didier/paillier
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Do not export internal ThresholdKey functions

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Piotr Dyraga committed 2018-05-30 14:48:28 +02:00
1 parent e25bc358e8
commit adcb812a08
2 files changed
+26 -28
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thresholdkey.go
+15 -17
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@@ -17,17 +17,17 @@ type ThresholdKey struct {
}
// returns the value of (4*delta**2)** -1 mod n
func (this *ThresholdKey) CombineSharesConstant() *big.Int {
tmp := new(big.Int).Mul(FOUR, new(big.Int).Mul(this.Delta(), this.Delta()))
func (this *ThresholdKey) combineSharesConstant() *big.Int {
tmp := new(big.Int).Mul(FOUR, new(big.Int).Mul(this.delta(), this.delta()))
return (&big.Int{}).ModInverse(tmp, this.N)
}
// returns the factorial of the number of TotalNumberOfDecryptionServers
func (this *ThresholdKey) Delta() *big.Int {
func (this *ThresholdKey) delta() *big.Int {
return Factorial(this.TotalNumberOfDecryptionServers)
}
func (this *ThresholdKey) MakeVerificationBeforeCombiningPartialDecryptions(shares []*PartialDecryption) error {
func (this *ThresholdKey) makeVerificationBeforeCombiningPartialDecryptions(shares []*PartialDecryption) error {
if len(shares) < this.Threshold {
return errors.New("Threshold not meet")
}
@@ -41,17 +41,17 @@ func (this *ThresholdKey) MakeVerificationBeforeCombiningPartialDecryptions(shar
return nil
}
func (this *ThresholdKey) UpdateLambda(share1, share2 *PartialDecryption, lambda *big.Int) *big.Int {
func (this *ThresholdKey) updateLambda(share1, share2 *PartialDecryption, lambda *big.Int) *big.Int {
num := new(big.Int).Mul(lambda, big.NewInt(int64(-share2.Id)))
denom := big.NewInt(int64(share1.Id - share2.Id))
return new(big.Int).Div(num, denom)
}
func (this *ThresholdKey) ComputeLambda(share *PartialDecryption, shares []*PartialDecryption) *big.Int {
lambda := this.Delta()
func (this *ThresholdKey) computeLambda(share *PartialDecryption, shares []*PartialDecryption) *big.Int {
lambda := this.delta()
for _, share2 := range shares {
if share2.Id != share.Id {
lambda = this.UpdateLambda(share, share2, lambda)
lambda = this.updateLambda(share, share2, lambda)
}
}
return lambda
@@ -85,17 +85,17 @@ func (this *ThresholdKey) exp(a, b, c *big.Int) *big.Int {
func (this *ThresholdKey) computeDecryption(cprime *big.Int) *big.Int {
l := L(cprime, this.N)
return new(big.Int).Mod(new(big.Int).Mul(this.CombineSharesConstant(), l), this.N)
return new(big.Int).Mod(new(big.Int).Mul(this.combineSharesConstant(), l), this.N)
}
func (this *ThresholdKey) CombinePartialDecryptions(shares []*PartialDecryption) (*big.Int, error) {
if err := this.MakeVerificationBeforeCombiningPartialDecryptions(shares); err != nil {
if err := this.makeVerificationBeforeCombiningPartialDecryptions(shares); err != nil {
return nil, err
}
cprime := ONE
for _, share := range shares {
lambda := this.ComputeLambda(share, shares)
lambda := this.computeLambda(share, shares)
cprime = this.updateCprime(cprime, lambda, share)
}
@@ -143,7 +143,7 @@ type ThresholdPrivateKey struct {
func (this *ThresholdPrivateKey) Decrypt(c *big.Int) *PartialDecryption {
ret := new(PartialDecryption)
ret.Id = this.Id
exp := new(big.Int).Mul(this.Share, new(big.Int).Mul(TWO, this.Delta()))
exp := new(big.Int).Mul(this.Share, new(big.Int).Mul(TWO, this.delta()))
ret.Decryption = new(big.Int).Exp(c, exp, this.GetNSquare())
return ret
@@ -167,11 +167,10 @@ func (this *ThresholdPrivateKey) GetThresholdKey() *ThresholdKey {
return ret
}
func (this *ThresholdPrivateKey) ComputeZ(r, e *big.Int) *big.Int {
tmp := new(big.Int).Mul(e, this.Delta())
func (this *ThresholdPrivateKey) computeZ(r, e *big.Int) *big.Int {
tmp := new(big.Int).Mul(e, this.delta())
tmp = new(big.Int).Mul(tmp, this.Share)
return new(big.Int).Add(r, tmp)
}
func (this *ThresholdPrivateKey) computeHash(a, b, c4, ci2 *big.Int) *big.Int {
@@ -181,7 +180,6 @@ func (this *ThresholdPrivateKey) computeHash(a, b, c4, ci2 *big.Int) *big.Int {
hash.Write(c4.Bytes())
hash.Write(ci2.Bytes())
return new(big.Int).SetBytes(hash.Sum([]byte{}))
}
func (this *ThresholdPrivateKey) DecryptAndProduceZNP(c *big.Int, random io.Reader) (*PartialDecryptionZKP, error) {
@@ -208,7 +206,7 @@ func (this *ThresholdPrivateKey) DecryptAndProduceZNP(c *big.Int, random io.Read
pd.E = this.computeHash(a, b, c4, ci2)
pd.Z = this.ComputeZ(r, pd.E)
pd.Z = this.computeZ(r, pd.E)
return pd, nil
}