diff --git a/crypto_stream.go b/crypto_stream.go
index fbf7324ce..45d118daa 100644
--- a/crypto_stream.go
+++ b/crypto_stream.go
@@ -72,6 +72,8 @@ const (
 	TagORBT Tag = 'O' + 'R'<<8 + 'B'<<16 + 'T'<<24
 	// TagEXPY is the server config expiry
 	TagEXPY Tag = 'E' + 'X'<<8 + 'P'<<16 + 'Y'<<24
+	// TagCERT is the CERT data
+	TagCERT Tag = 0xff545243
 )
 
 var (
diff --git a/example/main.go b/example/main.go
index b866c7eb8..6724a0de7 100644
--- a/example/main.go
+++ b/example/main.go
@@ -16,6 +16,12 @@ const (
 )
 
 func main() {
+	path := "/Users/lucas/src/go/src/github.com/lucas-clemente/quic-go/example/"
+	keyData, err := crypto.LoadKeyData(path+"cert.der", path+"key.der")
+	if err != nil {
+		panic(err)
+	}
+
 	addr, err := net.ResolveUDPAddr("udp", "localhost:6121")
 	if err != nil {
 		panic(err)
@@ -73,26 +79,35 @@ func main() {
 	}
 
 	fmt.Printf("Tag: %d\n", messageTag)
-	fmt.Printf("Talking to: %s\n", string(cryptoData[quic.TagUAID]))
+	fmt.Printf("Talking to: %q\n", cryptoData[quic.TagUAID])
 
 	serverConfig := &bytes.Buffer{}
 	quic.WriteCryptoMessage(serverConfig, quic.TagSCFG, map[quic.Tag][]byte{
 		quic.TagSCID: []byte{0xC5, 0x1C, 0x73, 0x6B, 0x8F, 0x48, 0x49, 0xAE, 0xB3, 0x00, 0xA2, 0xD4, 0x4B, 0xA0, 0xCF, 0xDF},
 		quic.TagKEXS: []byte("C255"),
 		quic.TagAEAD: []byte("AESG"),
-		quic.TagPUBS: []byte{},
+		quic.TagPUBS: []byte{0x1, 0x2, 0x3},
 		quic.TagORBT: []byte{0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7},
 		quic.TagEXPY: []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
-		quic.TagVER:  []byte("Q030"),
+		quic.TagVER:  []byte("Q032"),
 	})
 
+	proof, err := keyData.SignServerProof(frame.Data, serverConfig.Bytes())
+	if err != nil {
+		panic(err)
+	}
 	serverReply := &bytes.Buffer{}
 	quic.WriteCryptoMessage(serverReply, quic.TagREJ, map[quic.Tag][]byte{
 		quic.TagSCFG: serverConfig.Bytes(),
+		quic.TagCERT: keyData.GetCERTdata(),
+		quic.TagPROF: proof,
 	})
 
 	replyFrame := &bytes.Buffer{}
 	replyFrame.WriteByte(0) // Private header
+	quic.WriteAckFrame(replyFrame, &quic.AckFrame{
+		LargestObserved: 1,
+	})
 	quic.WriteStreamFrame(replyFrame, &quic.StreamFrame{
 		StreamID: 1,
 		Data:     serverReply.Bytes(),
@@ -108,7 +123,7 @@ func main() {
 
 	conn.WriteToUDP(fullReply.Bytes(), remoteAddr)
 
-	n, remoteAddr, err = conn.ReadFromUDP(data)
+	n, _, err = conn.ReadFromUDP(data)
 	if err != nil {
 		panic(err)
 	}