decrypt :: Cipher -> ByteString -> IO ByteString
decrypt c cipher = BS.useAsCStringLen cipher $ \(ccipher, len) -> do
    c_decrypt c ccipher (fromIntegral len)
    BS.packCStringLen (ccipher, len)
decrypt :: Cipher -> ByteString -> IO ByteString
decrypt c cipher = BS.useAsCStringLen cipher $ \(ccipher, len) -> do
    c_decrypt c ccipher (fromIntegral len)
    BS.packCStringLen (ccipher, len)
decrypt c cipher = BS.useAsCStringLen cipher $ \(ccipher, len) -> do
    c_decrypt c ccipher (fromIntegral len)
    BS.packCStringLen (ccipher, len)