Voice and image encryption, and, performance analysis of counter mode advanced encryption standard for wimax

This thesis deals with the implementation of the Advanced Encryption Standard's (AES) counter mode (CTR/ CM) as a standalone engine for securing voice and image data. This implementation can be easily adapted to the latest fourth generation (4G) wireless broadband technologies like WiMAX, with improved performance. Data, when transmitted through a noisy communication channel, is adversely affected by it resulting in errors. Forward error correcting codes are conventionally employed to correct these errors. However, when data that is encrypted using a secret key algorithm is transmitted through such noise however, the errors increase exponentially. Forward error correction proves to be a futile endeavor to correct such errors and new techniques are needed to correct these errors. The approach in this thesis is twofold, first to use the counter mode to encrypt audio and image data, to show the feasibility of implementation and, then to arrive at a new technique to improve performance of encrypted data in the presence of noise. A Bose, Chauduri and Hocquenheim (BCH) code is then used in conjunction with this new method to reduce the overall Bit Error Rate (BER) compared to those techniques which use standard error correction procedures only.