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fix bug in LeveledSHERNS::EvalSubInPlace(Ciphertext<DCRTPoly>& cipher… #1217

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Merged
yspolyakov merged 1 commit into from
Jul 7, 2026
Merged

fix bug in LeveledSHERNS::EvalSubInPlace(Ciphertext<DCRTPoly>& cipher… #1217

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83 changes: 60 additions & 23 deletions src/pke/lib/schemerns/rns-leveledshe.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -29,8 +29,6 @@
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//==================================================================================

#define PROFILE

#include "cryptocontext.h"
#include "schemerns/rns-leveledshe.h"

Expand All @@ -39,6 +37,39 @@

namespace lbcrypto {

namespace {
inline ScalingTechnique GetScalingTechnique(const CiphertextImpl<DCRTPoly>& ct) {
return static_cast<const CryptoParametersRNS&>(*ct.GetCryptoParameters()).GetScalingTechnique();
}

// AdjustForAddOrSubInPlace() is a no-op when the operands share level, noise-scale degree and tower
// count (the plaintext overload additionally requires the plaintext element in EVALUATION format).
inline bool AdjustForAddOrSubIsNoOp(const CiphertextImpl<DCRTPoly>& a, const CiphertextImpl<DCRTPoly>& b) {
return a.GetLevel() == b.GetLevel() && a.GetNoiseScaleDeg() == b.GetNoiseScaleDeg() &&
a.GetElements()[0].GetNumOfElements() == b.GetElements()[0].GetNumOfElements();
}
inline bool AdjustForAddOrSubIsNoOp(const CiphertextImpl<DCRTPoly>& ct, const PlaintextImpl& pt) {
const auto& pe = pt.GetElement<DCRTPoly>();
return pt.GetLevel() == ct.GetLevel() && pt.GetNoiseScaleDeg() == ct.GetNoiseScaleDeg() &&
pe.GetFormat() == Format::EVALUATION && pe.GetNumOfElements() == ct.GetElements()[0].GetNumOfElements();
}

// AdjustForMultInPlace() is a no-op when the operands share level and tower count and either the
// scaling technique is FIXEDMANUAL (no rescale on mult) or both operands are already at depth 1.
inline bool AdjustForMultIsNoOp(const CiphertextImpl<DCRTPoly>& a, const CiphertextImpl<DCRTPoly>& b,
ScalingTechnique st) {
return a.GetLevel() == b.GetLevel() &&
a.GetElements()[0].GetNumOfElements() == b.GetElements()[0].GetNumOfElements() &&
(st == FIXEDMANUAL || (a.GetNoiseScaleDeg() == 1 && b.GetNoiseScaleDeg() == 1));
}
inline bool AdjustForMultIsNoOp(const CiphertextImpl<DCRTPoly>& ct, const PlaintextImpl& pt, ScalingTechnique st) {
const auto& pe = pt.GetElement<DCRTPoly>();
return ct.GetLevel() == pt.GetLevel() && pe.GetFormat() == Format::EVALUATION &&
pe.GetNumOfElements() == ct.GetElements()[0].GetNumOfElements() &&
(st == FIXEDMANUAL || (ct.GetNoiseScaleDeg() == 1 && pt.GetNoiseScaleDeg() == 1));
}
} // namespace

/////////////////////////////////////////
// SHE ADDITION
/////////////////////////////////////////
Expand All @@ -51,8 +82,8 @@ Ciphertext<DCRTPoly> LeveledSHERNS::EvalAdd(ConstCiphertext<DCRTPoly>& ciphertex
}

void LeveledSHERNS::EvalAddInPlace(Ciphertext<DCRTPoly>& ciphertext1, ConstCiphertext<DCRTPoly>& ciphertext2) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext1->GetCryptoParameters())->GetScalingTechnique();
if (st == NORESCALE) {
auto st = GetScalingTechnique(*ciphertext1);
if (st == NORESCALE || AdjustForAddOrSubIsNoOp(*ciphertext1, *ciphertext2)) {
EvalAddCoreInPlace(ciphertext1, ciphertext2);
}
else {
Expand Down Expand Up @@ -84,8 +115,8 @@ Ciphertext<DCRTPoly> LeveledSHERNS::EvalAdd(ConstCiphertext<DCRTPoly>& ciphertex
}

void LeveledSHERNS::EvalAddInPlace(Ciphertext<DCRTPoly>& ciphertext, ConstPlaintext& plaintext) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext->GetCryptoParameters())->GetScalingTechnique();
if (st == NORESCALE) {
auto st = GetScalingTechnique(*ciphertext);
if (st == NORESCALE || AdjustForAddOrSubIsNoOp(*ciphertext, *plaintext)) {
EvalAddCoreInPlace(ciphertext, plaintext->GetElement<DCRTPoly>());
}
else {
Expand Down Expand Up @@ -119,8 +150,8 @@ Ciphertext<DCRTPoly> LeveledSHERNS::EvalSub(ConstCiphertext<DCRTPoly>& ciphertex
}

void LeveledSHERNS::EvalSubInPlace(Ciphertext<DCRTPoly>& ciphertext1, ConstCiphertext<DCRTPoly>& ciphertext2) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext1->GetCryptoParameters())->GetScalingTechnique();
if (st == NORESCALE) {
auto st = GetScalingTechnique(*ciphertext1);
if (st == NORESCALE || AdjustForAddOrSubIsNoOp(*ciphertext1, *ciphertext2)) {
EvalSubCoreInPlace(ciphertext1, ciphertext2);
}
else {
Expand Down Expand Up @@ -152,9 +183,9 @@ Ciphertext<DCRTPoly> LeveledSHERNS::EvalSub(ConstCiphertext<DCRTPoly>& ciphertex
}

void LeveledSHERNS::EvalSubInPlace(Ciphertext<DCRTPoly>& ciphertext, ConstPlaintext& plaintext) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext->GetCryptoParameters())->GetScalingTechnique();
if (st == NORESCALE) {
EvalAddCoreInPlace(ciphertext, plaintext->GetElement<DCRTPoly>());
auto st = GetScalingTechnique(*ciphertext);
if (st == NORESCALE || AdjustForAddOrSubIsNoOp(*ciphertext, *plaintext)) {
EvalSubCoreInPlace(ciphertext, plaintext->GetElement<DCRTPoly>());
}
else {
auto ctmorphed = MorphPlaintext(plaintext, ciphertext);
Expand All @@ -181,8 +212,8 @@ void LeveledSHERNS::EvalSubMutableInPlace(Ciphertext<DCRTPoly>& ciphertext, Plai

Ciphertext<DCRTPoly> LeveledSHERNS::EvalMult(ConstCiphertext<DCRTPoly>& ciphertext1,
ConstCiphertext<DCRTPoly>& ciphertext2) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext1->GetCryptoParameters())->GetScalingTechnique();
if (st == NORESCALE)
auto st = GetScalingTechnique(*ciphertext1);
if (st == NORESCALE || AdjustForMultIsNoOp(*ciphertext1, *ciphertext2, st))
return EvalMultCore(ciphertext1, ciphertext2);

auto c1 = ciphertext1->Clone();
Expand Down Expand Up @@ -230,15 +261,21 @@ Ciphertext<DCRTPoly> LeveledSHERNS::EvalMult(ConstCiphertext<DCRTPoly>& cipherte
}

void LeveledSHERNS::EvalMultInPlace(Ciphertext<DCRTPoly>& ciphertext, ConstPlaintext& plaintext) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext->GetCryptoParameters())->GetScalingTechnique();
auto st = GetScalingTechnique(*ciphertext);
if (st == NORESCALE) {
EvalMultCoreInPlace(ciphertext, plaintext->GetElement<DCRTPoly>());
}
else {
auto ctmorphed = MorphPlaintext(plaintext, ciphertext);
AdjustForMultInPlace(ciphertext, ctmorphed);
EvalMultCoreInPlace(ciphertext, ctmorphed->GetElements()[0]);
ciphertext->SetNoiseScaleDeg(ciphertext->GetNoiseScaleDeg() + ctmorphed->GetNoiseScaleDeg());
if (AdjustForMultIsNoOp(*ciphertext, *plaintext, st)) {
EvalMultCoreInPlace(ciphertext, plaintext->GetElement<DCRTPoly>());
ciphertext->SetNoiseScaleDeg(ciphertext->GetNoiseScaleDeg() + plaintext->GetNoiseScaleDeg());
}
else {
auto ctmorphed = MorphPlaintext(plaintext, ciphertext);
AdjustForMultInPlace(ciphertext, ctmorphed);
EvalMultCoreInPlace(ciphertext, ctmorphed->GetElements()[0]);
ciphertext->SetNoiseScaleDeg(ciphertext->GetNoiseScaleDeg() + ctmorphed->GetNoiseScaleDeg());
}
}
}

Expand All @@ -251,7 +288,7 @@ Ciphertext<DCRTPoly> LeveledSHERNS::EvalMultMutable(Ciphertext<DCRTPoly>& cipher
// TODO (Andrey) : This part is only used in CKKS scheme
result->SetScalingFactor(ciphertext->GetScalingFactor() * ctmorphed->GetScalingFactor());
// TODO (Andrey) : This part is only used in BGV scheme
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext->GetCryptoParameters())->GetScalingTechnique();
auto st = GetScalingTechnique(*ciphertext);
if (st == FLEXIBLEAUTO || st == FLEXIBLEAUTOEXT)
result->SetScalingFactorInt(ciphertext->GetScalingFactorInt().ModMul(
ctmorphed->GetScalingFactorInt(), ciphertext->GetCryptoParameters()->GetPlaintextModulus()));
Expand All @@ -268,7 +305,7 @@ void LeveledSHERNS::EvalMultMutableInPlace(Ciphertext<DCRTPoly>& ciphertext, Pla
// TODO (Andrey) : This part is only used in CKKS scheme
ciphertext->SetScalingFactor(ciphertext->GetScalingFactor() * ctmorphed->GetScalingFactor());
// TODO (Andrey) : This part is only used in BGV scheme
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext->GetCryptoParameters())->GetScalingTechnique();
auto st = GetScalingTechnique(*ciphertext);
if (st == FLEXIBLEAUTO || st == FLEXIBLEAUTOEXT)
ciphertext->SetScalingFactorInt(ciphertext->GetScalingFactorInt().ModMul(
ctmorphed->GetScalingFactorInt(), ciphertext->GetCryptoParameters()->GetPlaintextModulus()));
Expand Down Expand Up @@ -315,7 +352,7 @@ Ciphertext<DCRTPoly> LeveledSHERNS::ModReduce(ConstCiphertext<DCRTPoly>& ciphert
}

void LeveledSHERNS::ModReduceInPlace(Ciphertext<DCRTPoly>& ciphertext, size_t levels) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext->GetCryptoParameters())->GetScalingTechnique();
auto st = GetScalingTechnique(*ciphertext);
if (st == FIXEDMANUAL)
ModReduceInternalInPlace(ciphertext, levels);
}
Expand All @@ -335,7 +372,7 @@ Ciphertext<DCRTPoly> LeveledSHERNS::LevelReduce(ConstCiphertext<DCRTPoly>& ciphe
// TODO (Andrey) : remove evalKey as unused
void LeveledSHERNS::LevelReduceInPlace(Ciphertext<DCRTPoly>& ciphertext, const EvalKey<DCRTPoly> evalKey,
size_t levels) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext->GetCryptoParameters())->GetScalingTechnique();
auto st = GetScalingTechnique(*ciphertext);
if (st == NORESCALE)
OPENFHE_THROW("Not implemented for NORESCALE rescaling technique");
if (st == FIXEDMANUAL && levels > 0)
Expand Down Expand Up @@ -477,7 +514,7 @@ void LeveledSHERNS::AdjustForAddOrSubInPlace(Ciphertext<DCRTPoly>& ciphertext1,
}

void LeveledSHERNS::AdjustForMultInPlace(Ciphertext<DCRTPoly>& ciphertext1, Ciphertext<DCRTPoly>& ciphertext2) const {
auto st = std::dynamic_pointer_cast<CryptoParametersRNS>(ciphertext1->GetCryptoParameters())->GetScalingTechnique();
auto st = GetScalingTechnique(*ciphertext1);
if (st == FIXEDMANUAL)
AdjustLevelsInPlace(ciphertext1, ciphertext2);
else if (st != NORESCALE)
Expand Down