+/** @brief Encrypt using Arcfour stream cipher
+ * @param context Context structure
+ * @param inbuf Input buffer
+ * @param outbuf Output buffer
+ * @param length Number of bytes in @p inbuf
+ *
+ * Copies from @p inbuf to @p outbuf, encrypting (or decrypting) using
+ * the stream controlled by @p context.
+ */