good progress on did:key, x25519

interfaces.go

@@ -14,6 +14,8 @@ type DID interface {
 
 	Document() (Document, error)
 	String() string // return the full DID URL, with path, query, fragment
+
+	Equal(DID) bool
 }
 
 // Document is the interface for a DID document. It represents the "resolved" state of a DID.
@@ -34,25 +36,25 @@ type Document interface {
 
 	// Authentication defines how the DID is able to authenticate, for purposes such as logging into a website
 	// or engaging in any sort of challenge-response protocol.
-	Authentication() []VerificationMethod
+	Authentication() []VerificationMethodSignature
 
 	// Assertion specifies how the DID subject is expected to express claims, such as for the purposes of issuing
 	// a Verifiable Credential.
 	// See https://www.w3.org/TR/vc-data-model/
-	Assertion() []VerificationMethod
+	Assertion() []VerificationMethodSignature
 
 	// KeyAgreement specifies how an entity can generate encryption material in order to transmit confidential
 	// information intended for the DID subject, such as for the purposes of establishing a secure communication channel
 	// with the recipient.
-	KeyAgreement() []VerificationMethod
+	KeyAgreement() []VerificationMethodKeyAgreement
 
 	// CapabilityInvocation specifies a verification method that might be used by the DID subject to invoke a
 	// cryptographic capability, such as the authorization to update the DID Document.
-	CapabilityInvocation() []VerificationMethod
+	CapabilityInvocation() []VerificationMethodSignature
 
 	// CapabilityDelegation specifies a mechanism that might be used by the DID subject to delegate a cryptographic
 	// capability to another party, such as delegating the authority to access a specific HTTP API to a subordinate.
-	CapabilityDelegation() []VerificationMethod
+	CapabilityDelegation() []VerificationMethodSignature
 
 	// TODO: Service
 	// https://www.w3.org/TR/did-extensions-properties/#service-types
@@ -77,7 +79,22 @@ type VerificationMethod interface {
 
 	// JsonLdContext reports the JSON-LD context definition required for this verification method.
 	JsonLdContext() string
+}
+
+// VerificationMethodSignature is a VerificationMethod implementing signature verification.
+// It can be used for Authentication, Assertion, CapabilityInvocation, CapabilityDelegation
+// in a Document.
+type VerificationMethodSignature interface {
+	VerificationMethod
 
 	// Verify checks that 'sig' is a valid signature of 'data'.
 	Verify(data []byte, sig []byte) bool
 }
+
+// VerificationMethodKeyAgreement is a VerificationMethod implementing a shared key agreement.
+// It can be used for KeyAgreement in a Document.
+type VerificationMethodKeyAgreement interface {
+	VerificationMethod
+
+	// TODO: function for key agreement
+}