getDerSignature :: Get Signature
getDerSignature = do
  sequenceCode <- Get.getWord8
  derLength <- fromIntegral <$> Get.getWord8
  Get.getWord8
  xLength <- fromIntegral <$> Get.getWord8
  x <- roll BE <$> Get.getByteString xLength
  Get.getWord8
  yLength <- fromIntegral <$> Get.getWord8
  y <- roll BE <$> Get.getByteString yLength
  return $
    Signature x y
getDerSignature :: Get Signature
getDerSignature = do
  sequenceCode <- Get.getWord8
  derLength <- fromIntegral <$> Get.getWord8
  Get.getWord8
  xLength <- fromIntegral <$> Get.getWord8
  x <- roll BE <$> Get.getByteString xLength
  Get.getWord8
  yLength <- fromIntegral <$> Get.getWord8
  y <- roll BE <$> Get.getByteString yLength
  return $
    Signature x y
getDerSignature = do
  sequenceCode <- Get.getWord8
  derLength <- fromIntegral <$> Get.getWord8
  Get.getWord8
  xLength <- fromIntegral <$> Get.getWord8
  x <- roll BE <$> Get.getByteString xLength
  Get.getWord8
  yLength <- fromIntegral <$> Get.getWord8
  y <- roll BE <$> Get.getByteString yLength
  return $
    Signature x y