diff --git a/include/libssh/bignum.h b/include/libssh/bignum.h
index df77ebeb..71970e3e 100644
--- a/include/libssh/bignum.h
+++ b/include/libssh/bignum.h
@@ -27,7 +27,7 @@
 bignum ssh_make_string_bn(ssh_string string);
 void ssh_make_string_bn_inplace(ssh_string string, bignum bnout);
 ssh_string ssh_make_bignum_string(bignum num);
-void ssh_print_bignum(const char *which,bignum num);
+void ssh_print_bignum(const char *which, const bignum num);
 
 
 #endif /* BIGNUM_H_ */
diff --git a/src/bignum.c b/src/bignum.c
index de21d6b3..fd6cf954 100644
--- a/src/bignum.c
+++ b/src/bignum.c
@@ -93,7 +93,7 @@ void ssh_make_string_bn_inplace(ssh_string string, bignum bnout) {
 }
 
 /* prints the bignum on stderr */
-void ssh_print_bignum(const char *which, bignum num) {
+void ssh_print_bignum(const char *which, const bignum num) {
 #ifdef HAVE_LIBGCRYPT
   unsigned char *hex = NULL;
   bignum_bn2hex(num, &hex);