+/**
+ * Convert a block of binary data to HEX.
+ *
+ * @param data binary data to convert
+ * @param data_size number of bytes in @a data
+ * @return HEX string (lower case)
+ */
+char *
+GNUNET_DNSPARSER_bin_to_hex (const void *data,
+ size_t data_size);
+
+
+/**
+ * Convert a HEX string to block of binary data.
+ *
+ * @param hex HEX string to convert (may contain mixed case)
+ * @param data where to write result, must be
+ * at least `strlen(hex)/2` bytes long
+ * @return number of bytes written to data
+ */
+size_t
+GNUNET_DNSPARSER_hex_to_bin (const char *hex,
+ void *data);
+
+