diff --git a/client/peer.go b/client/peer.go
index c5a71ed..27ca4c9 100644
--- a/client/peer.go
+++ b/client/peer.go
@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"forge.redroom.link/yves/meowlib"
+	"google.golang.org/protobuf/proto"
 )
 
 type Peer struct {
@@ -53,6 +54,18 @@ func (pl *PeerList) GetFromName(name string) *Peer {
 	return nil
 }
 
+func (p *Peer) BuildSimpleUserUMessage(message []byte) ([]byte, error) {
+	var msg meowlib.UserMessage
+	msg.From = p.Me.Public
+	msg.Data = message
+	msg.Type = "1"
+	out, err := proto.Marshal(&msg)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 // AsymEncryptMessage prepares a message to send to a specific peer contact
 func (p *Peer) AsymEncryptMessage(Message []byte) (EncryptedMessage []byte, Signature []byte, Servers []*meowlib.Server, err error) {
 	EncryptedMessage, Signature, err = meowlib.AsymEncryptAndSign(p.Contact.EncryptionPublicKey, p.Me.Private, Message)
diff --git a/contactcard.go b/contactcard.go
index 4a89db3..04077ca 100644
--- a/contactcard.go
+++ b/contactcard.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/makiuchi-d/gozxing"
 	"github.com/makiuchi-d/gozxing/qrcode"
+	"google.golang.org/protobuf/proto"
 )
 
 func ServerFromUrl(url string) *Server {
@@ -26,10 +27,12 @@ func (Contact *ContactCard) AddUrls(urls []string) {
 	}
 }
 
-func (Contact *ContactCard) WritePng(filename string) {
-	jsonContact, _ := json.Marshal(Contact)
-	//imgdata := base64.StdEncoding.EncodeToString(jsonContact)
-	size := int(math.Sqrt(float64(len(jsonContact))/3)) + 1
+func (contact *ContactCard) WritePng(filename string) {
+	out, err := proto.Marshal(contact)
+	if err != nil {
+		println(err)
+	}
+	size := int(math.Sqrt(float64(len(out))/3)) + 1
 	println(size)
 
 	// Create a colored i	mage of the given width and height.
@@ -37,9 +40,9 @@ func (Contact *ContactCard) WritePng(filename string) {
 
 	for y := 0; y < size; y++ {
 		for x := 0; x < size*3; x = x + 3 {
-			p1 := uint8(jsonContact[x+y])
-			p2 := uint8(jsonContact[x+y+1])
-			p3 := uint8(jsonContact[x+y+2])
+			p1 := uint8(out[x+y])
+			p2 := uint8(out[x+y+1])
+			p3 := uint8(out[x+y+2])
 			img.Set(x/3, y, color.NRGBA{
 				R: p1,
 				G: p2,
diff --git a/endtoend_test.go b/endtoend_test.go
index f528931..e94b225 100644
--- a/endtoend_test.go
+++ b/endtoend_test.go
@@ -18,16 +18,16 @@ func TestEndToEnd(t *testing.T) {
 	Me, err := client.LoadIdentity("id.enc")
 	if err != nil {
 		fmt.Println("Failed : creating New identity...")
+		///////////////////////////
+		// Creating New Identity //
+		///////////////////////////
 		Me = client.CreateIdentity("myname")
-
-		//
 		// define my preferences (servers)
-		//
 		Me.MessageServers.Name = "Message Servers"
 		Me.MessageServers.AddUrls([]string{"http://127.0.0.1/meow/", "mqtt://127.0.0.1", "meow://127.0.0.1"})
-		//
-		// create an invitation for a friend, I want him/her to know me as Bender
-		//
+		////////////////////////////////////////////////////////////////////////////
+		// Create an invitation for a friend, I want him/her to know me as Bender //
+		////////////////////////////////////////////////////////////////////////////
 		fmt.Println("Creating an invitation for the first friend...")
 		MyFirstFriend, invitation := Me.InvitePeer("Bender", "myfirstfriend", []int{1, 2})
 		// print my invitation
@@ -35,8 +35,9 @@ func TestEndToEnd(t *testing.T) {
 		fmt.Println(string(a))
 		// TODO : Convert invitation to QR Code
 		invitation.WritePng("invitation.png")
-		//
-		// Simulate peer invitation response : generate the friend's keypair
+		///////////////////////////////////////
+		// Simulate peer invitation response //
+		///////////////////////////////////////
 		fmt.Println("Simulating first friend answer...")
 		var ReceivedContact meowlib.ContactCard
 
@@ -51,9 +52,10 @@ func TestEndToEnd(t *testing.T) {
 		FriendServer1KP := meowlib.NewKeyPair()
 		FriendServer1 := meowlib.Server{Name: "FriendServer1", Url: "http://myfriend.org/meow/", PublicKey: FriendServer1KP.Public, Description: "Fancy description", ConfidenceLevel: 1}
 		ReceivedContact.PullServers = append(ReceivedContact.PullServers, &FriendServer1)
-		// end Friend simulated invitation
 
-		// Finalize the contact with the invitation response
+		///////////////////////////////////////////////////////
+		// Finalize the contact with the invitation response //
+		///////////////////////////////////////////////////////
 		Me.FinalizeInvitation(MyFirstFriend, &ReceivedContact)
 		err = Me.Save("id.enc")
 		if err != nil {
@@ -63,35 +65,58 @@ func TestEndToEnd(t *testing.T) {
 		a, _ = json.Marshal(Me)
 		ioutil.WriteFile("id.json", a, 0644)
 		fmt.Println(string(a))
-
-		// create message to simulated friend
-		sentmessage := "Hello friend!"
-		EncMsg, EncMsgSignature, FriendServers, err := MyFirstFriend.AsymEncryptMessage([]byte(sentmessage))
+		/////////////////////////////////////
+		// Create a message to that friend //
+		/////////////////////////////////////
+		textmessage := "Hello friend!"
+		// Creating User message
+		usermessage, err := MyFirstFriend.BuildSimpleUserUMessage([]byte(textmessage))
+		if err != nil {
+			fmt.Println(err.Error())
+		}
+		// Encrypting it
+		EncMsg, EncMsgSignature, FriendServers, err := MyFirstFriend.AsymEncryptMessage(usermessage)
 		if err != nil {
 			fmt.Println(err.Error())
 		}
 		fmt.Println(len(FriendServers))
+		// Packing it
 		packedMsg := MyFirstFriend.Pack(EncMsg, EncMsgSignature)
 
 		srv := FriendServers[0]
 		intS1 := client.InternalServerFromServer(srv)
 
-		// Creating Server message
+		// Creating Server message for transporting the user message
 		toServerMessage, err := intS1.BuildMessageSendingMessage(&packedMsg)
+		if err != nil {
+			fmt.Println(err.Error())
+		}
 		// Encrypting it
 		encToServerMessage, encToServerMessageSignature, err := intS1.AsymEncryptMessage(toServerMessage)
+		if err != nil {
+			fmt.Println(err.Error())
+		}
 		// Packing it
 		protoPackedServerMsg, err := intS1.PackServerMessage(encToServerMessage, encToServerMessageSignature)
-		// Sending to server => fake action (network protocol trnasfer are not part of meowlib)
+		if err != nil {
+			fmt.Println(err.Error())
+		}
+		///////////////////////
+		// Sending to server //
+		///////////////////////
+		//=> fake action (network protocol transfer are not part of meowlib)
 		// You have to implement the netwok layer
+		// Just FYI printing final byte array size. Those bytes will be sent over the network.
 		println(len(protoPackedServerMsg))
 
-		//
-		// Simulating server side processing
-		//
+		///////////////////////////////////////
+		// Simulating server side processing //
+		///////////////////////////////////////
+
+		//////////////////////////////////////////////
+		// Back to client, decoding server response //
+		//////////////////////////////////////////////
 
-		//
-		// Back to client, decoding server response
 		//
 		decMess, err2 := MyFirstFriend.AsymDecryptMessage([]byte(EncMsg), EncMsgSignature)
 		if err2 != nil {