diff --git a/cmd/wnode/main.go b/cmd/wnode/main.go
index 7f6173090a..9b634ecd43 100644
--- a/cmd/wnode/main.go
+++ b/cmd/wnode/main.go
@@ -493,6 +493,10 @@ func sendMsg(payload []byte) common.Hash {
 	}
 
 	msg := whisper.NewSentMessage(&params)
+	if msg == nil {
+		fmt.Printf("failed to create new message (OS level error)")
+		os.Exit(0)
+	}
 	envelope, err := msg.Wrap(&params)
 	if err != nil {
 		fmt.Printf("failed to seal message: %v \n", err)
@@ -622,6 +626,10 @@ func requestExpiredMessagesLoop() {
 		params.WorkTime = 5
 
 		msg := whisper.NewSentMessage(&params)
+		if msg == nil {
+			fmt.Printf("failed to create new message (OS level error)")
+			os.Exit(0)
+		}
 		env, err := msg.Wrap(&params)
 		if err != nil {
 			utils.Fatalf("Wrap failed: %s", err)
diff --git a/whisper/whisperv5/api.go b/whisper/whisperv5/api.go
index 6bc065b192..4d96507a8e 100644
--- a/whisper/whisperv5/api.go
+++ b/whisper/whisperv5/api.go
@@ -402,6 +402,11 @@ func (api *PublicWhisperAPI) Post(args PostArgs) error {
 
 	// encrypt and send
 	message := NewSentMessage(&params)
+	if message == nil {
+		info := "Post: failed create new message, probably due to failed rand function (OS level)"
+		log.Error(info)
+		return errors.New(info)
+	}
 	envelope, err := message.Wrap(&params)
 	if err != nil {
 		log.Error(err.Error())
diff --git a/whisper/whisperv5/filter_test.go b/whisper/whisperv5/filter_test.go
index 36cc887e3e..09a4961498 100644
--- a/whisper/whisperv5/filter_test.go
+++ b/whisper/whisperv5/filter_test.go
@@ -194,15 +194,9 @@ func TestMatchEnvelope(t *testing.T) {
 	}
 
 	// encrypt symmetrically
-<<<<<<< d4e2ecd2e1164b6a5106b20d135742a35656838f
 	i := mrand.Int() % 4
-	fsym.Topics[i] = params.Topic
-	fasym.Topics[i] = params.Topic
-=======
-	i := rand.Int() % 4
 	fsym.Topics[i] = params.Topic[:]
 	fasym.Topics[i] = params.Topic[:]
->>>>>>> whisper: variable topic size allowed for a filter
 	msg = NewSentMessage(params)
 	env, err = msg.Wrap(params)
 	if err != nil {
diff --git a/whisper/whisperv5/message.go b/whisper/whisperv5/message.go
index 6896681bcf..fa7d59d81e 100644
--- a/whisper/whisperv5/message.go
+++ b/whisper/whisperv5/message.go
@@ -102,14 +102,18 @@ func NewSentMessage(params *MessageParams) *SentMessage {
 	msg := SentMessage{}
 	msg.Raw = make([]byte, 1, len(params.Payload)+len(params.Payload)+signatureLength+padSizeLimitUpper)
 	msg.Raw[0] = 0 // set all the flags to zero
-	msg.appendPadding(params)
+	err := msg.appendPadding(params)
+	if err != nil {
+		log.Error(fmt.Sprintf("NewSentMessage: %s", err))
+		return nil
+	}
 	msg.Raw = append(msg.Raw, params.Payload...)
 	return &msg
 }
 
 // appendPadding appends the pseudorandom padding bytes and sets the padding flag.
 // The last byte contains the size of padding (thus, its size must not exceed 256).
-func (msg *SentMessage) appendPadding(params *MessageParams) {
+func (msg *SentMessage) appendPadding(params *MessageParams) error {
 	total := len(params.Payload) + 1
 	if params.Src != nil {
 		total += signatureLength
@@ -128,7 +132,10 @@ func (msg *SentMessage) appendPadding(params *MessageParams) {
 			panic("please fix the padding algorithm before releasing new version")
 		}
 		buf := make([]byte, padSize)
-		mrand.Read(buf[1:])
+		_, err := mrand.Read(buf[1:])
+		if err != nil {
+			return err
+		}
 		buf[0] = byte(padSize)
 		if params.Padding != nil {
 			copy(buf[1:], params.Padding)
@@ -136,6 +143,7 @@ func (msg *SentMessage) appendPadding(params *MessageParams) {
 		msg.Raw = append(msg.Raw, buf...)
 		msg.Raw[0] |= byte(0x1) // number of bytes indicating the padding size
 	}
+	return nil
 }
 
 // sign calculates and sets the cryptographic signature for the message,
diff --git a/whisper/whisperv5/whisper_test.go b/whisper/whisperv5/whisper_test.go
index fba843b554..ab072d7b43 100644
--- a/whisper/whisperv5/whisper_test.go
+++ b/whisper/whisperv5/whisper_test.go
@@ -391,7 +391,7 @@ func TestWhisperSymKeyManagement(t *testing.T) {
 	}
 
 	randomKey = make([]byte, aesKeyLength+1)
-	randomize(randomKey)
+	mrand.Read(randomKey)
 	id1, err = w.AddSymKeyDirect(randomKey)
 	if err == nil {
 		t.Fatalf("added the key with wrong size, seed %d.", seed)