diff --git a/request.go b/request.go
index 48c6f8c..87a35d7 100644
--- a/request.go
+++ b/request.go
@@ -117,9 +117,9 @@ func NewRequest(opts RequestOptions) (*Request, error) {
 	if err != nil {
 		return nil, &MalformedRequestError{Msg: err.Error()}
 	}
-	parameter := opts.HashAlgorithmParameters
-	if reflect.DeepEqual(parameter, asn1.RawValue{}) {
-		parameter = asn1.NullRawValue
+	hashAlgParameter := opts.HashAlgorithmParameters
+	if reflect.DeepEqual(hashAlgParameter, asn1.RawValue{}) {
+		hashAlgParameter = asn1.NullRawValue
 	}
 	var nonce *big.Int
 	if !opts.NoNonce {
@@ -138,7 +138,7 @@ func NewRequest(opts RequestOptions) (*Request, error) {
 		MessageImprint: MessageImprint{
 			HashAlgorithm: pkix.AlgorithmIdentifier{
 				Algorithm:  hashAlg,
-				Parameters: parameter,
+				Parameters: hashAlgParameter,
 			},
 			HashedMessage: digest,
 		},
diff --git a/request_test.go b/request_test.go
index dac5e1f..2941d88 100644
--- a/request_test.go
+++ b/request_test.go
@@ -19,6 +19,7 @@ import (
 	"encoding/asn1"
 	"errors"
 	"fmt"
+	"reflect"
 	"testing"
 
 	"github.com/notaryproject/tspclient-go/internal/hashutil"
@@ -60,10 +61,13 @@ func TestNewRequest(t *testing.T) {
 		Content:       message,
 		HashAlgorithm: crypto.SHA256,
 	}
-	_, err = NewRequest(opts)
+	req, err := NewRequest(opts)
 	if err != nil {
 		t.Fatalf("expected nil error, but got %v", err)
 	}
+	if !reflect.DeepEqual(req.MessageImprint.HashAlgorithm.Parameters, asn1.NullRawValue) {
+		t.Fatalf("expected %v, but got %v", asn1.NullRawValue, req.MessageImprint.HashAlgorithm.Parameters)
+	}
 }
 
 func TestRequestMarshalBinary(t *testing.T) {