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crypto/secret/key.go

@@ -0,0 +1,107 @@
+package secret
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/onsonr/hway/crypto"
+	"github.com/onsonr/hway/crypto/accumulator"
+	"github.com/onsonr/hway/crypto/core/curves"
+)
+
+// PrimaryKey is the secret key for the BLS scheme
+type PrimaryKey struct {
+	*accumulator.SecretKey
+}
+
+// Element is the element for the BLS scheme
+type Element = accumulator.Element
+
+// NewKey creates a new primary key
+func NewKey(propertyKey string, pubKey crypto.PublicKey) (*PrimaryKey, error) {
+	// Concatenate the controller's public key and the property key
+	input := append(pubKey.Bytes(), []byte(propertyKey)...)
+	hash := []byte(input)
+
+	// Use the hash as the seed for the secret key
+	curve := curves.BLS12381(&curves.PointBls12381G1{})
+	key, err := new(accumulator.SecretKey).New(curve, hash[:])
+	if err != nil {
+		return nil, errors.Join(err, fmt.Errorf("failed to create secret key"))
+	}
+	return &PrimaryKey{SecretKey: key}, nil
+}
+
+// CreateAccumulator creates a new accumulator
+func (s *PrimaryKey) CreateAccumulator(values ...string) (*accumulator.Accumulator, error) {
+	curve := curves.BLS12381(&curves.PointBls12381G1{})
+	acc, err := new(accumulator.Accumulator).New(curve)
+	if err != nil {
+		return nil, err
+	}
+	fin, _, err := acc.Update(s.SecretKey, convertValuesToElements(values), nil)
+	if err != nil {
+		return nil, err
+	}
+	return fin, nil
+}
+
+// CreateWitness creates a witness for the accumulator for a given value
+func (s *PrimaryKey) CreateWitness(acc *accumulator.Accumulator, value string) (*accumulator.MembershipWitness, error) {
+	curve := curves.BLS12381(&curves.PointBls12381G1{})
+	element := curve.Scalar.Hash([]byte(value))
+	mw, err := new(accumulator.MembershipWitness).New(element, acc, s.SecretKey)
+	if err != nil {
+		return nil, err
+	}
+	return mw, nil
+}
+
+// ProveMembership proves that a value is a member of the accumulator
+func (s *PrimaryKey) VerifyWitness(acc *accumulator.Accumulator, witness *accumulator.MembershipWitness) error {
+	return witness.Verify(s.PublicKey(), acc)
+}
+
+// PublicKey returns the public key for the secret key
+func (s *PrimaryKey) PublicKey() *accumulator.PublicKey {
+	curve := curves.BLS12381(&curves.PointBls12381G1{})
+	pk, err := s.GetPublicKey(curve)
+	if err != nil {
+		panic(err)
+	}
+	return pk
+}
+
+// UpdateAccumulator updates the accumulator with new values
+func (s *PrimaryKey) UpdateAccumulator(acc *accumulator.Accumulator, addValues, removeValues []string) (*accumulator.Accumulator, error) {
+	acc, _, err := acc.Update(s.SecretKey, convertValuesToElements(addValues), convertValuesToElements(removeValues))
+	if err != nil {
+		return nil, err
+	}
+	return acc, nil
+}
+
+// MarshalAccumulator takes a *accumulator.Accumulator and returns a byte slice
+func MarshalAccumulator(acc *accumulator.Accumulator) ([]byte, error) {
+	return acc.MarshalBinary()
+}
+
+// UnmarshalAccumulator takes a byte slice and returns a *accumulator.Accumulator
+func UnmarshalAccumulator(data []byte) (*accumulator.Accumulator, error) {
+	acc := new(accumulator.Accumulator)
+	err := acc.UnmarshalBinary(data)
+	if err != nil {
+		return nil, err
+	}
+	return acc, nil
+}
+
+func convertValuesToElements(values []string) []accumulator.Element {
+	curve := curves.BLS12381(&curves.PointBls12381G1{})
+	elements := []accumulator.Element{}
+	for _, value := range values {
+		element := curve.Scalar.Hash([]byte(value))
+		elements = append(elements, element)
+	}
+	return elements
+}