--- pgp/src/usuals.h	2018/04/24 16:39:35	1.1.1.3
+++ pgp/src/usuals.h	2018/04/24 16:40:27	1.1.1.4
@@ -20,8 +20,8 @@ typedef unsigned long word32;	/* values
 #endif	/* if TRUE not already defined */
 
 #ifndef min	/* if min macro not already defined */
-#define min(a,b) ( (a)<(b) ? (a) : (b) )
-#define max(a,b) ( (a)>(b) ? (a) : (b) )
+#define min(a,b) (((a)<(b)) ? (a) : (b) )
+#define max(a,b) (((a)>(b)) ? (a) : (b) )
 #endif	/* if min macro not already defined */
 
 /* void for use in pointers */
@@ -31,5 +31,11 @@ typedef unsigned long word32;	/* values
 #define	VOID	char
 #endif
 
-#endif	/* if USUALS not already defined */
+	/* Zero-fill the byte buffer. */
+#define fill0(buffer,count)	memset( buffer, 0, count )
+
+	/* This macro is for burning sensitive data.  Many of the
+	   file I/O routines use it for zapping buffers */
+#define burn(x) fill0((VOID *)&(x),sizeof(x))
 
+#endif	/* if USUALS not already defined */