/*
  Author:  Pate Williams (c) 1997

  Exercise 9.6
  "Suppose that Alice is using the Quisquater Scheme
  with p = 503, q = 379, and b = 509.
  (a) Suppose that Alice's secret u = 155863.
      Compute v.
  (b) Suppose that k = 123845. Compute gamma.
  (c) Suppose that Bob issues the challenge r = 487.
      Compute Alice's response y.
  (d) Perform Bob's calculation to verify y."
  -Douglas R. Stinson-
  See "Cryptography: Theory and Practice" by
  Douglas R. Stinson page 304.
*/

#include <stdio.h>
#include "lip.h"

int main(void)
{
  long b = 509, k = 123845, p = 503, q = 379;
  long n = p * q, r = 487, u = 155863;
  verylong za = 0, zb = 0, zc = 0, zd = 0, zk = 0;
  verylong zn = 0, zr = 0, zu = 0, zv = 0, zy = 0;
  verylong zgamma = 0;

  zintoz(b, &zb);
  zintoz(k, &zk);
  zintoz(n, &zn);
  zintoz(r, &zr);
  zintoz(u, &zu);
  zexpmod(zk, zb, zn, &zgamma);
  zexpmod(zu, zr, zn, &za);
  zmulmod(za, zk, zn, &zy);
  zinvmod(zu, zn, &za);
  zexpmod(za, zb, zn, &zv);
  zexpmod(zv, zr, zn, &za);
  zexpmod(zy, zb, zn, &zc);
  zmulmod(za, zc, zn, &zd);
  printf("p = %ld\n", p);
  printf("q = %ld\n", q);
  printf("b = %ld\n", b);
  printf("n = %ld\n", n);
  printf("k = %ld\n", k);
  printf("r = %ld\n", r);
  printf("u = %ld\n", u);
  printf("v = ");
  zwriteln(zv);
  printf("gamma = ");
  zwriteln(zgamma);
  printf("y = ");
  zwriteln(zy);
  if (zcompare(zd, zgamma) == 0)
    printf("Bob has verified y\n");
  else
    printf("Bob did no verify y\n");
  zfree(&za);
  zfree(&zb);
  zfree(&zc);
  zfree(&zd);
  zfree(&zk);
  zfree(&zn);
  zfree(&zr);
  zfree(&zu);
  zfree(&zv);
  zfree(&zy);
  zfree(&zgamma);
  return 0;
}