Add pkgProtocolContext for dbfv

dbfv/dbfv_benchmark_test.go

@@ -88,7 +88,7 @@ func benchRelinKeyGen(b *testing.B) {
 		}
 
 		p := new(Party)
-		p.RKGProtocol = NewEkgProtocol(bfvContext)
+		p.RKGProtocol = NewEkgProtocol(&parameters)
 		p.u = p.RKGProtocol.NewEphemeralKey(1.0 / 3.0)
 		p.s = sk0Shards[0].Get()
 		p.share1, p.share2, p.share3 = p.RKGProtocol.AllocateShares()

dbfv/dbfv_test.go

@@ -195,7 +195,7 @@ func testRelinKeyGen(t *testing.T) {
 
 			for i := range rkgParties {
 				p := new(Party)
-				p.RKGProtocol = NewEkgProtocol(bfvContext)
+				p.RKGProtocol = NewEkgProtocol(&parameters)
 				p.u = p.RKGProtocol.NewEphemeralKey(1.0 / 3.0)
 				p.s = sk0Shards[i].Get()
 				p.share1, p.share2, p.share3 = p.RKGProtocol.AllocateShares()
@@ -946,7 +946,7 @@ func Test_Relin_Marshalling(t *testing.T) {
 
 	t.Run(fmt.Sprintf("RLKG/N=%d/limbQ=%d/limbsP=%d", contextQ.N, len(contextQ.Modulus), len(contextPKeys.Modulus)), func(t *testing.T) {
 
-		rlk := NewEkgProtocol(bfvCtx)
+		rlk := NewEkgProtocol(params)
 		u := rlk.NewEphemeralKey(1 / 3.0)
 		sk := bfv.NewKeyGenerator(params).NewSecretKey()
 		log.Print("Starting to test marshalling for share one")

dbfv/relinkey_gen.go

@@ -7,11 +7,56 @@ import (
 	"math"
 )
 
+type pkgProtocolContext struct {
+	// Polynomial degree
+	n uint64
+
+	// Ternary and Gaussian samplers
+	gaussianSampler *ring.KYSampler
+
+	contextKeys   *ring.Context
+	contextPKeys  *ring.Context
+	specialPrimes []uint64
+}
+
+func newPkgProtocolContext(params *bfv.Parameters) *pkgProtocolContext {
+	n := params.N
+
+	contextKeys := ring.NewContext()
+	contextKeys.SetParameters(n, append(params.Qi, params.KeySwitchPrimes...))
+	err := contextKeys.GenNTTParams()
+	if err != nil {
+		panic(err)
+	}
+
+	contextPKeys := ring.NewContext()
+	contextPKeys.SetParameters(n, params.KeySwitchPrimes)
+	err = contextPKeys.GenNTTParams()
+	if err != nil {
+		panic(err)
+	}
+
+	specialPrimes := make([]uint64, len(params.KeySwitchPrimes))
+	for i := range params.KeySwitchPrimes {
+		specialPrimes[i] = params.KeySwitchPrimes[i]
+	}
+
+	gaussianSampler := contextKeys.NewKYSampler(params.Sigma, int(6*params.Sigma))
+
+	return &pkgProtocolContext{
+		n:               n,
+		gaussianSampler: gaussianSampler,
+		contextKeys:     contextKeys,
+		contextPKeys:    contextPKeys,
+		specialPrimes:   specialPrimes,
+	}
+}
+
 // RKGProtocol is the structure storing the parameters and state for a party in the collective relinearization key
 // generation protocol.
 type RKGProtocol struct {
 	ringContext     *ring.Context
-	bfvContext      *bfv.Context
+	context         *pkgProtocolContext
 	keyswitchprimes []uint64
 	alpha           uint64
 	beta            uint64
@@ -190,21 +235,22 @@ func (ekg *RKGProtocol) AllocateShares() (r1 RKGShareRoundOne, r2 RKGShareRoundT
 
 // NewEkgProtocol creates a new RKGProtocol object that will be used to generate a collective evaluation-key
 // among j parties in the given context with the given bit-decomposition.
-func NewEkgProtocol(context *bfv.Context) *RKGProtocol {
+func NewEkgProtocol(params *bfv.Parameters) *RKGProtocol {
+	context := newPkgProtocolContext(params)
 
 	ekg := new(RKGProtocol)
-	ekg.ringContext = context.ContextKeys()
-	ekg.bfvContext = context
+	ekg.ringContext = context.contextKeys
+	ekg.context = context
 
-	ekg.keyswitchprimes = make([]uint64, len(context.KeySwitchPrimes()))
-	for i, pi := range context.KeySwitchPrimes() {
+	ekg.keyswitchprimes = make([]uint64, len(context.specialPrimes))
+	for i, pi := range context.specialPrimes {
 		ekg.keyswitchprimes[i] = pi
 	}
 
 	ekg.alpha = uint64(len(ekg.keyswitchprimes))
 	ekg.beta = uint64(math.Ceil(float64(len(ekg.ringContext.Modulus)-len(ekg.keyswitchprimes)) / float64(ekg.alpha)))
 
-	ekg.gaussianSampler = context.GaussianSampler()
+	ekg.gaussianSampler = context.gaussianSampler
 
 	ekg.tmpPoly1 = ekg.ringContext.NewPoly()
 	ekg.tmpPoly2 = ekg.ringContext.NewPoly()
@@ -233,7 +279,7 @@ func (ekg *RKGProtocol) GenShareRoundOne(u, sk *ring.Poly, crp []*ring.Poly, sha
 
 	ekg.polypool.Copy(sk)
 
-	ekg.ringContext.MulScalarBigint(ekg.polypool, ekg.bfvContext.ContextPKeys().ModulusBigint, ekg.polypool)
+	ekg.ringContext.MulScalarBigint(ekg.polypool, ekg.context.contextPKeys.ModulusBigint, ekg.polypool)
 
 	ekg.ringContext.InvMForm(ekg.polypool, ekg.polypool)
 

examples/dbfv/pir/pir.go

@@ -103,7 +103,7 @@ func main() {
 
 	// Instantiation of each of the protocols needed for the pir example
 	ckg := dbfv.NewCKGProtocol(bfvctx)       // public key generation
-	rkg := dbfv.NewEkgProtocol(bfvctx)       // relineariation key generation
+	rkg := dbfv.NewEkgProtocol(params)       // relineariation key generation
 	rtg := dbfv.NewRotKGProtocol(params)     // rotation keys generation
 	cks := dbfv.NewCKSProtocol(params, 3.19) // collective public-key re-encryption
 

examples/dbfv/psi/psi.go

@@ -82,7 +82,7 @@ func main() {
 	}
 
 	ckg := dbfv.NewCKGProtocol(bfvctx)
-	rkg := dbfv.NewEkgProtocol(bfvctx)
+	rkg := dbfv.NewEkgProtocol(params)
 	pcks := dbfv.NewPCKSProtocol(bfvctx, 3.19)
 
 	P := make([]*party, N, N)