#include <conio.h>
// CS 1501 Fall 2002
// Some help and guidance for your Digital Signature assignment

#include <stdlib.h>  // needed for atoi and itoa
#include <NTL/ZZ.h>
#include <time.h>

main()
{
   unsigned char csig[48];  // overall array for signature
   unsigned char stamp[16] = "JR20021017004435";  // Example initials, date
                                // and time with NO separators index locations
                                // will be used for parsing

   ZZ modulus, other, zsig;  // ZZs for modulus, hash result and overall signature
   RandomLen(modulus, 128);  // example modulus
   RandomLen(other, 128);    // example hash result (you must calculate this
                             // in your program)

   unsigned char moda[16], othera[16];
   BytesFromZZ(moda, modulus, 16L); // Converting ZZs into 16 char strings
   BytesFromZZ(othera, other, 16L);

   for (int i = 0; i < 16; i++)     // Now the overall signature string is set
   {                                // very specifically -- 16 chars for each
        csig[i] = stamp[i];           // of the 3parts
        csig[i + 16] = moda[i];
        csig[i + 32] = othera[i];
   }

   ZZFromBytes(zsig, csig, 48L);    // This is the ZZ overall signature prior
                                    // to RSA encoding.  Once RSA decrypted,
                                    // follow directions as stated in the
                                    // assignment

   // Now we'll see how the ZZ is converted back to its parts.  Naturally, the
   // decrypted ZZ must first be read from the file (using >>) and then
   // RSA encrypted to reveal the signature ZZ

   ZZ newmod, newother;
   unsigned char newcsig[48], newstamp[16], newmoda[16], newothera[16];
   int newnum;

   BytesFromZZ(newcsig, zsig, 48L);  // First convert the sig ZZ back into a
                                     // sequence of bytes

   for (int i = 0; i < 16; i++)      // break it up into its components
   {
        newstamp[i] = newcsig[i];
        newmoda[i] = newcsig[i + 16];
        newothera[i] = newcsig[i + 32];
   }

   ZZFromBytes(newmod, newmoda, 16L); // ways
   ZZFromBytes(newother, newothera, 16L);

   // Check to see that the values match
   cout << "Original: " << endl;
   for (int i = 0; i < 16; i++)
       cout << stamp[i];
   cout << endl;
   cout << modulus << ":" << other << endl;
   cout << endl;

   cout << "Copies: " << endl;
   for (int i = 0; i < 16; i++)
       cout << newstamp[i];
   cout << endl;
   cout << newmod << ":" << newother << endl;
}