diff --git a/Gopkg.lock b/Gopkg.lock
index d8810826..d7f7499f 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -62,7 +62,7 @@
   branch = "master"
   name = "github.com/jedisct1/dlog"
   packages = ["."]
-  revision = "fcbcc457e6a2b4eab2325a0902fd3d0a7d17e548"
+  revision = "b53fa44bbfb62dc284a052d828390b21f50d61f9"
 
 [[projects]]
   branch = "master"
diff --git a/dnscrypt-proxy/certs.go b/dnscrypt-proxy/certs.go
index 42d5213a..793b382a 100644
--- a/dnscrypt-proxy/certs.go
+++ b/dnscrypt-proxy/certs.go
@@ -71,6 +71,14 @@ func FetchCurrentCert(proxy *Proxy, proto string, pk ed25519.PublicKey, serverAd
 		serial := binary.BigEndian.Uint32(binCert[112:116])
 		tsBegin := binary.BigEndian.Uint32(binCert[116:120])
 		tsEnd := binary.BigEndian.Uint32(binCert[120:124])
+		if tsBegin >= tsEnd {
+			dlog.Warnf("[%v] certificate ends before it starts")
+			continue
+		}
+		ttl := tsEnd - tsBegin
+		if ttl > 86400 {
+			dlog.Warnf("[%v] the key validity period for this server is excessively long (%d days), significantly reducing reliability and forward security.", providerName, ttl/86400)
+		}
 		if now > tsEnd || now < tsBegin {
 			dlog.Debugf("[%v] Certificate not valid at the current date", providerName)
 			continue
@@ -108,7 +116,7 @@ func FetchCurrentCert(proxy *Proxy, proto string, pk ed25519.PublicKey, serverAd
 		certInfo.CryptoConstruction = cryptoConstruction
 		copy(certInfo.ServerPk[:], serverPk[:])
 		copy(certInfo.MagicQuery[:], binCert[104:112])
-		dlog.Noticef("[%v] Valid cert (crypto version %d) found - rtt: %dms", providerName, cryptoConstruction, rtt.Nanoseconds()/1000000)
+		dlog.Noticef("[%v] OK (crypto v%d) - rtt: %dms", providerName, cryptoConstruction, rtt.Nanoseconds()/1000000)
 	}
 	if certInfo.CryptoConstruction == UndefinedConstruction {
 		return certInfo, 0, errors.New("No useable certificate found")
diff --git a/vendor/github.com/jedisct1/dlog/dlog.go b/vendor/github.com/jedisct1/dlog/dlog.go
index 656ecf7d..744b8009 100644
--- a/vendor/github.com/jedisct1/dlog/dlog.go
+++ b/vendor/github.com/jedisct1/dlog/dlog.go
@@ -187,7 +187,7 @@ func logf(severity Severity, format string, args ...interface{}) {
 	if _globals.syslogger != nil {
 		(*_globals.syslogger).WriteLevel(severityToSyslogPriority[severity], []byte(message))
 	} else {
-		line := fmt.Sprintf("[%d-%02d-%02d %02d:%02d:%02d] [%s] [%s] %s\n", year, int(month), day, hour, minute, second, _globals.appName, SeverityName[severity], message)
+		line := fmt.Sprintf("[%d-%02d-%02d %02d:%02d:%02d] [%s] %s\n", year, int(month), day, hour, minute, second, SeverityName[severity], message)
 		if _globals.outFd != nil {
 			_globals.outFd.WriteString(line)
 			_globals.outFd.Sync()