diff --git a/services/src/main/java/org/keycloak/protocol/RestartLoginCookie.java b/services/src/main/java/org/keycloak/protocol/RestartLoginCookie.java
index e259738de6..b4e037b337 100644
--- a/services/src/main/java/org/keycloak/protocol/RestartLoginCookie.java
+++ b/services/src/main/java/org/keycloak/protocol/RestartLoginCookie.java
@@ -64,6 +64,10 @@ public class RestartLoginCookie {
     @JsonProperty("notes")
     protected Map<String, String> notes = new HashMap<>();
 
+    @Deprecated // Backwards compatibility
+    @JsonProperty("cs")
+    protected String cs;
+
     public Map<String, String> getNotes() {
         return notes;
     }
diff --git a/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/client/KeycloakTestingClient.java b/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/client/KeycloakTestingClient.java
index 533dfbb08f..7c61206b28 100755
--- a/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/client/KeycloakTestingClient.java
+++ b/testsuite/integration-arquillian/tests/base/src/main/java/org/keycloak/testsuite/client/KeycloakTestingClient.java
@@ -90,14 +90,14 @@ public class KeycloakTestingClient {
 
         public <T> T fetch(FetchOnServer function, Class<T> clazz) throws RunOnServerException {
             try {
-                String s = fetch(function);
+                String s = fetchString(function);
                 return JsonSerialization.readValue(s, clazz);
             } catch (Exception e) {
                 throw new RuntimeException(e);
             }
         }
 
-        public String fetch(FetchOnServer function) throws RunOnServerException {
+        public String fetchString(FetchOnServer function) throws RunOnServerException {
             String encoded = SerializationUtil.encode(function);
 
             String result = testing(realm != null ? realm : "master").runOnServer(encoded);
diff --git a/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/forms/RestartCookieTest.java b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/forms/RestartCookieTest.java
new file mode 100644
index 0000000000..6135c5617d
--- /dev/null
+++ b/testsuite/integration-arquillian/tests/base/src/test/java/org/keycloak/testsuite/forms/RestartCookieTest.java
@@ -0,0 +1,128 @@
+/*
+ * Copyright 2017 Red Hat, Inc. and/or its affiliates
+ * and other contributors as indicated by the @author tags.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.keycloak.testsuite.forms;
+
+import java.io.IOException;
+
+import javax.mail.MessagingException;
+
+import org.jboss.arquillian.container.test.api.Deployment;
+import org.jboss.arquillian.graphene.page.Page;
+import org.jboss.shrinkwrap.api.spec.WebArchive;
+import org.junit.Rule;
+import org.junit.Test;
+import org.keycloak.admin.client.resource.UserResource;
+import org.keycloak.events.Details;
+import org.keycloak.events.Errors;
+import org.keycloak.jose.jws.JWSBuilder;
+import org.keycloak.models.KeyManager;
+import org.keycloak.models.KeycloakSession;
+import org.keycloak.models.RealmModel;
+import org.keycloak.protocol.RestartLoginCookie;
+import org.keycloak.representations.idm.RealmRepresentation;
+import org.keycloak.testsuite.AbstractTestRealmKeycloakTest;
+import org.keycloak.testsuite.Assert;
+import org.keycloak.testsuite.AssertEvents;
+import org.keycloak.testsuite.pages.LoginPage;
+import org.keycloak.testsuite.runonserver.RunOnServerDeployment;
+import org.openqa.selenium.Cookie;
+
+/**
+ * @author <a href="mailto:mposolda@redhat.com">Marek Posolda</a>
+ */
+public class RestartCookieTest extends AbstractTestRealmKeycloakTest {
+
+
+    @Page
+    protected LoginPage loginPage;
+
+
+    @Rule
+    public AssertEvents events = new AssertEvents(this);
+
+
+    @Deployment
+    public static WebArchive deploy() {
+        return RunOnServerDeployment.create(UserResource.class)
+                .addPackages(true, "org.keycloak.testsuite");
+    }
+
+
+    // KC_RESTART cookie from Keycloak 3.1.0
+    private static final String OLD_RESTART_COOKIE_JSON = "{\n" +
+            "  \"cs\": \"874a1ea8-5579-4f21-add0-903dd8e3ec1b\",\n" +
+            "  \"cid\": \"test-app\",\n" +
+            "  \"pty\": \"openid-connect\",\n" +
+            "  \"ruri\": \"http://localhost:8081/auth/realms/master/app/auth\",\n" +
+            "  \"act\": \"AUTHENTICATE\",\n" +
+            "  \"notes\": {\n" +
+            "    \"auth_type\": \"code\",\n" +
+            "    \"scope\": \"openid\",\n" +
+            "    \"iss\": \"http://localhost:8081/auth/realms/master/app/auth\",\n" +
+            "    \"response_type\": \"code\",\n" +
+            "    \"redirect_uri\": \"http://localhost:8081/auth/realms/master/app/auth/\",\n" +
+            "    \"state\": \"6c983e5b-2dc1-411a-9ed1-0f51095949c5\",\n" +
+            "    \"code_challenge_method\": \"plain\",\n" +
+            "    \"nonce\": \"65639660-99b2-4cdf-bc9f-9978fdce5b03\",\n" +
+            "    \"response_mode\": \"fragment\"\n" +
+            "  }\n" +
+            "}";
+
+    @Override
+    public void configureTestRealm(RealmRepresentation testRealm) {
+    }
+
+
+    // KEYCLOAK-5440
+    @Test
+    public void invalidLoginAndBackButton() throws IOException, MessagingException {
+        String oldRestartCookie = testingClient.server().fetchString((KeycloakSession session) -> {
+            try {
+                String cookieVal = OLD_RESTART_COOKIE_JSON.replace("\n", "").replace(" ", "");
+                RealmModel realm = session.realms().getRealmByName("test");
+
+                KeyManager.ActiveHmacKey activeKey = session.keys().getActiveHmacKey(realm);
+
+                String encodedToken = new JWSBuilder()
+                        .kid(activeKey.getKid())
+                        .content(cookieVal.getBytes("UTF-8"))
+                        .hmac256(activeKey.getSecretKey());
+
+                return encodedToken;
+
+
+            } catch (IOException ioe) {
+                throw new RuntimeException(ioe);
+            }
+        });
+
+        oauth.openLoginForm();
+
+        driver.manage().deleteAllCookies();
+        driver.manage().addCookie(new Cookie(RestartLoginCookie.KC_RESTART, oldRestartCookie));
+
+        loginPage.login("foo", "bar");
+        loginPage.assertCurrent();
+        Assert.assertEquals("You took too long to login. Login process starting from beginning.", loginPage.getError());
+
+        events.expectLogin().user((String) null).session((String) null).error(Errors.EXPIRED_CODE).clearDetails()
+                .detail(Details.RESTART_AFTER_TIMEOUT, "true")
+                .client((String) null)
+                .assertEvent();
+    }
+}