Date on Master's Thesis/Doctoral Dissertation


Document Type

Master's Thesis

Degree Name

M. Eng.


Computer Engineering and Computer Science

Committee Chair

Imam, Ibrahim Najati


Cell phone systems--Security measures


Electronic communication is gradually becoming a larger part of today's society. This type of communication not only encompasses ways people stay in touch, but also how people manage or share their personal data. As this type of communication increases, the protecting of sensitive data becomes a goal amongst users. The goal of this thesis is to offer a secure solution for mobile devices to share data with other mobile devices. The idea is simple: provide a software solution that can be ported to multiple mobile device platforms that will allow a user to securely encrypt a message that can be sent using existing communication technologies from one mobile device to another, where that encrypted message can then be decrypted and used by the recipient. The method should rely on a common passkey that the sender and recipient agree upon through verbal communication in advance that can be used to encrypt and decrypt messages that are transmitted between them. The passkey should also never be documented (in the application or elsewhere) to prevent it from being discovered by an attacker. Although it would be possible to write this application on different platforms, the result is an application that is used on Apple's iPhone. The application uses the secure open-source Blowfish cipher. A sender can type in their plain-text message and a passkey. The application can then encrypt the plain-text message and output a cipher-text message that the sender can then copy and paste into a text message or email. The recipient can copy the ciphertext into the application"s message field along with the shared passkey and then decrypt the message into its original plain-text format. This method offers the best flexibility, by taking advantage of technologies that mobile device customers use frequently, and a solid secure method of protecting their messages by way of the Blowfish cipher algorithm. The application presented in this thesis offers a way to enable secure messaging with mobile devices. With that being said, this application is not meant to be the final answer to this problem, especially since the current iteration has not been ported to other platforms. The application could also be modified to offer better support in the transmission of these messages as well to offer a better experience to the end user. With this introductory application, it is hoped that security in digital communications will be brought under the speculation of its users so that more secure options will become available.