refactor: add JSON-LD @context in attribute-based signatures

irma_signature.go

@@ -11,18 +11,25 @@ import (
 	"github.com/privacybydesign/gabi/big"
 )
 
+const SignedMessageLDContext = "https://irma.app/ld/signature/v2"
+
 // SignedMessage is a message signed with an attribute-based signature
 // The 'realnonce' will be calculated as: SigRequest.GetNonce() = ASN1(nonce, SHA256(message), timestampSignature)
 type SignedMessage struct {
+	LDContext string                    `json:"@context"`
 	Signature gabi.ProofList            `json:"signature"`
 	Indices   DisclosedAttributeIndices `json:"indices"`
 	Nonce     *big.Int                  `json:"nonce"`
 	Context   *big.Int                  `json:"context"`
 	Message   string                    `json:"message"`
 	Timestamp *atum.Timestamp           `json:"timestamp"`
+}
 
-	// Message version. Current version is 2.
-	Version int `json:"v,omitempty"`
+func (sm *SignedMessage) Version() int {
+	if sm.LDContext == "" {
+		return 1
+	}
+	return 2
 }
 
 func (sm *SignedMessage) GetNonce() *big.Int {

irmaclient/logs.go

@@ -20,10 +20,10 @@ type LogEntry struct {
 	request irma.SessionRequest // cached parsed version of Request; get with LogEntry.SessionRequest()
 
 	// Session type-specific info
-	Removed          map[irma.CredentialTypeIdentifier][]irma.TranslatedString `json:",omitempty"` // In case of credential removal
-	SignedMessage    []byte                                                    `json:",omitempty"` // In case of signature sessions
-	Timestamp        *atum.Timestamp                                           `json:",omitempty"` // In case of signature sessions
-	SignatureVersion int                                                       `json:",omitempty"` // In case of signature sessions
+	Removed                map[irma.CredentialTypeIdentifier][]irma.TranslatedString `json:",omitempty"` // In case of credential removal
+	SignedMessage          []byte                                                    `json:",omitempty"` // In case of signature sessions
+	Timestamp              *atum.Timestamp                                           `json:",omitempty"` // In case of signature sessions
+	SignedMessageLDContext string                                                    `json:",omitempty"` // In case of signature sessions
 
 	IssueCommitment *irma.IssueCommitmentMessage `json:",omitempty"`
 	Disclosure      *irma.Disclosure             `json:",omitempty"`
@@ -106,12 +106,12 @@ func (entry *LogEntry) GetSignedMessage() (abs *irma.SignedMessage, err error) {
 	}
 	sigrequest := request.(*irma.SignatureRequest)
 	return &irma.SignedMessage{
+		LDContext: entry.SignedMessageLDContext,
 		Signature: entry.Disclosure.Proofs,
 		Nonce:     sigrequest.Nonce,
 		Context:   sigrequest.Context,
 		Message:   string(entry.SignedMessage),
 		Timestamp: entry.Timestamp,
-		Version:   entry.SignatureVersion,
 	}, nil
 }
 
@@ -135,7 +135,7 @@ func (session *session) createLogEntry(response interface{}) (*LogEntry, error)
 		request := session.request.(*irma.SignatureRequest)
 		entry.SignedMessage = []byte(request.Message)
 		entry.Timestamp = request.Timestamp
-		entry.SignatureVersion = 2
+		entry.SignedMessageLDContext = irma.SignedMessageLDContext
 
 		fallthrough
 	case irma.ActionDisclosing:

requests.go

@@ -433,13 +433,13 @@ func (sr *SignatureRequest) SignatureFromMessage(message interface{}) (*SignedMe
 	}
 
 	return &SignedMessage{
+		LDContext: SignedMessageLDContext,
 		Signature: signature.Proofs,
 		Indices:   signature.Indices,
 		Nonce:     sr.Nonce,
 		Context:   sr.Context,
 		Message:   sr.Message,
 		Timestamp: sr.Timestamp,
-		Version:   2,
 	}, nil
 }
 

timestamp.go

@@ -114,7 +114,7 @@ func (sm *SignedMessage) VerifyTimestamp(message string, conf *Configuration) er
 		}
 	}
 
-	bts, err := TimestampRequest(message, sigs, disclosed, sm.Version >= 2, conf)
+	bts, err := TimestampRequest(message, sigs, disclosed, sm.Version() >= 2, conf)
 	if err != nil {
 		return err
 	}