c.Rands.bodyNonces or h.Nonces were not nil for the entire writing of…

… a header/body as later there was append()

model/headers/headers.go

@@ -214,21 +214,24 @@ func (h *Header) MarshalBinary() (data []byte, err error) {
 	if err != nil {
 		return nil, err
 	}
-	for _, headerPacket := range h.HeaderPackets {
+	nonces := h.Nonces
+	for i, headerPacket := range h.HeaderPackets {
 		if h.Nonces != nil {
-			headerPacket.Nonce = h.Nonces[0]
-			h.Nonces = h.Nonces[1:]
+			headerPacket.Nonce = nonces[i]
 		}
 		marshalledHeaderPacket, err := headerPacket.MarshalBinary()
 		if err != nil {
 			return nil, err
 		}
-		h.Nonces = append(h.Nonces, headerPacket.Nonce)
+		if h.Nonces == nil {
+			nonces = append(nonces, headerPacket.Nonce)
+		}
 		err = binary.Write(&buffer, binary.LittleEndian, marshalledHeaderPacket)
 		if err != nil {
 			return nil, err
 		}
 	}
+	h.Nonces = nonces
 
 	return buffer.Bytes(), nil
 }

streaming/out.go

@@ -28,6 +28,7 @@ type WriterRands struct {
 	dataKey      [chacha20poly1305.KeySize]byte
 	headerNonces []*[chacha20poly1305.NonceSize]byte
 	bodyNonces   []*[chacha20poly1305.NonceSize]byte
+	replicate    bool
 }
 
 // NewCrypt4GHWriter method constructs streaming.Crypt4GHWriter instance from io.Writer and corresponding keys.
@@ -55,6 +56,7 @@ func NewCrypt4GHWriterWithRands(writer io.Writer,
 	rands *WriterRands,
 ) (*Crypt4GHWriter, error) {
 	crypt4GHWriter := Crypt4GHWriter{Rands: rands}
+	crypt4GHWriter.Rands.replicate = true
 
 	err := crypt4GHWriter.init(writer, writerPrivateKey, readerPublicKeyList, dataEditList)
 	if err != nil {
@@ -182,7 +184,7 @@ func (c *Crypt4GHWriter) flushBuffer() error {
 		DataEncryptionParametersHeaderPackets: []headers.DataEncryptionParametersHeaderPacket{c.dataEncryptionParametersHeaderPacket},
 		UnencryptedData:                       c.buffer.Bytes(),
 	}
-	if c.Rands.bodyNonces != nil {
+	if c.Rands.replicate {
 		segment.Nonce = c.Rands.bodyNonces[0]
 		c.Rands.bodyNonces = c.Rands.bodyNonces[1:]
 	}