diff --git a/authnresponse.go b/authnresponse.go
index 3064412..8b7cc79 100644
--- a/authnresponse.go
+++ b/authnresponse.go
@@ -59,7 +59,7 @@ func (r *Response) Validate(s *ServiceProviderSettings) error {
 		return errors.New("no Assertions")
 	}
 
-	if len(r.Signature.SignatureValue.Value) == 0 {
+	if len(r.Signature.SignatureValue.Value) == 0 && len(r.Assertion.Signature.SignatureValue.Value) == 0 {
 		return errors.New("no signature")
 	}
 
diff --git a/types.go b/types.go
index e691c02..bc4ec39 100644
--- a/types.go
+++ b/types.go
@@ -203,6 +203,7 @@ type Assertion struct {
 	SAML               string `xml:"saml,attr"`
 	IssueInstant       string `xml:"IssueInstant,attr"`
 	Issuer             Issuer `xml:"Issuer"`
+	Signature          Signature
 	Subject            Subject
 	Conditions         Conditions
 	AttributeStatement AttributeStatement