diff --git a/opendkim/opendkim-db.c b/opendkim/opendkim-db.c
index 3e1a17b..ddf5969 100644
--- a/opendkim/opendkim-db.c
+++ b/opendkim/opendkim-db.c
@@ -2687,6 +2687,30 @@ dkimf_db_get(DKIMF_DB db, void *buf, size_t buflen,
 	assert(buf != NULL);
 	assert(req != NULL || reqnum == 0);
 
+	/*
+	**  Indicate "not found" if we require ASCII-only and there was
+	**  non-ASCII in the query.
+	*/
+
+	if ((db->db_flags & DKIMF_DB_FLAG_ASCIIONLY) != 0)
+	{
+		char *p;
+		char *end;
+
+		end = (char *) buf + buflen;
+
+		for (p = (char *) buf; p <= end; p++)
+		{
+			if (!isascii(*p))
+			{
+				if (*exists)
+					*exists = FALSE;
+
+				return 0;
+			}
+		}
+	}
+
 	switch (db->db_type)
 	{
 	  case DKIMF_DB_TYPE_FILE:
diff --git a/opendkim/opendkim-db.h b/opendkim/opendkim-db.h
index 93e7652..16513ef 100644
--- a/opendkim/opendkim-db.h
+++ b/opendkim/opendkim-db.h
@@ -25,6 +25,7 @@ static char opendkim_db_h_id[] = "@(#)$Id: opendkim-db.h,v 1.15 2010/09/16 04:47
 #define	DKIMF_DB_FLAG_VALLIST	0x08
 #define	DKIMF_DB_FLAG_USETLS	0x10
 #define	DKIMF_DB_FLAG_MAKELOCK	0x20
+#define	DKIMF_DB_FLAG_ASCIIONLY	0x40
 
 #define	DKIMF_DB_TYPE_UNKNOWN	(-1)
 #define	DKIMF_DB_TYPE_FILE	0
diff --git a/opendkim/opendkim.c b/opendkim/opendkim.c
index 2d89c9c..910a206 100644
--- a/opendkim/opendkim.c
+++ b/opendkim/opendkim.c
@@ -7178,6 +7178,7 @@ dkimf_config_load(struct config *data, struct dkimf_config *conf,
 			status = dkimf_db_open(&conf->conf_signtabledb,
 			                       conf->conf_signtable,
 			                       (DKIMF_DB_FLAG_ICASE |
+			                        DKIMF_DB_FLAG_ASCIIONLY |
 			                        DKIMF_DB_FLAG_READONLY),
 			                       NULL, &dberr);
 			if (status != 0)
@@ -15598,7 +15599,9 @@ main(int argc, char **argv)
 			*p = '\0';
 
 		p = NULL;
-		status = dkimf_db_open(&dbtest, dbname, DKIMF_DB_FLAG_READONLY,
+		status = dkimf_db_open(&dbtest, dbname,
+		                       (DKIMF_DB_FLAG_READONLY |
+		                        DKIMF_DB_FLAG_ASCIIONLY),
 		                       NULL, &p);
 		if (status != 0)
 		{