// Return in poly a polynomial with X^i encoded in all the slots
static void x2iInSlots(ZZX& poly, long i,
vector<ZZX>& xVec, const EncryptedArray& ea)
{
xVec.resize(ea.size());
ZZX x2i = ZZX(i,1);
for (long j=0; j<(long)xVec.size(); j++) xVec[j] = x2i;
ea.encode(poly, xVec);
}
// return a degree-d irreducible polynomial mod p
ZZX makeIrredPoly(long p, long d)
{
assert(d >= 1);
assert(ProbPrime(p));
if (d == 1) return ZZX(1, 1); // the monomial X
zz_pBak bak; bak.save();
zz_p::init(p);
return to_ZZX(BuildIrred_zz_pX(d));
}
void mapPowerfulToPoly(ZZX& poly,
const Vec<long>& pow,
const Vec<long>& divVec,
long m,
const ZZX& phimX)
{
long k = pow.length();
assert(divVec.length() == k);
long j = 0;
for (long i = 0; i < k; i++)
j += pow[i] * divVec[i];
j %= m;
ZZX f = ZZX(j, 1);
poly = f % phimX;
}
/**
* @brief Extract coefficients from ciphertext polynomial
* @param coeffs extracted coefficients
* @param ctxt ciphertext
* @param n extract "n" lowest degree coefficients
*/
void extractCoeffs(EncryptedArray& ea, vector<Ctxt>& coeffs, Ctxt& ctxt, long n) {
long d = ea.getDegree();
if (d < n) n = d;
coeffs.clear();
vector<Ctxt> conj;
for (int coeff = 0; coeff < n; ++coeff) {
vector<ZZX> LM(d);
LM[coeff] = ZZX(0, 1);
// "building" the linearized-polynomial coefficients
vector<ZZX> C(d);
ea.buildLinPolyCoeffs(C, LM);
coeffs.push_back(ctxt);
applyLinPoly1(ea, coeffs[coeff], C, conj);
}
}
void mapPowerfulToPoly(ZZX& poly,
const Vec<long>& pow,
const Vec<long>& divVec,
long m,
const ZZX& phimX)
{
long k = pow.length();
//OLD: assert(divVec.length() == k);
helib::assertEq(divVec.length(), k, "pow and divVec have different sizes");
long j = 0;
for (long i = 0; i < k; i++)
j += pow[i] * divVec[i];
j %= m;
ZZX f = ZZX(j, 1);
poly = f % phimX;
}
int main()
{
string * tmp_ptr;
long LLL, DDD, KKK ;
long m;
long ccc;
FHEcontext * context_ptr;
FHESecKey * fhekey_ptr;
EncryptedArray * ea_ptr;
LLL = 682; DDD=12; KKK=80;
/*
pair<long, long> m_c = get_m_c(LLL, DDD, KKK);
m = m_c.first;
ccc = m_c.second;
*/
m = 15709;
ccc = 3;
context_ptr = new FHEcontext(m, 2, 1);
buildModChain(*context_ptr, DDD, ccc);
fhekey_ptr = new FHESecKey(*context_ptr);
fhekey_ptr->clear();
fhekey_ptr->GenSecKey(64,2);
addSome1DMatrices(*fhekey_ptr);
const FHEPubKey & pub_key = *fhekey_ptr;
ZZX G;
G = ZZX(1,1);
ea_ptr = new EncryptedArray(*context_ptr, G);
// Test I/O, write context and public key, then try to read them back
cout << "KEY\n";
cout <<"L= " <<LLL<< " D= " << DDD<< " K= " << KKK << endl<< flush;
{
stringstream s1;
writeContextBase(s1, *context_ptr);
s1 << *context_ptr;
string s2 = s1.str();
cout << s2 << endl; // output context also to external cout
// Read back context from input stream (s3)
unsigned long m1, p1, r1;
stringstream s3(s2);
readContextBase(s3, m1, p1, r1);
FHEcontext c1(m1, p1, r1);
s3 >> c1;
assert(c1 == *context_ptr);
}
{
stringstream s1;
s1 << pub_key;
string s2 = s1.str();
cout << s2 <<"\nENDKEY" << endl; // output public key also to external cout
// Read back cpublic key from input stream (s3)
stringstream s3(s2);
FHEPubKey pk1(*context_ptr);
s3 >> pk1;
assert(pk1 == pub_key);
}
}
void TestIt(long R, long p, long r, long d, long c, long k, long w,
long L, long m)
{
cerr << "\n\n******** TestIt: R=" << R
<< ", p=" << p
<< ", r=" << r
<< ", d=" << d
<< ", c=" << c
<< ", k=" << k
<< ", w=" << w
<< ", L=" << L
<< ", m=" << m
<< endl;
FHEcontext context(m, p, r);
buildModChain(context, L, c);
// context.lazy = false;
if (context.lazy)
cerr << "LAZY REDUCTIONS\n";
else
cerr << "NON-LAZY REDUCTIONS\n";
context.zMStar.printout();
cerr << endl;
#ifdef DEBUG
cerr << context << endl;
#endif
FHESecKey secretKey(context);
const FHEPubKey& publicKey = secretKey;
secretKey.GenSecKey(w); // A Hamming-weight-w secret key
ZZX G;
if (d == 0) {
G = context.alMod.getFactorsOverZZ()[0];
d = deg(G);
}
else
G = makeIrredPoly(p, d);
cerr << "G = " << G << "\n";
cerr << "generating key-switching matrices... ";
addSome1DMatrices(secretKey); // compute key-switching matrices that we need
addFrbMatrices(secretKey); // compute key-switching matrices that we need
cerr << "done\n";
cerr << "computing masks and tables for rotation...";
EncryptedArray ea(context, G);
cerr << "done\n";
long nslots = ea.size();
// L selects even coefficients
vector<ZZX> LM(d);
for (long j = 0; j < d; j++)
if (j % 2 == 0) LM[j] = ZZX(j, 1);
vector<ZZX> C;
ea.buildLinPolyCoeffs(C, LM);
PlaintextArray p0(ea);
p0.random();
Ctxt c0(publicKey);
ea.encrypt(c0, publicKey, p0);
Ctxt res(c0);
applyLinPoly1(ea, res, C);
PlaintextArray pp0(ea);
ea.decrypt(res, secretKey, pp0);
p0.print(cout); cout << "\n";
pp0.print(cout); cout << "\n";
}
