Add SALT for pass phrase handling

src/random.h

@@ -5,8 +5,8 @@ void random_fini (void);
 const uint8_t *random_bytes_get (void);
 void random_bytes_free (const uint8_t *p);
 
-/* 4-byte salt */
-uint32_t get_salt (void);
+/* 8-byte salt */
+void random_get_salt (uint8_t *p);
 
 /* iterator returning a byta at a time */
 int random_gen (void *arg, unsigned char *output, size_t output_len);