add support for P256Key2021

verifications/p256/key2021.go

@@ -0,0 +1,114 @@
+package p256vm
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+
+	"github.com/mr-tron/base58"
+
+	"github.com/INFURA/go-did"
+	"github.com/INFURA/go-did/crypto"
+	"github.com/INFURA/go-did/crypto/p256"
+)
+
+// Specification: missing
+
+const (
+	JsonLdContext2021 = "https://w3id.org/security/suites/multikey-2021/v1"
+	Type2021          = "P256Key2021"
+)
+
+var _ did.VerificationMethodSignature = &Key2021{}
+var _ did.VerificationMethodKeyAgreement = &Key2021{}
+
+type Key2021 struct {
+	id         string
+	pubkey     *p256.PublicKey
+	controller string
+}
+
+func NewKey2021(id string, pubkey *p256.PublicKey, controller did.DID) *Key2021 {
+	return &Key2021{
+		id:         id,
+		pubkey:     pubkey,
+		controller: controller.String(),
+	}
+}
+
+func (m Key2021) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		ID              string `json:"id"`
+		Type            string `json:"type"`
+		Controller      string `json:"controller"`
+		PublicKeyBase58 string `json:"publicKeyBase58"`
+	}{
+		ID:              m.ID(),
+		Type:            m.Type(),
+		Controller:      m.Controller(),
+		PublicKeyBase58: base58.Encode(m.pubkey.ToBytes()),
+	})
+}
+
+func (m *Key2021) UnmarshalJSON(bytes []byte) error {
+	aux := struct {
+		ID              string `json:"id"`
+		Type            string `json:"type"`
+		Controller      string `json:"controller"`
+		PublicKeyBase58 string `json:"publicKeyBase58"`
+	}{}
+	err := json.Unmarshal(bytes, &aux)
+	if err != nil {
+		return err
+	}
+	if aux.Type != m.Type() {
+		return errors.New("invalid type")
+	}
+	m.id = aux.ID
+	if len(m.id) == 0 {
+		return errors.New("invalid id")
+	}
+	m.controller = aux.Controller
+	if !did.HasValidDIDSyntax(m.controller) {
+		return errors.New("invalid controller")
+	}
+
+	pubBytes, err := base58.Decode(aux.PublicKeyBase58)
+	if err != nil {
+		return fmt.Errorf("invalid publicKeyBase58: %w", err)
+	}
+	m.pubkey, err = p256.PublicKeyFromBytes(pubBytes)
+	if err != nil {
+		return fmt.Errorf("invalid publicKeyBase58: %w", err)
+	}
+
+	return nil
+}
+
+func (m Key2021) ID() string {
+	return m.id
+}
+
+func (m Key2021) Type() string {
+	return Type2021
+}
+
+func (m Key2021) Controller() string {
+	return m.controller
+}
+
+func (m Key2021) JsonLdContext() string {
+	return JsonLdContext2021
+}
+
+func (m Key2021) Verify(data []byte, sig []byte) (bool, error) {
+	return m.pubkey.VerifyBytes(data, sig), nil
+}
+
+func (m Key2021) PrivateKeyIsCompatible(local crypto.PrivateKeyKeyExchange) bool {
+	return local.PublicKeyIsCompatible(m.pubkey)
+}
+
+func (m Key2021) KeyExchange(local crypto.PrivateKeyKeyExchange) ([]byte, error) {
+	return local.KeyExchange(m.pubkey)
+}

verifications/p256/key2021_test.go

@@ -0,0 +1,27 @@
+package p256vm_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	p256vm "github.com/INFURA/go-did/verifications/p256"
+)
+
+func TestJsonRoundTrip(t *testing.T) {
+	data := `{
+          "id": "did:key:zDnaeTiq1PdzvZXUaMdezchcMJQpBdH2VN4pgrrEhMCCbmwSb#zDnaeTiq1PdzvZXUaMdezchcMJQpBdH2VN4pgrrEhMCCbmwSb",
+          "type": "P256Key2021",
+          "controller": "did:key:zDnaeTiq1PdzvZXUaMdezchcMJQpBdH2VN4pgrrEhMCCbmwSb",
+          "publicKeyBase58": "ekVhkcBFq3w7jULLkBVye6PwaTuMbhJYuzwFnNcgQAPV"
+        }`
+
+	var mk p256vm.Key2021
+	err := json.Unmarshal([]byte(data), &mk)
+	require.NoError(t, err)
+
+	bytes, err := json.Marshal(mk)
+	require.NoError(t, err)
+	require.JSONEq(t, data, string(bytes))
+}