Generate the digital AWGN signal n[k] (sampled n(t)) by generating zero mean
Gaussian random variables independently (separately) for each k MATLAB function random.
替代加密:
A B C D E F G H I J K L M N O P Q R S T U V W 密文
Y Z D M R N H X J L I O Q U W A C B E G F K P 明文
X Y Z
T S V
I HAVE A DREAM！#
密文？？
用ARM編程實現替代加密。
