diff --git a/cmd/up.go b/cmd/up.go
index df8466ac820..bf48bde8a5a 100644
--- a/cmd/up.go
+++ b/cmd/up.go
@@ -30,7 +30,7 @@ var (
 			}
 
 			ctx := context.Background()
-			signalClient, err := sig.NewClient(config.SignalAddr, myKey, ctx)
+			signalClient, err := sig.NewClient(ctx, config.SignalAddr, myKey)
 			if err != nil {
 				log.Errorf("error while connecting to the Signal Exchange Service %s: %s", config.SignalAddr, err)
 				os.Exit(ExitSetupFailed)
@@ -41,7 +41,10 @@ var (
 			engine := connection.NewEngine(signalClient, config.StunTurnURLs, config.WgIface, config.WgAddr)
 
 			err = engine.Start(myKey, config.Peers)
-
+			if err != nil {
+				log.Errorf("error while starting the engine: %s", err)
+				os.Exit(ExitSetupFailed)
+			}
 			//signalClient.WaitConnected()
 
 			SetupCloseHandler()
diff --git a/signal/client.go b/signal/client.go
index 353806858d1..28773dcf8a3 100644
--- a/signal/client.go
+++ b/signal/client.go
@@ -21,7 +21,7 @@ import (
 
 // A set of tools to exchange connection details (Wireguard endpoints) with the remote peer.
 
-// Wraps the Signal Exchange Service gRpc client
+// Client Wraps the Signal Exchange Service gRpc client
 type Client struct {
 	key           wgtypes.Key
 	encryptionKey string
@@ -33,12 +33,13 @@ type Client struct {
 	connWg sync.WaitGroup //todo use a channel instead??
 }
 
-// Closes underlying connections to the Signal Exchange
+// Close Closes underlying connections to the Signal Exchange
 func (c *Client) Close() error {
 	return c.signalConn.Close()
 }
 
-func NewClient(addr string, key wgtypes.Key, ctx context.Context) (*Client, error) {
+// NewClient creates a new Signal client
+func NewClient(ctx context.Context, addr string, key wgtypes.Key) (*Client, error) {
 
 	conn, err := grpc.DialContext(
 		ctx,
@@ -63,7 +64,7 @@ func NewClient(addr string, key wgtypes.Key, ctx context.Context) (*Client, erro
 	}, nil
 }
 
-// Connects to the Signal Exchange message stream and starts receiving messages.
+// Receive Connects to the Signal Exchange message stream and starts receiving messages.
 // The messages will be handled by msgHandler function provided.
 // This function runs a goroutine underneath and reconnects to the Signal Exchange if errors occur (e.g. Exchange restart)
 // The key is the identifier of our Peer (could be Wireguard public key)
@@ -124,12 +125,12 @@ func (c *Client) connect(key string, msgHandler func(msg *proto.Message) error)
 	return c.receive(stream, msgHandler)
 }
 
-// Waits until the client is connected to the message stream
+// WaitConnected waits until the client is connected to the message stream
 func (c *Client) WaitConnected() {
 	c.connWg.Wait()
 }
 
-// Sends a message to the remote Peer through the Signal Exchange using established stream connection to the Signal Server
+// SendToStream sends a message to the remote Peer through the Signal Exchange using established stream connection to the Signal Server
 // The Client.Receive method must be called before sending messages to establish initial connection to the Signal Exchange
 // Client.connWg can be used to wait
 func (c *Client) SendToStream(msg *proto.EncryptedMessage) error {
@@ -154,6 +155,9 @@ func (c *Client) decryptMessage(msg *proto.EncryptedMessage) (*proto.Message, er
 		return nil, err
 	}
 	decryptedBody, err := Decrypt(msg.GetBody(), remoteKey, c.key)
+	if err != nil {
+		return nil, err
+	}
 	body := &proto.Body{}
 	err = pb.Unmarshal(decryptedBody, body)
 	if err != nil {
@@ -190,7 +194,7 @@ func (c *Client) encryptMessage(msg *proto.Message) (*proto.EncryptedMessage, er
 	}, nil
 }
 
-// Sends a message to the remote Peer through the Signal Exchange.
+// Send sends a message to the remote Peer through the Signal Exchange.
 func (c *Client) Send(msg *proto.Message) error {
 
 	encryptedMessage, err := c.encryptMessage(msg)
@@ -206,7 +210,7 @@ func (c *Client) Send(msg *proto.Message) error {
 	return nil
 }
 
-// Receives messages from other peers coming through the Signal Exchange
+// receive receives messages from other peers coming through the Signal Exchange
 func (c *Client) receive(stream proto.SignalExchange_ConnectStreamClient,
 	msgHandler func(msg *proto.Message) error) error {
 
@@ -240,6 +244,7 @@ func (c *Client) receive(stream proto.SignalExchange_ConnectStreamClient,
 	}
 }
 
+// UnMarshalCredential parses the credentials from the message and returns a Credential instance
 func UnMarshalCredential(msg *proto.Message) (*Credential, error) {
 
 	credential := strings.Split(msg.GetBody().GetPayload(), ":")
@@ -252,6 +257,7 @@ func UnMarshalCredential(msg *proto.Message) (*Credential, error) {
 	}, nil
 }
 
+// MarshalCredential marsharl a Credential instance and returns a Message object
 func MarshalCredential(myKey wgtypes.Key, remoteKey wgtypes.Key, credential *Credential, t proto.Body_Type) (*proto.Message, error) {
 	return &proto.Message{
 		Key:       myKey.PublicKey().String(),
@@ -263,6 +269,7 @@ func MarshalCredential(myKey wgtypes.Key, remoteKey wgtypes.Key, credential *Cre
 	}, nil
 }
 
+// Credential is an instance of a Client's Credential
 type Credential struct {
 	UFrag string
 	Pwd   string
diff --git a/signal/encryption.go b/signal/encryption.go
index 2e10d66de2a..2f4f1bccb30 100644
--- a/signal/encryption.go
+++ b/signal/encryption.go
@@ -13,7 +13,7 @@ import (
 // These tools use Golang crypto package (Curve25519, XSalsa20 and Poly1305 to encrypt and authenticate)
 // Wireguard keys are used for encryption
 
-// Encrypts a message using local Wireguard private key and remote peer's public key.
+// Encrypt encrypts a message using local Wireguard private key and remote peer's public key.
 func Encrypt(msg []byte, peersPublicKey wgtypes.Key, privateKey wgtypes.Key) ([]byte, error) {
 	nonce, err := genNonce()
 	if err != nil {
@@ -22,7 +22,7 @@ func Encrypt(msg []byte, peersPublicKey wgtypes.Key, privateKey wgtypes.Key) ([]
 	return box.Seal(nonce[:], msg, nonce, toByte32(peersPublicKey), toByte32(privateKey)), nil
 }
 
-// Decrypts a message that has been encrypted by the remote peer using Wireguard private key and remote peer's public key.
+// Decrypt decrypts a message that has been encrypted by the remote peer using Wireguard private key and remote peer's public key.
 func Decrypt(encryptedMsg []byte, peersPublicKey wgtypes.Key, privateKey wgtypes.Key) ([]byte, error) {
 	nonce, err := genNonce()
 	if err != nil {
diff --git a/signal/fingerprint.go b/signal/fingerprint.go
index 7e350d5b1df..1a88e19ec39 100644
--- a/signal/fingerprint.go
+++ b/signal/fingerprint.go
@@ -6,10 +6,11 @@ import (
 )
 
 const (
+	// HexTable Table of Hexadecimal chars
 	HexTable = "0123456789abcdef"
 )
 
-// Generates a SHA256 Fingerprint of the string
+// FingerPrint generates a SHA256 Fingerprint of the string
 func FingerPrint(key string) string {
 	hasher := sha256.New()
 	hasher.Write([]byte(key))
diff --git a/signal/peer/peer.go b/signal/peer/peer.go
index 5f08a5ebe59..355cdc0891d 100644
--- a/signal/peer/peer.go
+++ b/signal/peer/peer.go
@@ -5,7 +5,7 @@ import (
 	"github.com/wiretrustee/wiretrustee/signal/proto"
 )
 
-// Representation of a connected Peer
+// Peer representation of a connected Peer
 type Peer struct {
 	// a unique id of the Peer (e.g. sha256 fingerprint of the Wireguard public key)
 	Id string
@@ -14,6 +14,7 @@ type Peer struct {
 	Stream proto.SignalExchange_ConnectStreamServer
 }
 
+// NewPeer creates a new instance of a connected Peer
 func NewPeer(id string, stream proto.SignalExchange_ConnectStreamServer) *Peer {
 	return &Peer{
 		Id:     id,
@@ -21,19 +22,20 @@ func NewPeer(id string, stream proto.SignalExchange_ConnectStreamServer) *Peer {
 	}
 }
 
-// registry that holds all currently connected Peers
+// Registry registry that holds all currently connected Peers
 type Registry struct {
 	// Peer.key -> Peer
 	Peers map[string]*Peer
 }
 
+// NewRegistry creates a new connected Peer registry
 func NewRegistry() *Registry {
 	return &Registry{
 		Peers: make(map[string]*Peer),
 	}
 }
 
-// Registers peer in the registry
+// Register registers peer in the registry
 func (reg *Registry) Register(peer *Peer) {
 	if _, exists := reg.Peers[peer.Id]; exists {
 		log.Warnf("peer [%s] has been already registered", peer.Id)
@@ -45,7 +47,7 @@ func (reg *Registry) Register(peer *Peer) {
 	reg.Peers[peer.Id] = peer
 }
 
-// Deregister Peer from the Registry (usually once it disconnects)
+// DeregisterHub deregister Peer from the Registry (usually once it disconnects)
 func (reg *Registry) DeregisterHub(peer *Peer) {
 	if _, ok := reg.Peers[peer.Id]; ok {
 		delete(reg.Peers, peer.Id)
diff --git a/signal/signal.go b/signal/signal.go
index 91b5bd5f3a9..efd381f443d 100644
--- a/signal/signal.go
+++ b/signal/signal.go
@@ -2,7 +2,6 @@ package signal
 
 import (
 	"context"
-	"flag"
 	"fmt"
 	log "github.com/sirupsen/logrus"
 	"github.com/wiretrustee/wiretrustee/signal/peer"
@@ -13,20 +12,19 @@ import (
 	"io"
 )
 
-var (
-	port = flag.Int("port", 10000, "The server port")
-)
-
+// SignalExchangeServer an instance of a Signal server
 type SignalExchangeServer struct {
 	registry *peer.Registry
 }
 
+// NewServer creates a new Signal server
 func NewServer() *SignalExchangeServer {
 	return &SignalExchangeServer{
 		registry: peer.NewRegistry(),
 	}
 }
 
+// Send forwards a message to the signal peer
 func (s *SignalExchangeServer) Send(ctx context.Context, msg *proto.EncryptedMessage) (*proto.EncryptedMessage, error) {
 
 	if _, found := s.registry.Peers[msg.Key]; !found {
@@ -47,6 +45,7 @@ func (s *SignalExchangeServer) Send(ctx context.Context, msg *proto.EncryptedMes
 	return &proto.EncryptedMessage{}, nil
 }
 
+// ConnectStream connects to the exchange stream
 func (s *SignalExchangeServer) ConnectStream(stream proto.SignalExchange_ConnectStreamServer) error {
 	p, err := s.connectPeer(stream)
 	if err != nil {