parmfactory.h

// @file parmfactory.h parameter factory.
// @author TPOC: contact@palisade-crypto.org
//
// @copyright Copyright (c) 2019, New Jersey Institute of Technology (NJIT)
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// modification, are permitted provided that the following conditions are met:
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// this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
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#ifndef SRC_CORE_LIB_UTILS_PARMFACTORY_H_
#define SRC_CORE_LIB_UTILS_PARMFACTORY_H_

// useful for testing

#include <memory>
#include <vector>

#include "lattice/dcrtpoly.h"
#include "math/backend.h"
#include "math/distrgen.h"

#include "utils/inttypes.h"

#include "lattice/elemparams.h"
#include "lattice/ildcrtparams.h"
#include "lattice/ilelement.h"
#include "lattice/ilparams.h"
#include "lattice/poly.h"

using namespace lbcrypto;

template <typename I>
inline shared_ptr<ILDCRTParams<I>> GenerateDCRTParams(usint m, usint numOfTower,
                                                      usint pbits) {
  DEBUG_FLAG(false);
  DEBUG("in GenerateDCRTParams");
  DEBUGEXP(m);
  DEBUGEXP(numOfTower);
  DEBUGEXP(pbits);
  if (numOfTower == 0) {
    PALISADE_THROW(math_error, "Can't make parms with numOfTower == 0");
  }

  std::vector<NativeInteger> moduli(numOfTower);
  std::vector<NativeInteger> rootsOfUnity(numOfTower);

  NativeInteger q = FirstPrime<NativeInteger>(pbits, m);
  I modulus(1);

  usint j = 0;
  DEBUGEXP(q);

  for (;;) {
    moduli[j] = q;
    rootsOfUnity[j] = RootOfUnity(m, q);
    modulus = modulus * I(q.ConvertToInt());
    DEBUG("j " << j << " modulus " << q << " rou " << rootsOfUnity[j]);
    if (++j == numOfTower) break;

    q = NextPrime(q, m);
  }

  auto params = std::make_shared<ILDCRTParams<I>>(m, moduli, rootsOfUnity);

  return params;
}

#endif /* SRC_CORE_LIB_UTILS_PARMFACTORY_H_ */