diff --git a/include/ttyio.h b/include/ttyio.h
index 8e8722d7c..f3d83b9dc 100644
--- a/include/ttyio.h
+++ b/include/ttyio.h
@@ -30,9 +30,9 @@ int tty_batchmode( int onoff );
  void tty_printf (const char *fmt, ... );
  void tty_fprintf (FILE *fp, const char *fmt, ... );
 #endif
-void tty_print_string( byte *p, size_t n );
-void tty_print_utf8_string( byte *p, size_t n );
-void tty_print_utf8_string2( byte *p, size_t n, size_t max_n );
+void tty_print_string( const byte *p, size_t n );
+void tty_print_utf8_string( const byte *p, size_t n );
+void tty_print_utf8_string2( const byte *p, size_t n, size_t max_n );
 char *tty_get( const char *prompt );
 char *tty_get_hidden( const char *prompt );
 void tty_kill_prompt(void);
diff --git a/util/ChangeLog b/util/ChangeLog
index 67cbb70c8..94e42cc3f 100644
--- a/util/ChangeLog
+++ b/util/ChangeLog
@@ -1,3 +1,8 @@
+2003-10-08  Werner Koch  <wk@gnupg.org>
+
+	* ttyio.c (tty_print_string, tty_print_utf8_string2)
+	(tty_print_utf8_string): Made string arg const.
+
 2003-09-28  Timo Schulz  <twoaday@freakmail.de>
 
 	* strgutil.c [WIN32] (asprintf): New.
diff --git a/util/ttyio.c b/util/ttyio.c
index e68c92b17..076ab7c67 100644
--- a/util/ttyio.c
+++ b/util/ttyio.c
@@ -268,7 +268,7 @@ tty_fprintf (FILE *fp, const char *fmt, ... )
  * Print a string, but filter all control characters out.
  */
 void
-tty_print_string( byte *p, size_t n )
+tty_print_string( const byte *p, size_t n )
 {
     if (no_terminal)
 	return;
@@ -306,7 +306,7 @@ tty_print_string( byte *p, size_t n )
 }
 
 void
-tty_print_utf8_string2( byte *p, size_t n, size_t max_n )
+tty_print_utf8_string2 (const byte *p, size_t n, size_t max_n )
 {
     size_t i;
     char *buf;
@@ -337,7 +337,7 @@ tty_print_utf8_string2( byte *p, size_t n, size_t max_n )
 }
 
 void
-tty_print_utf8_string( byte *p, size_t n )
+tty_print_utf8_string( const byte *p, size_t n )
 {
     tty_print_utf8_string2( p, n, 0 );
 }