Show 3 last mnemonic representation of public key instead of public key during pairing

background.html

@@ -258,8 +258,8 @@
       <!-- Request Received -->
       <div class="requestReceivedView" style="display: none;">
         <h4>{{ requestReceivedTitle }}</h4>
-        Please verify that the pubkey shown here is your secondary device pubkey!
+        Please verify that the secret words shown below matches the ones on your other device!
-        <p class="secondaryPubKey"></p>
+        <p class="secretWords"></p>
         <div class='buttons'>
           <button class="skip">{{ skipText }}</button>
           <button id="allowPairing">{{ allowPairingText }}</button>
@@ -270,7 +270,7 @@
       <div class="requestAcceptedView" style="display: none;">
         <h4>{{ requestAcceptedTitle }}</h4>
         Sending pairing authorisation to:
-        <p class="secondaryPubKey"></p>
+        <p class="secretWords"></p>
         <p class="transmissionStatus">Please be patient...</p>
         <div class='buttons'>
           <button class="ok" style="display: none;">{{ okText }}</button>

js/views/device_pairing_dialog_view.js

@@ -12,6 +12,7 @@
     initialize() {
       this.pubKeyRequests = [];
       this.pubKey = null;
+      this.secretWords = null;
       this.accepted = false;
       this.view = '';
       this.render();
@@ -64,6 +65,10 @@
     nextPubKey() {
       // FIFO: pop at the back of the array using pop()
       this.pubKey = this.pubKeyRequests.pop();
+      this.secretWords = window.mnemonic.mn_encode(this.pubKey.slice(2), 'english')
+        .split(' ')
+        .slice(-3)
+        .join(' ');
     },
     showView() {
       const waitingForRequestView = this.$('.waitingForRequestView');
@@ -74,7 +79,7 @@
         waitingForRequestView.hide();
         requestAcceptedView.show();
       } else if (this.pubKey) {
-        this.$('.secondaryPubKey').text(this.pubKey);
+        this.$('.secretWords').text(this.secretWords);
         requestReceivedView.show();
         waitingForRequestView.hide();
         requestAcceptedView.hide();

js/views/standalone_registration_view.js

@@ -208,8 +208,13 @@
         countDownCallBack();
         this.pairingInterval = setInterval(countDownCallBack, 1000);
         const pubkey = textsecure.storage.user.getNumber();
+        const words = window.mnemonic.mn_encode(pubkey.slice(2), 'english')
+          .split(' ')
+          .slice(-3)
+          .join(' ');
+
         this.$('.standalone-secondary-device #pubkey').text(
-          `Here is your pubkey:\n${pubkey}`
+          `Here is your secret:\n${words}`
         );
       } catch (e) {
         onError(e);