diff --git a/crypto/bn/bn_print.c b/crypto/bn/bn_print.c
index 2db550d47..782a96e7e 100644
--- a/crypto/bn/bn_print.c
+++ b/crypto/bn/bn_print.c
@@ -326,7 +326,7 @@ void bn_dump1(FILE *o, const char *a, BN_ULONG *b,int n)
 	int i;
 	fprintf(o, "%s=", a);
 	for (i=n-1;i>=0;i--)
-		fprintf(o, "%08lX", b[i]);
+		fprintf(o, "%08lX", b[i]); /* assumes 32-bit BN_ULONG */
 	fprintf(o, "\n");
 	}
 #endif