diff --git a/signature_parameters.go b/signature_parameters.go
index 56084b6..a429243 100644
--- a/signature_parameters.go
+++ b/signature_parameters.go
@@ -128,7 +128,7 @@ func (p *signatureParameters) fromInnerList(list httpsfv.InnerList) error {
 
 			p.tag = value
 		default:
-			return fmt.Errorf("%w: %s is unknown", ErrMalformedSignatureParameter, name)
+			// ignoring unknown parameter
 		}
 	}
 
diff --git a/signature_parameters_test.go b/signature_parameters_test.go
index 40e6390..46c2a8f 100644
--- a/signature_parameters_test.go
+++ b/signature_parameters_test.go
@@ -399,7 +399,7 @@ func TestSignatureParametersFromInnerList(t *testing.T) {
 			},
 		},
 		{
-			uc: "failing parsing unknown parameter",
+			uc: "preserving unknown signature parameter",
 			list: httpsfv.InnerList{
 				Params: func() *httpsfv.Params {
 					params := httpsfv.NewParams()
@@ -408,12 +408,14 @@ func TestSignatureParametersFromInnerList(t *testing.T) {
 					return params
 				}(),
 			},
-			assert: func(t *testing.T, err error, _ *signatureParameters) {
+			assert: func(t *testing.T, err error, params *signatureParameters) {
 				t.Helper()
 
-				require.Error(t, err)
-				require.ErrorIs(t, err, ErrMalformedSignatureParameter)
-				require.ErrorContains(t, err, "foo is unknown")
+				require.NoError(t, err)
+
+				value, ok := params.Params.Get("foo")
+				require.True(t, ok)
+				assert.Equal(t, 1, value)
 			},
 		},
 		{