Create fingerprint() method and display its results

client/cli.go

@@ -808,6 +808,7 @@ func (c *cliClient) showIdentity() {
 		heading:      "Identity",
 		rows: []cliRow{
 			cliRow{cols: []string{"Server", terminalEscape(c.server, false)}},
+			cliRow{cols: []string{"Fingerprint", fmt.Sprintf("%d", c.fingerprint())}},
 			cliRow{cols: []string{"Public identity", fmt.Sprintf("%x", c.identityPublic[:])}},
 			cliRow{cols: []string{"Public key", fmt.Sprintf("%x", c.pub[:])}},
 			cliRow{cols: []string{"State file", terminalEscape(c.stateFilename, false)}},
@@ -1858,9 +1859,10 @@ func (c *cliClient) showContact(contact *Contact) {
 		rows: []cliRow{
 			cliRow{cols: []string{"Name", terminalEscape(contact.name, false)}},
 			cliRow{cols: []string{"Server", terminalEscape(contact.theirServer, false)}},
-			cliRow{cols: []string{"Generation", fmt.Sprintf("%d", contact.generation)}},
+			cliRow{cols: []string{"Fingerprint", fmt.Sprintf("%d", contact.fingerprint())}},
+			cliRow{cols: []string{"Public Identity key", fmt.Sprintf("%x", contact.theirIdentityPublic[:])}},
 			cliRow{cols: []string{"Public key", fmt.Sprintf("%x", contact.theirPub[:])}},
-			cliRow{cols: []string{"Identity key", fmt.Sprintf("%x", contact.theirIdentityPublic[:])}},
+			cliRow{cols: []string{"Generation", fmt.Sprintf("%d", contact.generation)}},
 			cliRow{cols: []string{"Client version", fmt.Sprintf("%d", contact.supportedVersion)}},
 		},
 	}

client/client.go

@@ -477,6 +477,15 @@ type Contact struct {
 	cliId cliId
 }
 
+func (contact *Contact) fingerprint() []byte {
+	if contact.isPending { return []byte{} }
+	return fingerprint(contact.theirPub[:],contact.theirIdentityPublic[:],nil)
+}
+
+func (c *client) fingerprint() []byte {
+	return fingerprint(c.pub[:],c.identityPublic[:],nil)
+}
+
 // Event represents a log entry. This does not apply to the global log, which
 // is quite chatty, but rather to significant events related to a given
 // contact. These events are surfaced in the UI and recorded in the statefile.

client/gui.go

@@ -1897,6 +1897,7 @@ func nameValuesLHS(entries []nvEntry) Grid {
 func (c *guiClient) identityUI() interface{} {
 	entries := nameValuesLHS([]nvEntry{
 		{"SERVER", c.server},
+		{"FINGERPRINT", fmt.Sprintf("%x", c.fingerprint())},
 		{"PUBLIC IDENTITY", fmt.Sprintf("%x", c.identityPublic[:])},
 		{"PUBLIC KEY", fmt.Sprintf("%x", c.pub[:])},
 		{"STATE FILE", c.stateFilename},
@@ -2048,6 +2049,13 @@ func (c *guiClient) identityUI() interface{} {
 	panic("unreachable")
 }
 
+func allBytesZero(bs []byte) bool {
+	for _,b := range bs {
+		if b != 0 { return false }
+	}
+	return true
+}
+
 func (c *guiClient) showContact(id uint64) interface{} {
 	contact := c.contacts[id]
 	if contact.isPending && len(contact.pandaKeyExchange) == 0 && len(contact.pandaResult) == 0 {
@@ -2058,13 +2066,18 @@ func (c *guiClient) showContact(id uint64) interface{} {
 	entries := []nvEntry{
 		{"NAME", ""},
 		{"SERVER", contact.theirServer},
-		{"PUBLIC IDENTITY", fmt.Sprintf("%x", contact.theirIdentityPublic[:])},
+		{"FINGERPRINT", fmt.Sprintf("%x", contact.fingerprint())},
+		{"PUBLIC IDENTITY KEY", fmt.Sprintf("%x", contact.theirIdentityPublic[:])},
 		{"PUBLIC KEY", fmt.Sprintf("%x", contact.theirPub[:])},
-		{"LAST DH", fmt.Sprintf("%x", contact.theirLastDHPublic[:])},
-		{"CURRENT DH", fmt.Sprintf("%x", contact.theirCurrentDHPublic[:])},
-		{"GROUP GENERATION", fmt.Sprintf("%d", contact.generation)},
-		{"CLIENT VERSION", fmt.Sprintf("%d", contact.supportedVersion)},
 	}
+	if ! allBytesZero(contact.theirLastDHPublic[:]) {
+		entries = append(entries,
+			nvEntry{"LAST DH", fmt.Sprintf("%x", contact.theirLastDHPublic[:])},
+			nvEntry{"CURRENT DH", fmt.Sprintf("%x", contact.theirCurrentDHPublic[:])} )
+	}
+	entries = append(entries,
+		nvEntry{"GROUP GENERATION", fmt.Sprintf("%d", contact.generation)},
+		nvEntry{"CLIENT VERSION", fmt.Sprintf("%d", contact.supportedVersion)} )
 
 	var pandaMessage string
 

client/network.go

@@ -153,6 +153,15 @@ func tooLarge(msg *queuedMessage) bool {
 	return len(messageBytes) > pond.MaxSerializedMessage
 }
 
+func fingerprint(a,b,c []byte) []byte {
+	sha := sha256.New()
+	sha.Write(a)
+	sha.Write(b)
+	digest := sha.Sum(c)
+	sha.Reset()
+	return digest
+}
+
 // processSigningRequest is run on the main goroutine in response to a request
 // from the network thread to apply a group signature to a message that is just
 // about to be sent to the destination server.