C++ (Cpp) mpiMul Examples

Example #1

File: rsa.c Project: frankzzcn/M2_SE_RTOS_Project

error_t rsadp(const RsaPrivateKey *key, const Mpi *c, Mpi *m)
{
   error_t error;
   Mpi m1;
   Mpi m2;
   Mpi h;

   //The ciphertext representative c shall be between 0 and n - 1
   if(mpiCompInt(c, 0) < 0 || mpiComp(c, &key->n) >= 0)
      return ERROR_OUT_OF_RANGE;

   //Initialize multiple-precision integers
   mpiInit(&m1);
   mpiInit(&m2);
   mpiInit(&h);

   //Use the Chinese remainder algorithm?
   if(key->n.size && key->p.size && key->q.size &&
      key->dp.size && key->dq.size && key->qinv.size)
   {
      //Compute m1 = c ^ dP mod p
      MPI_CHECK(mpiExpMod(&m1, c, &key->dp, &key->p));
      //Compute m2 = c ^ dQ mod q
      MPI_CHECK(mpiExpMod(&m2, c, &key->dq, &key->q));
      //Let h = (m1 - m2) * qInv mod p
      MPI_CHECK(mpiSub(&h, &m1, &m2));
      MPI_CHECK(mpiMulMod(&h, &h, &key->qinv, &key->p));
      //Let m = m2 + q * h
      MPI_CHECK(mpiMul(m, &key->q, &h));
      MPI_CHECK(mpiAdd(m, m, &m2));
   }
   //Use modular exponentiation?
   else if(key->n.size && key->d.size)
   {
      //Let m = c ^ d mod n
      error = mpiExpMod(m, c, &key->d, &key->n);
   }
   //Invalid parameters?
   else
   {
      //Report an error
      error = ERROR_INVALID_PARAMETER;
   }

end:
   //Free previously allocated memory
   mpiFree(&m1);
   mpiFree(&m2);
   mpiFree(&h);

   //Return status code
   return error;
}

Example #2

File: ec.c Project: nandojve/embedded

error_t ecSqrMod(const EcDomainParameters *params, Mpi *r, const Mpi *a)
{
   error_t error;

   //Compute R = A ^ 2
   MPI_CHECK(mpiMul(r, a, a));

   //Compute R = (A ^ 2) mod p
   if(params->mod != NULL)
   {
      MPI_CHECK(params->mod(r, &params->p));
   }
   else
   {
      MPI_CHECK(mpiMod(r, r, &params->p));
   }

end:
   //Return status code
   return error;
}