%%                               ElGamal PKC%% Functions:%% pub_key_gen% encrypt(p, Alpha, Betaa, m)% decrypt(y1, y2)%%%% Use:% % pub_key_gen - Generates the public key for the receiver.  This function%		requires no arguments and simply chooses a large prime p%		of a maximum size of 128 bits.  The receiver is to type %               this at the beginning to compute his or her publick key.%% ELGencrypt()- Encrypts the sender's message.  This function takes 4 inputs.%		These inputs are the published values of p, Alpha, and Betaa.%		The 4th input is the message that the sender plans to send.%%		This function is called from within the encrypt.m script as%		the sender does not need to call it explicitly but only needs%		to type encrypt followed by the message after being prompted.%%		The message cannot contain any spaces and if it is too long%		will generate an error.  If a long message needs to be sent%		the sender will need to break it up into manageable portions%		and send each portion individually by calling the encrypt %		function for each piece of the message.%		%		The sender must allow the receiver to decrypt each part of %		the message before sending the next part.%%		The size of the message depends on the chosen p.%% decrypt()   - Decrypts the message encrypted by the sender.  The receiver%		supplies this function with the values produced by encrypt().%		These values are y1 and y2 and are the only arguments needed% 		for the function to decrypt the ciphertext.	%% Note:  	The user simply calls these functions and uses the variables %	 	within the calls (i.e p, Alpha, Betaa, y1, y1) instead of %	 	copying the values of those into the arguments.  % % Secret key  - It is important to note that the secret key for this PKC is %		already set to a predetermined value.  For this to change you%		must manually edit the code of pub_key_gen.  The private key%		is stored in variable 'a'. %		greetingdisp(' ')disp(' ')answer = input('Would you like to continue and call the public key generator \nfunction? y/n\n\n','s')if (answer == 'y')   pub_key_genelse   disp('If you want to run this program again simply type "elgamal" at the')   disp('MATLAB prompt.  To avoid the start screen you may directly type')    disp('"pub_key_gen" to generate your public key.')end