Expose SSID for display to the user (coyim#42)

Author: olabini

auth_state_machine.go

@@ -177,6 +177,8 @@ func (s authStateAwaitingDHKey) receiveDHKeyMessage(c *Conversation, msg []byte)
 	c.keys.setOurCurrentDHKeys(c.ake.secretExponent, c.ake.ourPublicValue)
 	c.keys.ourCounter++
 
+	c.sentRevealSig = true
+
 	return authStateAwaitingSig{revealSigMsg: revealSigMsg}, revealSigMsg, nil
 }
 
@@ -221,6 +223,8 @@ func (s authStateAwaitingRevealSig) receiveRevealSigMessage(c *Conversation, msg
 	c.keys.setOurCurrentDHKeys(c.ake.secretExponent, c.ake.ourPublicValue)
 	c.keys.ourCounter++
 
+	c.sentRevealSig = false
+
 	return authStateNone{}, sigMsg, c.akeHasFinished()
 }
 

auth_state_machine_test.go

@@ -149,6 +149,7 @@ func Test_receiveDHKey_TransitionsFromAwaitingDHKeyToAwaitingSigAndSendsRevealSi
 	ourDHCommitAKE.dhCommitMessage()
 
 	c := bobContextAtAwaitingDHKey()
+	c.sentRevealSig = false
 
 	state, msg, err := authStateAwaitingDHKey{}.receiveDHKeyMessage(c, fixtureDHKeyMsg(otrV3{})[otrv3HeaderLen:])
 
@@ -157,6 +158,7 @@ func Test_receiveDHKey_TransitionsFromAwaitingDHKeyToAwaitingSigAndSendsRevealSi
 	assertEquals(t, ok, true)
 	assertEquals(t, dhMsgType(msg), msgTypeRevealSig)
 	assertEquals(t, dhMsgVersion(msg), uint16(3))
+	assertEquals(t, c.sentRevealSig, true)
 }
 
 func Test_receiveDHKey_AtAwaitingDHKeyStoresGyAndSigKey(t *testing.T) {
@@ -236,12 +238,14 @@ func Test_receiveRevealSig_TransitionsFromAwaitingRevealSigToNoneOnSuccess(t *te
 	revealSignMsg := fixtureRevealSigMsgBody(otrV2{})
 
 	c := aliceContextAtAwaitingRevealSig()
+	c.sentRevealSig = true
 
 	state, msg, err := authStateAwaitingRevealSig{}.receiveRevealSigMessage(c, revealSignMsg)
 
 	assertEquals(t, err, nil)
 	assertEquals(t, state, authStateNone{})
 	assertEquals(t, dhMsgType(msg), msgTypeSig)
+	assertEquals(t, c.sentRevealSig, false)
 }
 
 func Test_receiveRevealSig_AtAwaitingRevealSigStoresOursAndTheirDHKeysAndIncreaseCounter(t *testing.T) {

conversation.go

@@ -48,7 +48,8 @@ type Conversation struct {
 	securityEventHandler SecurityEventHandler
 	receivedKeyHandler   ReceivedKeyHandler
 
-	debug bool
+	debug         bool
+	sentRevealSig bool
 }
 
 func (c *Conversation) messageHeader(msgType byte) ([]byte, error) {

ssid.go

@@ -0,0 +1,17 @@
+package otr3
+
+import "fmt"
+
+// SecureSessionID returns the secure session ID as two formatted strings
+// The index returned points to the string that should be highlighted
+func (c *Conversation) SecureSessionID() (parts []string, highlightIndex int) {
+	l := fmt.Sprintf("%0x", c.ssid[0:4])
+	r := fmt.Sprintf("%0x", c.ssid[4:])
+
+	ix := 1
+	if c.sentRevealSig {
+		ix = 0
+	}
+
+	return []string{l, r}, ix
+}

ssid_test.go

@@ -0,0 +1,26 @@
+package otr3
+
+import "testing"
+
+func Test_SecureSessionID_returnsTheSessionIDAsTwoFormattedStrings(t *testing.T) {
+	c := newConversation(nil, fixtureRand())
+	c.ssid = [8]byte{0x01, 0x02, 0xF3, 0x04, 0x00, 0x06, 0x07, 0x08}
+
+	parts, _ := c.SecureSessionID()
+
+	assertDeepEquals(t, parts[0], "0102f304")
+	assertDeepEquals(t, parts[1], "00060708")
+}
+
+func Test_SecureSessionID_returnsTheIndexOfTheValueThatShouldBeHighlighted(t *testing.T) {
+	c := newConversation(nil, fixtureRand())
+	c.ssid = [8]byte{0x01, 0x02, 0xF3, 0x04, 0x00, 0x06, 0x07, 0x08}
+
+	c.sentRevealSig = true
+	_, f := c.SecureSessionID()
+	assertEquals(t, f, 0)
+
+	c.sentRevealSig = false
+	_, f = c.SecureSessionID()
+	assertEquals(t, f, 1)
+}