Problem in encrypting an audio file in matlab

m encrypting an audio file in matlab successfully execute , but it is taking 16 values every time , as audio file has huge values when i divide audio file size with 16 it is giving me 689 .....means at every rotation it will return a cipher text n total cipher texts at the are 689 ...i m confused that how to embedd a bundle of cipher texts in any image...how much bits i need to embedd these cipher text .....or is there anyother way for encryption so that cipher text may decrease....??

my demo file

%AES_DEMO Demonstration of AES-components.

%

% AES_DEMO

% runs a demonstration of all components of

% the Advanced Encryption Standard (AES) toolbox. %

% In the initialization step the S-boxes, the round constants,

% and the polynomial matrices are created and

% an example cipher key is expanded into

% the round key schedule.

% Step two and three finally convert

% an example plaintext to ciphertext and back to plaintext.

% Copyright 2001-2005, J. J. Buchholz, Hochschule Bremen, [e-mail]

% Version 1.0 30.05.2001

% Initialization [s_box, inv_s_box, w, poly_mat, inv_poly_mat] = aes_init;

% Define an arbitrary series of 16 plaintext bytes

% in hexadecimal (string) representation

% The following two specific plaintexts are used as examples

% in the AES-Specification (draft)

% plaintext_hex = {'00' '11' '22' '33' '44' '55' '66' '77' ...

% '88' '99' 'aa' 'bb' 'cc' 'dd' 'ee' 'ff'};

%plaintext_hex = {'32' '43' 'f6' 'a8' '88' '5a' '30' '8d' ...

% '31' '31' '98' 'a2' 'e0' '37' '07' '34'};

% % x = fopen('D:\MATLAB\AES\Aa.txt', 'r');

% %

% %

% a = a(1:16);

% size(a);

[plaintext1,fs]= wavread('A1.wav','native');

plaintext1=plaintext1(1:16);

plaintext_hex=dec2hex(plaintext1);

plaintext = hex2dec (plaintext_hex);

plain =[];

for i = 1:11025

plain[i]=plaintext1(1:16);

end size= length(plain);

% Convert plaintext from hexadecimal (string) to decimal representation

% This is the real McCoy.

% Convert the plaintext to ciphertext,

% using the expanded key, the S-box, and the polynomial transformation matrix

for i = 1:size

ciphertext = cipher (plain(i), w, s_box, poly_mat, 1);

end