static void add1Dmats4dim(FHESecKey& sKey, long i, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
computeParams(context,m,i); // defines vars: native, ord, gi, g2md, giminv, g2mdminv
/* MAUTO vector<long> vals; */
for (long j=1,val=gi; j < ord; j++) {
// From s(X^val) to s(X)
sKey.GenKeySWmatrix(1, val, keyID, keyID);
if (!native) { // also from s(X^{g^{i-ord}}) to s(X)
long val2 = MulModPrecon(val,g2md,m,g2mdminv);
sKey.GenKeySWmatrix(1, val2, keyID, keyID);
/* MAUTO vals.push_back(val2); */
}
/* MAUTO vals.push_back(val); */
val = MulModPrecon(val, gi, m, giminv); // val *= g mod m (= g^{j+1})
}
if (!native) {
sKey.GenKeySWmatrix(1, context.zMStar.genToPow(i, -ord), keyID, keyID);
}
/* MAUTO
sKey.resetTree(i,keyID); // remove existing tree, if any
sKey.add2tree(i, 1, vals, keyID);
*/
}
static void addMinimal1Dmats4dim(FHESecKey& sKey, long i, long keyID)
{
const PAlgebra& zMStar = sKey.getContext().zMStar;
long ord;
bool native;
if (i != -1) {
ord = zMStar.OrderOf(i);
native = zMStar.SameOrd(i);\
}
else {
// Frobenius
ord = zMStar.getOrdP();
native = true;
}
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, 1), keyID, keyID);
if (!native)
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, -ord), keyID, keyID);
if (ord > FHE_KEYSWITCH_MIN_THRESH) {
long g = KSGiantStepSize(ord);
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, g), keyID, keyID);
}
sKey.setKSStrategy(i, FHE_KSS_MIN);
}
// generate only matrices of the form s(X^{g^i})->s(X), but not all of them.
// For a generator g whose order is larger than bound, generate only enough
// matrices for the giant-step/baby-step procedures (2*sqrt(ord(g))of them).
void addSome1DMatrices(FHESecKey& sKey, long bound, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
// key-switching matrices for the automorphisms
for (long i = 0; i < (long)context.zMStar.numOfGens(); i++) {
// For generators of small order, add all the powers
if (bound >= (long)context.zMStar.OrderOf(i))
for (long j = 1; j < (long)context.zMStar.OrderOf(i); j++) {
long val = PowerMod(context.zMStar.ZmStarGen(i), j, m); // val = g^j
// From s(X^val) to s(X)
sKey.GenKeySWmatrix(1, val, keyID, keyID);
if (!context.zMStar.SameOrd(i))
// also from s(X^{1/val}) to s(X)
sKey.GenKeySWmatrix(1, InvMod(val,m), keyID, keyID);
}
else { // For generators of large order, add only some of the powers
long num = SqrRoot(context.zMStar.OrderOf(i)); // floor(ord^{1/2})
if (num*num < (long) context.zMStar.OrderOf(i)) num++; // ceil(ord^{1/2})
// VJS: the above two lines replaces the following inexact calculation
// with an exact calculation
// long num = ceil(sqrt((double)context.zMStar.OrderOf(i)));
for (long j=1; j <= num; j++) { // Add matrices for g^j and g^{j*num}
long val1 = PowerMod(context.zMStar.ZmStarGen(i), j, m); // g^j
long val2 = PowerMod(context.zMStar.ZmStarGen(i),num*j,m);// g^{j*num}
if (j < num) {
sKey.GenKeySWmatrix(1, val1, keyID, keyID);
sKey.GenKeySWmatrix(1, val2, keyID, keyID);
}
if (!context.zMStar.SameOrd(i)) {
// sKey.GenKeySWmatrix(1, InvMod(val1,m), keyID, keyID);
sKey.GenKeySWmatrix(1, InvMod(val2,m), keyID, keyID);
}
}
// VJS: experimantal feature...because the replication code
// uses rotations by -1, -2, -4, -8, we add a few
// of these as well...only the small ones are important,
// and we only need them if SameOrd(i)...
// Note: we do indeed get a nontrivial speed-up
if (context.zMStar.SameOrd(i)) {
for (long k = 1; k <= num; k = 2*k) {
long j = context.zMStar.OrderOf(i) - k;
long val = PowerMod(context.zMStar.ZmStarGen(i), j, m); // val = g^j
sKey.GenKeySWmatrix(1, val, keyID, keyID);
}
}
}
}
sKey.setKeySwitchMap(); // re-compute the key-switching map
}
// generate all matrices of the form s(X^{g^i})->s(X) for generators g of
// Zm* /<2> and i<ord(g). If g has different orders in Zm* and Zm* /<2>
// then generate also matrices of the form s(X^{g^{-i}})->s(X)
void add1DMatrices(FHESecKey& sKey, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
// key-switching matrices for the automorphisms
for (long i = 0; i < (long)context.zMStar.numOfGens(); i++) {
for (long j = 1; j < (long)context.zMStar.OrderOf(i); j++) {
long val = PowerMod(context.zMStar.ZmStarGen(i), j, m); // val = g^j
// From s(X^val) to s(X)
sKey.GenKeySWmatrix(1, val, keyID, keyID);
if (!context.zMStar.SameOrd(i))
// also from s(X^{1/val}) to s(X)
sKey.GenKeySWmatrix(1, InvMod(val,m), keyID, keyID);
}
}
sKey.setKeySwitchMap(); // re-compute the key-switching map
}
void addTheseMatrices(FHESecKey& sKey,
const std::set<long>& automVals, long keyID)
{
std::set<long>::iterator it;
for (it=automVals.begin(); it!=automVals.end(); ++it) {
long k = *it;
sKey.GenKeySWmatrix(1, k, keyID, keyID);
}
sKey.setKeySwitchMap(); // re-compute the key-switching map
}
// Generate all Frobenius matrices of the form s(X^{2^i})->s(X)
void addFrbMatrices(FHESecKey& sKey, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
for (long j = 1; j < (long)context.zMStar.getOrdP(); j++) {
long val = PowerMod(context.zMStar.getP(), j, m); // val = p^j mod m
sKey.GenKeySWmatrix(1, val, keyID, keyID);
}
sKey.setKeySwitchMap(); // re-compute the key-switching map
}
// A maximalistic approach: generate matrices s(X^e)->s(X) for all e \in Zm*
void addAllMatrices(FHESecKey& sKey, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
// key-switching matrices for the automorphisms
for (long i = 0; i < m; i++) {
if (!context.zMStar.inZmStar(i)) continue;
sKey.GenKeySWmatrix(1, i, keyID, keyID);
}
sKey.setKeySwitchMap(); // re-compute the key-switching map
}
// same as above, but uses BS/GS strategy
static void addSome1Dmats4dim(FHESecKey& sKey, long i, long bound, long keyID)
{
const PAlgebra& zMStar = sKey.getContext().zMStar;
long ord;
bool native;
if (i != -1) {
ord = zMStar.OrderOf(i);
native = zMStar.SameOrd(i);\
}
else {
// Frobenius
ord = zMStar.getOrdP();
native = true;
}
long g = KSGiantStepSize(ord);
// baby steps
for (long j = 1; j < g; j++)
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, j), keyID, keyID);
// giant steps
for (long j = g; j < ord; j += g)
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, j), keyID, keyID);
if (!native)
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, -ord), keyID, keyID);
sKey.setKSStrategy(i, FHE_KSS_BSGS);
// NOTE: the old code also added matrices for ord-2^k for small k,
// in the case of (native && i<context.zMStar.numOfGens()).
// This supposedly speeds up the replication code, but for now
// we are leaving this out, for simplicity. Also, it is a waste
// of space for applications that don't use replication.
}
// adds all matrices for dim i.
// i == -1 => Frobenius (NOTE: in matmul1D, i ==#gens means something else,
// so it is best to avoid that).
static void add1Dmats4dim(FHESecKey& sKey, long i, long keyID)
{
const PAlgebra& zMStar = sKey.getContext().zMStar;
long ord;
bool native;
if (i != -1) {
ord = zMStar.OrderOf(i);
native = zMStar.SameOrd(i);\
}
else {
// Frobenius
ord = zMStar.getOrdP();
native = true;
}
for (long j = 1; j < ord; j++)
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, j), keyID, keyID);
if (!native)
sKey.GenKeySWmatrix(1, zMStar.genToPow(i, -ord), keyID, keyID);
sKey.setKSStrategy(i, FHE_KSS_FULL);
}
// Generate all key-switching matrices for a given permutation network
void addMatrices4Network(FHESecKey& sKey, const PermNetwork& net, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
for (long i=0; i<net.depth(); i++) {
long e = net.getLayer(i).getE();
long gIdx = net.getLayer(i).getGenIdx();
long g = context.zMStar.ZmStarGen(gIdx);
long g2e = PowerMod(g, e, m); // g^e mod m
const Vec<long>&shamts = net.getLayer(i).getShifts();
for (long j=0; j<shamts.length(); j++) {
if (shamts[j]==0) continue;
long val = PowerMod(g2e, shamts[j], m);
sKey.GenKeySWmatrix(1, val, keyID, keyID);
}
}
sKey.setKeySwitchMap(); // re-compute the key-switching map
}
static void addSome1Dmats4dim(FHESecKey& sKey, long i, long bound, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
computeParams(context,m,i); // defines vars: native, ord, gi, g2md, giminv, g2mdminv
long baby, giant;
std::tie(baby,giant) = computeSteps(ord, bound, native);
for (long j=1,val=gi; j<=baby; j++) { // Add matrices for baby steps
sKey.GenKeySWmatrix(1, val, keyID, keyID);
if (!native) {
long val2 = MulModPrecon(val,g2md,m,g2mdminv);
sKey.GenKeySWmatrix(1, val2, keyID, keyID);
}
val = MulModPrecon(val, gi, m, giminv); // val *= g mod m (= g^{j+1})
}
long gb = PowerMod(gi,baby,m); // g^baby
NTL::mulmod_precon_t gbminv = PrepMulModPrecon(gb, m);
for (long j=2,val=gb; j < giant; j++) { // Add matrices for giant steps
val = MulModPrecon(val, gb, m, gbminv); // val = g^{(j+1)*baby}
sKey.GenKeySWmatrix(1, val, keyID, keyID);
}
if (!native) {
sKey.GenKeySWmatrix(1, context.zMStar.genToPow(i, -ord), keyID, keyID);
}
// VJS: experimantal feature...because the replication code
// uses rotations by -1, -2, -4, -8, we add a few
// of these as well...only the small ones are important,
// and we only need them if SameOrd(i)...
// Note: we do indeed get a nontrivial speed-up
if (native && i<context.zMStar.numOfGens()) {
for (long k = 1; k < giant; k = 2*k) {
long j = ord - k;
long val = PowerMod(gi, j, m); // val = g^j
sKey.GenKeySWmatrix(1, val, keyID, keyID);
}
}
#if 0
MAUTO
// build the tree for this dimension, the internal nodes are 1 and
// (subset of) gi^{giant}, gi^{2*giant}, ..., gi^{baby*giant}. We
MAUTO sKey.resetTree(i,keyID); // remove existing tree, if any
// keep a list of all the elements that are covered by the tree so far,
// initialized to only the root (=1).
std::unordered_set<long> covered({1});
// Make a list of the automorphisms for this dimension
std::vector<long> autos;
for (long j=1,val=gi; j<ord; j++) {
// Do we have matrices for val and/or val/gi^{di}?
if (!native) {
long val2 = MulModPrecon(val, g2md, m, g2mdminv);
if (sKey.haveKeySWmatrix(1,val2,keyID,keyID)) {
autos.push_back(val2);
}
}
if (sKey.haveKeySWmatrix(1,val,keyID,keyID)) {
autos.push_back(val);
}
val = MulModPrecon(val, gi, m, giminv); // g^{j+1}
}
// Insert internal nodes and their children to tree
for (long j=0,fromVal=1; j<giant; j++) {
NTL::mulmod_precon_t fromminv = PrepMulModPrecon(fromVal, m);
vector<long> children;
for (long k: autos) {
long toVal = MulModPrecon(k, fromVal, m, fromminv);
if (covered.count(toVal)==0) { // toVal not covered yet
covered.insert(toVal);
children.push_back(toVal);
}
}
if (!children.empty()) { // insert fromVal with its children
sKey.add2tree(i, fromVal, children, keyID);
}
fromVal = MulModPrecon(fromVal, gb, m, gbminv); // g^{(j+1)*baby}
}
// Sanity-check, did we cover everything?
long toCover = native? ord: (2*ord-1);
if (covered.size()<toCover)
cerr << "**Warning: order-"<<ord<<" dimension, covered "<<covered.size()
<< " of "<<toCover<<endl;
#endif
}