diff --git a/certcrypto/crypto.go b/certcrypto/crypto.go
index 44f6e4d4..519c7a45 100644
--- a/certcrypto/crypto.go
+++ b/certcrypto/crypto.go
@@ -261,7 +261,7 @@ func generateDerCert(privateKey *rsa.PrivateKey, expiration time.Time, domain st
 	}
 
 	if expiration.IsZero() {
-		expiration = time.Now().Add(365)
+		expiration = time.Now().AddDate(1, 0, 0)
 	}
 
 	template := x509.Certificate{