encoding.go

@@ -59,7 +59,7 @@ type dbThresholdKey struct {
 	N                              string
 }
 
-func (this *dbThresholdKey) FromThresholdKey(key *ThresholdKey) {
+func (this *dbThresholdKey) FromThresholdPublicKey(key *ThresholdPublicKey) {
 	this.TotalNumberOfDecryptionServers = key.TotalNumberOfDecryptionServers
 	this.Threshold = key.Threshold
 	this.V = fmt.Sprintf("%x", key.V)
@@ -70,7 +70,7 @@ func (this *dbThresholdKey) FromThresholdKey(key *ThresholdKey) {
 	}
 }
 
-func (this *dbThresholdKey) ToThresholdKey(key *ThresholdKey) error {
+func (this *dbThresholdKey) ToThresholdPublicKey(key *ThresholdPublicKey) error {
 	key.TotalNumberOfDecryptionServers = this.TotalNumberOfDecryptionServers
 	key.Threshold = this.Threshold
 	oks := make([]bool, 2)
@@ -91,18 +91,18 @@ func (this *dbThresholdKey) ToThresholdKey(key *ThresholdKey) error {
 	return nil
 }
 
-func (this *ThresholdKey) GetBSON() (interface{}, error) {
+func (this *ThresholdPublicKey) GetBSON() (interface{}, error) {
 	r := new(dbThresholdKey)
-	r.FromThresholdKey(this)
+	r.FromThresholdPublicKey(this)
 	return r, nil
 }
 
-func (this *ThresholdKey) SetBSON(raw bson.Raw) error {
+func (this *ThresholdPublicKey) SetBSON(raw bson.Raw) error {
 	r := new(dbThresholdKey)
 	if err := raw.Unmarshal(r); err != nil {
 		return err
 	}
-	return r.ToThresholdKey(this)
+	return r.ToThresholdPublicKey(this)
 }
 
 type dbPrivateKey struct {
@@ -175,7 +175,7 @@ func (this *dbPartialDecryptionZKP) FromPartialDecryptionZKP(pd *PartialDecrypti
 }
 
 func (this *dbPartialDecryptionZKP) ToPartialDecryptionZKP(pd *PartialDecryptionZKP) error {
-	pd.Key = new(ThresholdKey)
+	pd.Key = new(ThresholdPublicKey)
 
 	var oks = make([]bool, 6)
 

encoding_test.go

@@ -81,7 +81,7 @@ func TestGetBSONEmptyKey(t *testing.T) {
 
 func TestPartialDecryptionZKPJsonification(t *testing.T) {
 	pd := new(PartialDecryptionZKP)
-	pd.Key = new(ThresholdKey)
+	pd.Key = new(ThresholdPublicKey)
 	pd.Key.Threshold = 98
 	pd.Key.TotalNumberOfDecryptionServers = 230
 	pd.Id = 1
@@ -99,7 +99,7 @@ func TestPartialDecryptionZKPJsonification(t *testing.T) {
 
 func TestPartialDecryptionZKPBSONification(t *testing.T) {
 	pd := new(PartialDecryptionZKP)
-	pd.Key = new(ThresholdKey)
+	pd.Key = new(ThresholdPublicKey)
 	pd.Key.Threshold = 98
 	pd.Key.TotalNumberOfDecryptionServers = 230
 	pd.Id = 1
@@ -116,12 +116,12 @@ func TestPartialDecryptionZKPBSONification(t *testing.T) {
 }
 
 func TestThresholdKeyBSON(t *testing.T) {
-	key := &ThresholdKey{
+	key := &ThresholdPublicKey{
 		PublicKey:                      PublicKey{b(9)},
 		TotalNumberOfDecryptionServers: 7,
 		Threshold:                      6,
 		V:                              b(3),
 		Vi:                             []*big.Int{b(2), b(34)},
 	}
-	AssertBSONIsGood(key, new(ThresholdKey), t)
+	AssertBSONIsGood(key, new(ThresholdPublicKey), t)
 }

thresholdkey.go

@@ -23,7 +23,7 @@ import (
 //               A Generalization of Paillier’s Public-Key System
 //               with Applications to Electronic Voting
 //               Aarhus University, Dept. of Computer Science, BRICS
-type ThresholdKey struct {
+type ThresholdPublicKey struct {
 	PublicKey
 	TotalNumberOfDecryptionServers int
 	Threshold                      int
@@ -34,21 +34,21 @@ type ThresholdKey struct {
 // Returns the value of [(4*delta^2)]^-1  mod n.
 // It is a constant value for the given `ThresholdKey` and is used in the last
 // step of share combining.
-func (tk *ThresholdKey) combineSharesConstant() *big.Int {
+func (tk *ThresholdPublicKey) combineSharesConstant() *big.Int {
 	tmp := new(big.Int).Mul(FOUR, new(big.Int).Mul(tk.delta(), tk.delta()))
 	return (&big.Int{}).ModInverse(tmp, tk.N)
 }
 
 // Returns the factorial of the number of `TotalNumberOfDecryptionServers`.
 // It is a contant value for the given `ThresholdKey`.
-func (tk *ThresholdKey) delta() *big.Int {
+func (tk *ThresholdPublicKey) delta() *big.Int {
 	return Factorial(tk.TotalNumberOfDecryptionServers)
 }
 
 // Checks if the number of received, unique shares is less than the
 // required threshold.
 // This method does not execute ZKP on received shares.
-func (tk *ThresholdKey) makeVerificationBeforeCombiningPartialDecryptions(shares []*PartialDecryption) error {
+func (tk *ThresholdPublicKey) makeVerificationBeforeCombiningPartialDecryptions(shares []*PartialDecryption) error {
 	if len(shares) < tk.Threshold {
 		return errors.New("Threshold not meet")
 	}
@@ -62,7 +62,7 @@ func (tk *ThresholdKey) makeVerificationBeforeCombiningPartialDecryptions(shares
 	return nil
 }
 
-func (tk *ThresholdKey) updateLambda(share1, share2 *PartialDecryption, lambda *big.Int) *big.Int {
+func (tk *ThresholdPublicKey) 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)
@@ -70,7 +70,7 @@ func (tk *ThresholdKey) updateLambda(share1, share2 *PartialDecryption, lambda *
 
 // Evaluates lambda parameter for each decrypted share. See second figure in the
 // "Share combining" paragraph in [DJK 10], section 5.2.
-func (tk *ThresholdKey) computeLambda(share *PartialDecryption, shares []*PartialDecryption) *big.Int {
+func (tk *ThresholdPublicKey) computeLambda(share *PartialDecryption, shares []*PartialDecryption) *big.Int {
 	lambda := tk.delta()
 	for _, share2 := range shares {
 		if share2.Id != share.Id {
@@ -90,14 +90,14 @@ func (tk *ThresholdKey) computeLambda(share *PartialDecryption, shares []*Partia
 // following property of modulo:
 // (AB) mod C = (A mod C * B mod C) mod C
 // Note, we need to combine coefficients into single c'.
-func (tk *ThresholdKey) updateCprime(cprime, lambda *big.Int, share *PartialDecryption) *big.Int {
+func (tk *ThresholdPublicKey) updateCprime(cprime, lambda *big.Int, share *PartialDecryption) *big.Int {
 	twoLambda := new(big.Int).Mul(TWO, lambda)
 	ret := tk.exp(share.Decryption, twoLambda, tk.GetNSquare())
 	ret = new(big.Int).Mul(cprime, ret)
 	return new(big.Int).Mod(ret, tk.GetNSquare())
 }
 
-func (tk *ThresholdKey) exp(a, b, c *big.Int) *big.Int {
+func (tk *ThresholdPublicKey) exp(a, b, c *big.Int) *big.Int {
 	if b.Cmp(ZERO) == -1 {
 		ret := new(big.Int).Exp(a, new(big.Int).Neg(b), c)
 		return new(big.Int).ModInverse(ret, c)
@@ -108,7 +108,7 @@ func (tk *ThresholdKey) exp(a, b, c *big.Int) *big.Int {
 // Executes the last step of message decryption. Takes `cprime` value computed
 // from valid shares provided by decryption servers and multiplies this value
 // by `combineSharesContant` which is specific to the given public `ThresholdKey`.
-func (tk *ThresholdKey) computeDecryption(cprime *big.Int) *big.Int {
+func (tk *ThresholdPublicKey) computeDecryption(cprime *big.Int) *big.Int {
 	l := L(cprime, tk.N)
 	return new(big.Int).Mod(new(big.Int).Mul(tk.combineSharesConstant(), l), tk.N)
 }
@@ -117,7 +117,7 @@ func (tk *ThresholdKey) computeDecryption(cprime *big.Int) *big.Int {
 // decrypted message.
 // This function does not verify zero knowledge proofs. Returned message can be
 // incorrectly decrypted if an adversary corrupted partial decryption.
-func (tk *ThresholdKey) CombinePartialDecryptions(shares []*PartialDecryption) (*big.Int, error) {
+func (tk *ThresholdPublicKey) CombinePartialDecryptions(shares []*PartialDecryption) (*big.Int, error) {
 	if err := tk.makeVerificationBeforeCombiningPartialDecryptions(shares); err != nil {
 		return nil, err
 	}
@@ -135,7 +135,7 @@ func (tk *ThresholdKey) CombinePartialDecryptions(shares []*PartialDecryption) (
 // decrypted message.
 // Function verifies zero knowledge proofs and filters out all shares that failed
 // verification.
-func (tk *ThresholdKey) CombinePartialDecryptionsZKP(shares []*PartialDecryptionZKP) (*big.Int, error) {
+func (tk *ThresholdPublicKey) CombinePartialDecryptionsZKP(shares []*PartialDecryptionZKP) (*big.Int, error) {
 	ret := make([]*PartialDecryption, 0)
 	for _, share := range shares {
 		if share.Verify() {
@@ -149,7 +149,7 @@ func (tk *ThresholdKey) CombinePartialDecryptionsZKP(shares []*PartialDecryption
 // It verifies all the zero-knoledge proofs, the value of the encrypted
 // and decrypted message. The method returns `nil` if everything is fine.
 // Otherwise, it returns an explicative message.
-func (tk *ThresholdKey) VerifyDecryption(encryptedMessage, decryptedMessage *big.Int, shares []*PartialDecryptionZKP) error {
+func (tk *ThresholdPublicKey) VerifyDecryption(encryptedMessage, decryptedMessage *big.Int, shares []*PartialDecryptionZKP) error {
 	for _, share := range shares {
 		if share.C.Cmp(encryptedMessage) != 0 {
 			return errors.New("The encrypted message is not the same than the one in the shares")
@@ -170,7 +170,7 @@ func (tk *ThresholdKey) VerifyDecryption(encryptedMessage, decryptedMessage *big
 // `Id` is the unique identifier of a decryption server and `Share` is a secret
 // share generated from hiding polynomial and is used for a partial share decryption.
 type ThresholdPrivateKey struct {
-	ThresholdKey
+	ThresholdPublicKey
 	Id    int
 	Share *big.Int
 }
@@ -193,8 +193,8 @@ func (tpk *ThresholdPrivateKey) copyVi() []*big.Int {
 	return ret
 }
 
-func (tpk *ThresholdPrivateKey) getThresholdKey() *ThresholdKey {
-	ret := new(ThresholdKey)
+func (tpk *ThresholdPrivateKey) getThresholdKey() *ThresholdPublicKey {
+	ret := new(ThresholdPublicKey)
 	ret.Threshold = tpk.Threshold
 	ret.TotalNumberOfDecryptionServers = tpk.TotalNumberOfDecryptionServers
 	ret.V = new(big.Int).Add(tpk.V, big.NewInt(0))
@@ -325,10 +325,10 @@ type PartialDecryption struct {
 // - Compare ZKP hash with the one just computed
 type PartialDecryptionZKP struct {
 	PartialDecryption
-	Key *ThresholdKey // the public key used to encrypt
-	E   *big.Int      // the challenge
-	Z   *big.Int      // the value needed to check to verify the decryption
-	C   *big.Int      // the input cypher text
+	Key *ThresholdPublicKey // the public key used to encrypt
+	E   *big.Int            // the challenge
+	Z   *big.Int            // the value needed to check to verify the decryption
+	C   *big.Int            // the input cypher text
 }
 
 func (pd *PartialDecryptionZKP) verifyPart1() *big.Int {

thresholdkey_test.go

@@ -17,7 +17,7 @@ func getThresholdPrivateKey() *ThresholdPrivateKey {
 }
 
 func TestDelta(t *testing.T) {
-	tk := new(ThresholdKey)
+	tk := new(ThresholdPublicKey)
 	tk.TotalNumberOfDecryptionServers = 6
 	if delta := tk.delta(); 720 != n(delta) {
 		t.Error("Delta is not 720 but", delta)
@@ -25,7 +25,7 @@ func TestDelta(t *testing.T) {
 }
 
 func TestCombineSharesConstant(t *testing.T) {
-	tk := new(ThresholdKey)
+	tk := new(ThresholdPublicKey)
 	tk.N = big.NewInt(101 * 103)
 	tk.TotalNumberOfDecryptionServers = 6
 
@@ -84,7 +84,7 @@ func TestDecryptWithThresholdKey(t *testing.T) {
 
 func TestVerifyPart1(t *testing.T) {
 	pd := new(PartialDecryptionZKP)
-	pd.Key = new(ThresholdKey)
+	pd.Key = new(ThresholdPublicKey)
 	pd.Key.N = b(131)
 	pd.Decryption = b(101)
 	pd.C = b(99)
@@ -98,7 +98,7 @@ func TestVerifyPart1(t *testing.T) {
 
 func TestVerifyPart2(t *testing.T) {
 	pd := new(PartialDecryptionZKP)
-	pd.Key = new(ThresholdKey)
+	pd.Key = new(ThresholdPublicKey)
 	pd.Id = 1
 	pd.Key.Vi = []*big.Int{b(77), b(67)} // vi is 67
 	pd.Key.N = b(131)
@@ -127,7 +127,7 @@ func TestDecryptAndProduceZNP(t *testing.T) {
 }
 
 func TestMakeVerificationBeforeCombiningPartialDecryptions(t *testing.T) {
-	tk := new(ThresholdKey)
+	tk := new(ThresholdPublicKey)
 	tk.Threshold = 2
 	if tk.makeVerificationBeforeCombiningPartialDecryptions([]*PartialDecryption{}) == nil {
 		t.Fail()
@@ -144,7 +144,7 @@ func TestMakeVerificationBeforeCombiningPartialDecryptions(t *testing.T) {
 }
 
 func TestUpdateLambda(t *testing.T) {
-	tk := new(ThresholdKey)
+	tk := new(ThresholdPublicKey)
 	lambda := b(11)
 	share1 := &PartialDecryption{3, b(5)}
 	share2 := &PartialDecryption{7, b(3)}
@@ -155,7 +155,7 @@ func TestUpdateLambda(t *testing.T) {
 }
 
 func TestupdateCprime(t *testing.T) {
-	tk := new(ThresholdKey)
+	tk := new(ThresholdPublicKey)
 	tk.N = b(99)
 	cprime := b(77)
 	lambda := b(52)
@@ -238,7 +238,7 @@ func TestDecryption(t *testing.T) {
 	// test the correct decryption of '100'.
 	share1 := &PartialDecryption{1, b(384111638639)}
 	share2 := &PartialDecryption{2, b(235243761043)}
-	tk := new(ThresholdKey)
+	tk := new(ThresholdPublicKey)
 	tk.Threshold = 2
 	tk.TotalNumberOfDecryptionServers = 2
 	tk.N = b(637753)
@@ -325,7 +325,7 @@ func TestVerifyDecryption(t *testing.T) {
 	tkh := GetThresholdKeyGenerator(10, 2, 2, rand.Reader)
 	tpks, err := tkh.Generate()
 
-	pk := &tpks[0].ThresholdKey
+	pk := &tpks[0].ThresholdPublicKey
 	if err != nil {
 		t.Error(err)
 	}