some refacto and added tests

Signed-off-by: bytemare <[email protected]>

commitment.go

@@ -6,7 +6,6 @@
 // LICENSE file in the root directory of this source tree or at
 // https://spdx.org/licenses/MIT.html
 
-// Package commitment defines the FROST Signer commitment.
 package frost
 
 import (
@@ -238,7 +237,7 @@ func (c CommitmentList) groupCommitment(bf BindingFactors) *group.Element {
 }
 
 func (c *Configuration) isSignerRegistered(sid uint64) bool {
-	for _, peer := range c.SignerPublicKeys {
+	for _, peer := range c.SignerPublicKeyShares {
 		if peer.ID == sid {
 			return true
 		}
@@ -249,6 +248,12 @@ func (c *Configuration) isSignerRegistered(sid uint64) bool {
 
 // ValidateCommitment returns an error if the commitment is not valid.
 func (c *Configuration) ValidateCommitment(commitment *Commitment) error {
+	if !c.verified || !c.keysVerified {
+		if err := c.Init(); err != nil {
+			return err
+		}
+	}
+
 	if commitment == nil {
 		return fmt.Errorf("the commitment list has a nil commitment")
 	}
@@ -322,6 +327,12 @@ func (c *Configuration) validateCommitmentListLength(commitments CommitmentList)
 // - no duplicated in signer identifiers
 // - all commitment signer identifiers are registered in the configuration
 func (c *Configuration) ValidateCommitmentList(commitments CommitmentList) error {
+	if !c.verified || !c.keysVerified {
+		if err := c.Init(); err != nil {
+			return err
+		}
+	}
+
 	if err := c.validateCommitmentListLength(commitments); err != nil {
 		return err
 	}

coordinator.go

@@ -42,6 +42,12 @@ func (c *Configuration) AggregateSignatures(
 	commitments CommitmentList,
 	verify bool,
 ) (*Signature, error) {
+	if !c.verified || !c.keysVerified {
+		if err := c.Init(); err != nil {
+			return nil, err
+		}
+	}
+
 	groupCommitment, bindingFactors, participants, err := c.prepareSignatureShareVerification(message, commitments)
 	if err != nil {
 		return nil, err
@@ -89,6 +95,12 @@ func (c *Configuration) VerifySignatureShare(
 	message []byte,
 	commitments CommitmentList,
 ) error {
+	if !c.verified || !c.keysVerified {
+		if err := c.Init(); err != nil {
+			return err
+		}
+	}
+
 	groupCommitment, bindingFactors, participants, err := c.prepareSignatureShareVerification(message, commitments)
 	if err != nil {
 		return err
@@ -100,12 +112,6 @@ func (c *Configuration) VerifySignatureShare(
 func (c *Configuration) prepareSignatureShareVerification(message []byte,
 	commitments CommitmentList,
 ) (*group.Element, BindingFactors, []*group.Scalar, error) {
-	if !c.verified {
-		if err := c.verify(); err != nil {
-			return nil, nil, nil, err
-		}
-	}
-
 	commitments.Sort()
 
 	// Validate general consistency of the commitment list.

encoding.go

@@ -68,16 +68,16 @@ func encodedLength(encID byte, g group.Group, other ...uint64) uint64 {
 func (c *Configuration) Encode() []byte {
 	g := group.Group(c.Ciphersuite)
 	pksLen := encodedLength(encPubKeyShare, g, c.Threshold*uint64(g.ElementLength()))
-	size := encodedLength(encConf, g, uint64(len(c.SignerPublicKeys))*pksLen)
+	size := encodedLength(encConf, g, uint64(len(c.SignerPublicKeyShares))*pksLen)
 	out := make([]byte, 25, size)
 	out[0] = byte(g)
 	binary.LittleEndian.PutUint64(out[1:9], c.Threshold)
 	binary.LittleEndian.PutUint64(out[9:17], c.MaxSigners)
-	binary.LittleEndian.PutUint64(out[17:25], uint64(len(c.SignerPublicKeys)))
+	binary.LittleEndian.PutUint64(out[17:25], uint64(len(c.SignerPublicKeyShares)))
 
 	out = append(out, c.GroupPublicKey.Encode()...)
 
-	for _, pk := range c.SignerPublicKeys {
+	for _, pk := range c.SignerPublicKeyShares {
 		out = append(out, pk.Encode()...)
 	}
 
@@ -106,7 +106,7 @@ func (c *Configuration) decodeHeader(data []byte) (*confHeader, error) {
 	pksLen := encodedLength(encPubKeyShare, g, t*uint64(g.ElementLength()))
 	length := encodedLength(encConf, g, nPks*pksLen)
 
-	if t > n {
+	if t == 0 || t > n {
 		return nil, errInvalidConfigEncoding
 	}
 
@@ -135,12 +135,15 @@ func (c *Configuration) decode(header *confHeader, data []byte) error {
 	pks := make([]*PublicKeyShare, header.nPks)
 
 	conf := &Configuration{
-		Ciphersuite:      Ciphersuite(header.g),
-		Threshold:        header.t,
-		MaxSigners:       header.n,
-		GroupPublicKey:   gpk,
-		SignerPublicKeys: pks,
-		group:            header.g,
+		Ciphersuite:           Ciphersuite(header.g),
+		Threshold:             header.t,
+		MaxSigners:            header.n,
+		GroupPublicKey:        gpk,
+		SignerPublicKeyShares: pks,
+	}
+
+	if err := conf.verifyConfiguration(); err != nil {
+		return err
 	}
 
 	for j := range header.nPks {
@@ -149,25 +152,22 @@ func (c *Configuration) decode(header *confHeader, data []byte) error {
 			return fmt.Errorf("could not decode signer public key share for signer %d: %w", j, err)
 		}
 
-		if err := conf.validatePublicKeyShare(pk); err != nil {
-			return err
-		}
-
 		offset += pksLen
 		pks[j] = pk
 	}
 
-	if err := conf.verify(); err != nil {
+	if err := conf.verifySignerPublicKeyShares(); err != nil {
 		return err
 	}
 
 	c.Ciphersuite = conf.Ciphersuite
 	c.Threshold = conf.Threshold
 	c.MaxSigners = conf.MaxSigners
 	c.GroupPublicKey = gpk
-	c.SignerPublicKeys = pks
+	c.SignerPublicKeyShares = pks
 	c.group = group.Group(conf.Ciphersuite)
 	c.verified = true
+	c.keysVerified = true
 
 	return nil
 }

examples_test.go

@@ -39,11 +39,11 @@ func Example_signer() {
 
 	// This is how to set up the Configuration for FROST, the same for every signer and the coordinator.
 	configuration := &frost.Configuration{
-		Ciphersuite:      ciphersuite,
-		Threshold:        threshold,
-		MaxSigners:       maxSigners,
-		GroupPublicKey:   groupPublicKey,
-		SignerPublicKeys: publicKeyShares,
+		Ciphersuite:           ciphersuite,
+		Threshold:             threshold,
+		MaxSigners:            maxSigners,
+		GroupPublicKey:        groupPublicKey,
+		SignerPublicKeyShares: publicKeyShares,
 	}
 
 	if err := configuration.Init(); err != nil {
@@ -126,11 +126,11 @@ func Example_coordinator() {
 
 	// This is how to set up the Configuration for FROST, the same for every signer and the coordinator.
 	configuration := &frost.Configuration{
-		Ciphersuite:      ciphersuite,
-		Threshold:        threshold,
-		MaxSigners:       maxSigners,
-		GroupPublicKey:   groupPublicKey,
-		SignerPublicKeys: publicKeyShares,
+		Ciphersuite:           ciphersuite,
+		Threshold:             threshold,
+		MaxSigners:            maxSigners,
+		GroupPublicKey:        groupPublicKey,
+		SignerPublicKeyShares: publicKeyShares,
 	}
 
 	if err := configuration.Init(); err != nil {