func (sc *SecretConnection) Read(data []byte) (n int, err error) {
	if 0 < len(sc.recvBuffer) {
		n_ := copy(data, sc.recvBuffer)
		sc.recvBuffer = sc.recvBuffer[n_:]
		return
	}

	sealedFrame := make([]byte, sealedFrameSize)
	_, err = io.ReadFull(sc.conn, sealedFrame)
	if err != nil {
		return
	}

	// decrypt the frame
	var frame = make([]byte, totalFrameSize)
	// fmt.Printf("secretbox.Open(sealed:%X,recvNonce:%X,shrSecret:%X\n", sealedFrame, sc.recvNonce, sc.shrSecret)
	_, ok := secretbox.Open(frame[:0], sealedFrame, sc.recvNonce, sc.shrSecret)
	if !ok {
		return n, errors.New("Failed to decrypt SecretConnection")
	}
	incr2Nonce(sc.recvNonce)
	// end decryption

	var chunkLength = binary.BigEndian.Uint16(frame) // read the first two bytes
	if chunkLength > dataMaxSize {
		return 0, errors.New("chunkLength is greater than dataMaxSize")
	}
	var chunk = frame[dataLenSize : dataLenSize+chunkLength]

	n = copy(data, chunk)
	sc.recvBuffer = chunk[n:]
	return
}
func (sc *SecretConnection) Read(data []byte) (n int, err error) {
	if 0 < len(sc.recvBuffer) {
		n_ := copy(data, sc.recvBuffer)
		sc.recvBuffer = sc.recvBuffer[n_:]
		return
	}

	sealedFrame := make([]byte, sealedFrameSize)
	_, err = io.ReadFull(sc.conn, sealedFrame)
	if err != nil {
		return
	}

	
	var frame = make([]byte, totalFrameSize)
	
	_, ok := secretbox.Open(frame[:0], sealedFrame, sc.recvNonce, sc.shrSecret)
	if !ok {
		return n, errors.New("Failed to decrypt SecretConnection")
	}
	incr2Nonce(sc.recvNonce)
	

	var chunkLength = binary.BigEndian.Uint16(frame) 
	if chunkLength > dataMaxSize {
		return 0, errors.New("chunkLength is greater than dataMaxSize")
	}
	var chunk = frame[dataLenSize : dataLenSize+chunkLength]

	n = copy(data, chunk)
	sc.recvBuffer = chunk[n:]
	return
}
func ( sc * SecretConnection ) Read ( data [ ] byte ) ( n int , err error ) { if 0 < len ( sc . recvBuffer ) { n_ := copy ( data , sc . recvBuffer ) sc . recvBuffer = sc . recvBuffer [ n_ : ] return } sealedFrame := make ( [ ] byte , sealedFrameSize ) _ , err = io . ReadFull ( sc . conn , sealedFrame ) if err != nil { return } // decrypt the frame var frame = make ( [ ] byte , totalFrameSize ) // fmt.Printf("secretbox.Open(sealed:%X,recvNonce:%X,shrSecret:%X\n", sealedFrame, sc.recvNonce, sc.shrSecret) _ , ok := secretbox . Open ( frame [ : 0 ] , sealedFrame , sc . recvNonce , sc . shrSecret ) if ! ok { return n , errors . New ( " " ) } incr2Nonce ( sc . recvNonce ) // end decryption var chunkLength = binary . BigEndian . Uint16 ( frame ) // read the first two bytes if chunkLength > dataMaxSize { return 0 , errors . New ( " " ) } var chunk = frame [ dataLenSize : dataLenSize + chunkLength ] n = copy ( data , chunk ) sc . recvBuffer = chunk [ n : ] return }
// CONTRACT: data smaller than dataMaxSize is read atomically.
CONTRACT : data smaller than dataMaxSize is read atomically .