diff -up ntp-4.2.6p5/ntpd/ntp_config.c.defreqkey ntp-4.2.6p5/ntpd/ntp_config.c
--- ntp-4.2.6p5/ntpd/ntp_config.c.defreqkey	2017-04-13 15:29:13.287254279 +0200
+++ ntp-4.2.6p5/ntpd/ntp_config.c	2017-04-13 15:40:49.776307282 +0200
@@ -1870,8 +1870,8 @@ config_auth(
 			exit(1);
 		}
 
-		req_keytype = NID_md5;
-		req_hashlen = 16;
+		req_keytype = NID_sha1;
+		req_hashlen = 20;
 		MD5auth_setkey(req_keyid, req_keytype, rankey, sizeof(rankey));
 		authtrust(req_keyid, 1);
 	}