diff --git a/signature/jws/envelope.go b/signature/jws/envelope.go
index 3dbb1e17..970f9b28 100644
--- a/signature/jws/envelope.go
+++ b/signature/jws/envelope.go
@@ -45,24 +45,14 @@ func ParseEnvelope(envelopeBytes []byte) (signature.Envelope, error) {
 
 // Sign signs the envelope and return the encoded message
 func (e *envelope) Sign(req *signature.SignRequest) ([]byte, error) {
-	// check signer type
-	var (
-		method signingMethod
-		err    error
-	)
-	if localSigner, ok := req.Signer.(signature.LocalSigner); ok {
-		// for local signer
-		method, err = newLocalSigningMethod(localSigner)
-	} else {
-		// for remote signer
-		method, err = newRemoteSigningMethod(req.Signer)
-	}
+	// get signingMethod for JWT package
+	method, err := getSigningMethod(req.Signer)
 	if err != nil {
 		return nil, &signature.MalformedSignRequestError{Msg: err.Error()}
 	}
 
 	// get all attributes ready to be signed
-	signedAttrs, err := getSignedAttrs(req, method.Alg())
+	signedAttrs, err := getSignedAttributes(req, method.Alg())
 	if err != nil {
 		return nil, err
 	}
diff --git a/signature/jws/jws.go b/signature/jws/jws.go
index 8afb9baf..03cd4d66 100644
--- a/signature/jws/jws.go
+++ b/signature/jws/jws.go
@@ -176,8 +176,8 @@ func generateJWS(compact string, req *signature.SignRequest, certs []*x509.Certi
 	}, nil
 }
 
-// getSignerAttrs merge extended signed attributes and protected header to be signed attributes
-func getSignedAttrs(req *signature.SignRequest, algorithm string) (map[string]interface{}, error) {
+// getSignerAttributes merge extended signed attributes and protected header to be signed attributes
+func getSignedAttributes(req *signature.SignRequest, algorithm string) (map[string]interface{}, error) {
 	extAttrs := make(map[string]interface{})
 	crit := []string{headerKeySigningScheme}
 
diff --git a/signature/jws/jwt.go b/signature/jws/jwt.go
index a0c9f3c2..f9463e85 100644
--- a/signature/jws/jwt.go
+++ b/signature/jws/jwt.go
@@ -107,6 +107,16 @@ func (s *localSigningMethod) PrivateKey() crypto.PrivateKey {
 	return s.signer.PrivateKey()
 }
 
+// getSigningMethod return signingMethod for the given signer
+func getSigningMethod(signer signature.Signer) (signingMethod, error) {
+	if localSigner, ok := signer.(signature.LocalSigner); ok {
+		// for local signer
+		return newLocalSigningMethod(localSigner)
+	}
+	// for remote signer
+	return newRemoteSigningMethod(signer)
+}
+
 // verifyJWT verifies the JWT token against the specified verification key
 func verifyJWT(tokenString string, publicKey interface{}) error {
 	parser := jwt.NewParser(