diff --git oak-core/src/main/java/org/apache/jackrabbit/oak/security/authorization/accesscontrol/Util.java oak-core/src/main/java/org/apache/jackrabbit/oak/security/authorization/accesscontrol/Util.java
index e596eac..2e959cf 100644
--- oak-core/src/main/java/org/apache/jackrabbit/oak/security/authorization/accesscontrol/Util.java
+++ oak-core/src/main/java/org/apache/jackrabbit/oak/security/authorization/accesscontrol/Util.java
@@ -17,6 +17,8 @@
 package org.apache.jackrabbit.oak.security.authorization.accesscontrol;
 
 import java.security.Principal;
+import java.security.SecureRandom;
+import java.util.Random;
 import java.util.Set;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -121,13 +123,13 @@ final class Util implements AccessControlConstants {
      */
     @Nonnull
     public static String generateAceName(@Nonnull Tree aclTree, boolean isAllow) {
-        int i = 0;
-        String hint = (isAllow) ? "allow" : "deny";
-        String aceName = hint;
-        while (aclTree.hasChild(aceName)) {
-            aceName = hint + i;
-            i++;
-        }
+        String aceName;
+        Random random = new Random();
+
+        do {
+            aceName = ((isAllow) ? "allow" : "deny") + random.nextInt();
+        } while (aclTree.hasChild(aceName));
+
         return aceName;
     }
 
diff --git oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/AuthorizationContextTest.java oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/AuthorizationContextTest.java
index bc88c73..d297dbd 100644
--- oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/AuthorizationContextTest.java
+++ oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/AuthorizationContextTest.java
@@ -115,9 +115,12 @@ public class AuthorizationContextTest extends AbstractSecurityTest {
         Context ctx = AuthorizationContext.getInstance();
 
         String policyPath = "/rep:policy";
-        assertTrue(ctx.definesLocation(TreeLocation.create(root, policyPath + "/allow")));
-        assertTrue(ctx.definesLocation(TreeLocation.create(root, policyPath + "/allow/" + AccessControlConstants.REP_PRINCIPAL_NAME)));
-        assertTrue(ctx.definesLocation(TreeLocation.create(root, policyPath + "/allow/" + AccessControlConstants.REP_PRIVILEGES)));
+
+        String acePath = policyPath + "/" + root.getTree(policyPath).getChildren().iterator().next().getName();
+
+        assertTrue(ctx.definesLocation(TreeLocation.create(root, acePath)));
+        assertTrue(ctx.definesLocation(TreeLocation.create(root, acePath + "/" + AccessControlConstants.REP_PRINCIPAL_NAME)));
+        assertTrue(ctx.definesLocation(TreeLocation.create(root, acePath + "/" + AccessControlConstants.REP_PRIVILEGES)));
 
         List<String> existingRegular = ImmutableList.of(
                 "/",
diff --git oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/accesscontrol/UtilTest.java oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/accesscontrol/UtilTest.java
new file mode 100644
index 0000000..aa98b83
--- /dev/null
+++ oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/accesscontrol/UtilTest.java
@@ -0,0 +1,56 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.jackrabbit.oak.security.authorization.accesscontrol;
+
+import org.apache.jackrabbit.oak.AbstractSecurityTest;
+import org.apache.jackrabbit.oak.api.Tree;
+import org.junit.Before;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class UtilTest extends AbstractSecurityTest {
+
+    private static final String DENY = "deny";
+    private static final String ALLOW = "allow";
+
+    private Tree tree;
+
+    @Override
+    @Before
+    public void before() throws Exception {
+        super.before();
+
+        tree = root.getTree("/");
+    }
+
+    @Test
+    public void testGenerateAllowAceName() {
+        String name = Util.generateAceName(tree, true);
+
+        assertTrue(name.startsWith(ALLOW));
+        assertNotEquals(ALLOW, name);
+    }
+
+    @Test
+    public void testGenerateDenyAceName() {
+        String name = Util.generateAceName(tree, false);
+
+        assertTrue(name.startsWith(DENY));
+        assertNotEquals(DENY, name);
+    }
+
+}
diff --git oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/restriction/RestrictionProviderImplTest.java oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/restriction/RestrictionProviderImplTest.java
index 8b989fc..9388b12 100644
--- oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/restriction/RestrictionProviderImplTest.java
+++ oak-core/src/test/java/org/apache/jackrabbit/oak/security/authorization/restriction/RestrictionProviderImplTest.java
@@ -190,7 +190,7 @@ public class RestrictionProviderImplTest extends AbstractAccessControlTest imple
             acMgr.setPolicy(path, acl);
 
             try {
-                provider.validateRestrictions(path, t.getChild(REP_POLICY).getChild("allow"));
+                provider.validateRestrictions(path, t.getChild(REP_POLICY).getChildren().iterator().next());
                 fail("AccessControlException expected.");
             } catch (AccessControlException e) {
                 // success