WIP: Add did

did/did.go

@@ -0,0 +1,230 @@
+package did
+
+import (
+	"crypto/rand"
+	"errors"
+	"strings"
+	"time"
+
+	"github.com/mr-tron/base58"
+	"github.com/multiformats/go-multibase"
+	"golang.org/x/crypto/ed25519"
+)
+
+const didPrefix = "did:ipid:"
+const didContext = "bafyreict2igxeqinf4uyg26ubff2vginv7hiz3dxiiwb77vwyr3c5jd3rq"
+
+type DIDDocument struct {
+	Context        DIDContext        `json:"@context"`
+	Authentication Authentication    `json:"authentication"`
+	Created        string            `json:"created"`
+	ID             string            `json:"id"`
+	Previous       map[string]string `json:"previous"`
+	Proof          map[string]string `json:"proof"`
+	PublicKey      []PublicKey       `json:"publicKey"`
+	Signature      Signature         `json:"signature"`
+	Updated        string            `json:"updated"`
+}
+
+type DIDContext struct {
+	Version            int                    `json:"@version"`
+	Authentication     IDType                 `json:"authentication"`
+	Created            DateTimeType           `json:"created"`
+	Cryptosuite        string                 `json:"cryptosuite"`
+	DC                 string                 `json:"dc"`
+	ID                 string                 `json:"id"`
+	Proof              string                 `json:"proof"`
+	ProofPurpose       string                 `json:"proofPurpose"`
+	ProofValue         string                 `json:"proofValue"`
+	PublicKeyMultibase PublicKeyMultibaseType `json:"publicKeyMultibase"`
+	SEC                string                 `json:"sec"`
+	Type               string                 `json:"type"`
+	Updated            DateTimeType           `json:"updated"`
+	VerificationMethod IDType                 `json:"verificationMethod"`
+	XSD                string                 `json:"xsd"`
+}
+
+type IDType struct {
+	ID   string `json:"@id"`
+	Type string `json:"@type"`
+}
+
+type DateTimeType struct {
+	ID   string `json:"@id"`
+	Type string `json:"@type"`
+}
+
+type PublicKeyMultibaseType struct {
+	Container string `json:"@container"`
+	ID        string `json:"@id"`
+	Type      string `json:"@type"`
+}
+
+type Authentication struct {
+	Type      string   `json:"type"`
+	PublicKey []string `json:"publicKey"`
+}
+
+type PublicKey struct {
+	Curve              string `json:"curve"`
+	Expires            string `json:"expires,omitempty"`
+	PublicKeyMultibase string `json:"publicKeyMultibase"`
+	Type               string `json:"type"`
+	Status             string `json:"status,omitempty"`
+}
+
+type Signature struct {
+	Created        string            `json:"created"`
+	Creator        string            `json:"creator"`
+	Message        map[string]string `json:"message"`
+	SignatureValue string            `json:"signatureValue"`
+	Type           string            `json:"type"`
+}
+
+func New() (*DIDDocument, ed25519.PrivateKey, error) {
+	publicKey, privateKey, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	did := "did:key:" + base58.Encode(publicKey)
+
+	doc := &DIDDocument{
+		Context: DIDContext{
+			Version: 2,
+			Authentication: IDType{
+				ID:   "sec:authentication",
+				Type: "@id",
+			},
+			Created: DateTimeType{
+				ID:   "dc:created",
+				Type: "xsd:dateTime",
+			},
+			Cryptosuite:  "sec:cryptosuite",
+			DC:           "http://purl.org/dc/terms/",
+			ID:           "@id",
+			Proof:        "sec:proof",
+			ProofPurpose: "sec:proofPurpose",
+			ProofValue:   "sec:proofValue",
+			PublicKeyMultibase: PublicKeyMultibaseType{
+				Container: "@set",
+				ID:        "sec:publicKeyMultibase",
+				Type:      "@id",
+			},
+			SEC:  "https://w3id.org/security#",
+			Type: "@type",
+			Updated: DateTimeType{
+				ID:   "dc:updated",
+				Type: "xsd:dateTime",
+			},
+			VerificationMethod: IDType{
+				ID:   "sec:verificationMethod",
+				Type: "@id",
+			},
+			XSD: "http://www.w3.org/2001/XMLSchema#",
+		},
+		Authentication: Authentication{
+			Type:      "EdDsaSASignatureAuthentication2018",
+			PublicKey: []string{did},
+		},
+		Created: "2018-12-01T03:00:00Z",
+		ID:      did,
+		Previous: map[string]string{
+			"/": "zdpuB1oR3vjYmkDc9ALfY7o6hSt1Hrg2ApXaYAFyiAW5E4NJP",
+		},
+		Proof: map[string]string{
+			"/": "z43AaGF42R2DXsU65bNnHRCypLPr9sg6D7CUws5raiqATVaB1jj",
+		},
+		PublicKey: []PublicKey{
+			{
+				Curve:              "ed25519",
+				PublicKeyMultibase: base58.Encode(publicKey),
+				Type:               "EdDsaPublicKey",
+				Status:             "revoked",
+			},
+			{
+				Curve:              "ed25519",
+				Expires:            time.Now().Add(365 * 24 * time.Hour).Format(time.RFC3339),
+				PublicKeyMultibase: base58.Encode(publicKey),
+				Type:               "EdDsaPublicKey",
+			},
+		},
+		Signature: Signature{
+			Created:        "2018-12-01T03:00:04Z",
+			Creator:        did + "/publicKey/1",
+			Message:        map[string]string{"/": "zdpuAyvreXzQHqwv3rL8MaVPjNJjpLLa5Du3HcbpQL41XS35G"},
+			SignatureValue: base58.Encode(ed25519.Sign(privateKey, []byte(did))),
+			Type:           "ed25519Signature2018",
+		},
+		Updated: "2018-12-01T03:00:04Z",
+	}
+
+	return doc, privateKey, nil
+}
+
+// Adds a new public key to the DID Document.
+func (doc *DIDDocument) AddPublicKey(pubKey ed25519.PublicKey, isRevoked bool) {
+	pk := PublicKey{
+		Curve:              "ed25519",
+		PublicKeyMultibase: base58.Encode(pubKey),
+		Type:               "EdDsaPublicKey",
+	}
+	if isRevoked {
+		pk.Status = "revoked"
+	} else {
+		pk.Expires = time.Now().Add(365 * 24 * time.Hour).Format(time.RFC3339)
+	}
+	doc.PublicKey = append(doc.PublicKey, pk)
+}
+
+// Signs a message with the private key, returning the signature.
+func (doc *DIDDocument) Sign(privateKey ed25519.PrivateKey, message []byte) (string, error) {
+	if len(privateKey) == 0 || len(message) == 0 {
+		return "", errors.New("empty private key or message")
+	}
+	signature := ed25519.Sign(privateKey, message)
+	return base58.Encode(signature), nil
+}
+
+func (doc *DIDDocument) VerifyProof(proof string, message []byte) bool {
+	signature, err := base58.Decode(proof)
+	if err != nil {
+		return false
+	}
+
+	for _, pk := range doc.PublicKey {
+		keyType := extractKeyType(pk.PublicKeyMultibase)
+		if keyType == "ed25519" {
+			pubKey, err := base58.Decode(pk.PublicKeyMultibase)
+			if err != nil {
+				continue
+			}
+			if ed25519.Verify(pubKey, message, signature) {
+				return true
+			}
+		}
+		// Future: Add conditions for other key types
+	}
+	return false
+}
+func extractKeyType(did string) string {
+	// First, strip off the "did:key:" prefix
+	if !strings.HasPrefix(did, didPrefix) {
+		return ""
+	}
+	mbValue := did[len(didPrefix):]
+
+	// Decode the multibase value
+	_, decodedBytes, err := multibase.Decode(mbValue)
+	if err != nil {
+		return ""
+	}
+
+	// Check the multicodec prefix
+	if len(decodedBytes) > 2 && decodedBytes[0] == 0xed && decodedBytes[1] == 0x01 {
+		return "ed25519"
+	}
+
+	// Return an empty string for unsupported or unrecognized key types
+	return ""
+}