users. Moreover, mobile users can safely access that their banking activities from anywhere. Due to the obvious security advantages of mobile banking application, now the system has gained great popularity in more places. The rest of the paper is organized as follows. Related works of the system are described in section 2. Section 3 explains the background theory. The design and implementation of the proposed system are presented in section 4. Section 5 contains scope and limitation of the system and section 6 describes conclusion of the system. Finally, section 7 presents future work to further improve our MB system. 2. RELATED WORK There have been numerous studies that associated with banking system and the use of