/* ==========================================================================
Encryption Process of Matsumoto Imai
The program loads the public key from the file public_key.txt 
and encrypts a randomly generated message
the ciphertext is stored in ciphertext.txt
===============================================================================*/

printf "************************************************\n";
printf "*** Matsumoto-Imai Cryptosystem - Encryption *** \n";
printf "************************************************ \n \n";

timet:=Cputime();
load "public_key.txt";

Vn:=VectorSpace(GF,n);
message:=Random(Vn); // random message

for loop:=1 to n do
	for i:=1 to n do
		Pk[loop]:=Evaluate(Pk[loop],x[i],message[i]);
	end for;
end for;

ciphertext:=Vn!(Pk);



print "MI decrypt time:",timet;
PrintFile("times_encrypt",Cputime(timet));


printf "message:= %o \n \n",message;
printf "ciphertext:= %o \n \n", ciphertext;

printf"Write ciphertext.txt \n \n";
SetOutputFile("ciphertext.txt":Overwrite:=true);
printf "Vn:=VectorSpace(GF,n); \n \n";
printf "message:= Vn!(%o); \n \n", Eltseq(message);
printf "ciphertext:= Vn!(%o); \n \n", Eltseq(ciphertext);
UnsetOutputFile();