/*----- Functions provided ------------------------------------------------*/
+/* --- @des_fixparity@ --- *
+ *
+ * Arguments: @octet *z@ = output buffer pointer, or null
+ * @const octet *p@ = input buffer pointer
+ * @size_t sz@ = size of the buffers
+ *
+ * Returns: Zero if the input already had correct parity, @-1@ if changes
+ * were necessary (in constant time).
+ *
+ * Use: Check the @sz@ bytes at @p@ for odd parity (as used in DES
+ * keys); if @z@ is not null, then copy a parity-fixed version
+ * of @p@ to @z@. The two buffers at @p@ and @z@ may coincide,
+ * or be disjoint, but not otherwise overlap.
+ */
+
+extern int des_fixparity(octet */*z*/, const octet */*p*/, size_t /*sz*/);
+
/* --- @des_expand@ --- *
*
* Arguments: @const octet *k@ = pointer to key material