A New Solution for Password Key Transferring in Steganography Methods by CAPTCHA through MMS Technology

The Multimedia Messaging System (MMS) allows a user of a mobile phone to send messages containing multimedia objects, such as images, audio or video clips. On the other hand establishing hidden communication is an important subject of discussion that has gained increasing importance nowadays with the development of the Internet. One of the methods introduced for establishing hidden communication is steganography. Therefore steganography in MMS is an interesting idea. One of the problems in steganography methods is the security of transferring password key used for steganography between sender and receiver of secure data. In this paper a new method is proposed for solving this problem using CAPTCHA method through MMS messages. In this method the password key is spoken in an audio file and the data are hidden in the image by this password key. Then the image and audio files are inserted in a MMS message and sent to the receiver. Therefore the human receiver can recognize the password from the audio file and extract the data from the image using this password, but the computer cannot recognize the spoken word from the audio file and extracting the password. By this method the user does not need to memorize any password for extracting the data. This method has been implemented in J2ME programming language.