Cellular phone or the so-called cell phone is now the primary means of communication for most people. Moreover, the phone has the facility of short messages service (SMS), which has cheaper rate than voice communication via cell phone. But unfortunately the default SMS facility from most cell phones still do not have adequate safety features, it is because messages are sent and received in the form of plaintext which can be easily read by anyone. Therefore in this thesis are discussed about the design of an application program that aims to encrypt and decrypt messages using the Vigenere algorithm. The end result of this thesis is an application program for mobile phones. These applications can run on phones minimal Android version 2.2 (froyo). This application will generate a random message which difficult to translate without the appropriate key.