diff --git a/gatekeeperd/Android.mk b/gatekeeperd/Android.mk
index be3d6fc..ce050ae 100644
--- a/gatekeeperd/Android.mk
+++ b/gatekeeperd/Android.mk
@@ -25,9 +25,12 @@
 	libgatekeeper \
 	liblog \
 	libhardware \
+	libbase \
 	libutils \
 	libcrypto \
 	libkeystore_binder
 LOCAL_STATIC_LIBRARIES := libscrypt_static
 LOCAL_C_INCLUDES := external/scrypt/lib/crypto
 include $(BUILD_EXECUTABLE)
+
+include $(call first-makefiles-under,$(LOCAL_PATH))
diff --git a/gatekeeperd/IGateKeeperService.cpp b/gatekeeperd/IGateKeeperService.cpp
index f5bbbf1..95fbfd1 100644
--- a/gatekeeperd/IGateKeeperService.cpp
+++ b/gatekeeperd/IGateKeeperService.cpp
@@ -50,18 +50,25 @@
 
             uint8_t *out = NULL;
             uint32_t outSize = 0;
-            status_t ret = enroll(uid, currentPasswordHandle, currentPasswordHandleSize,
+            int ret = enroll(uid, currentPasswordHandle, currentPasswordHandleSize,
                     currentPassword, currentPasswordSize, desiredPassword,
                     desiredPasswordSize, &out, &outSize);
 
             reply->writeNoException();
-            if (ret == NO_ERROR && outSize > 0 && out != NULL) {
+            reply->writeInt32(1);
+            if (ret == 0 && outSize > 0 && out != NULL) {
+                reply->writeInt32(GATEKEEPER_RESPONSE_OK);
+                reply->writeInt32(0);
+                reply->writeInt32(outSize);
                 reply->writeInt32(outSize);
                 void *buf = reply->writeInplace(outSize);
                 memcpy(buf, out, outSize);
-                free(out);
+                delete[] out;
+            } else if (ret > 0) {
+                reply->writeInt32(GATEKEEPER_RESPONSE_RETRY);
+                reply->writeInt32(ret);
             } else {
-                reply->writeInt32(-1);
+                reply->writeInt32(GATEKEEPER_RESPONSE_ERROR);
             }
             return NO_ERROR;
         }
@@ -78,10 +85,23 @@
                 static_cast<const uint8_t *>(data.readInplace(currentPasswordSize));
             if (!currentPassword) currentPasswordSize = 0;
 
-            status_t ret = verify(uid, (uint8_t *) currentPasswordHandle,
-                    currentPasswordHandleSize, (uint8_t *) currentPassword, currentPasswordSize);
+            bool request_reenroll = false;
+            int ret = verify(uid, (uint8_t *) currentPasswordHandle,
+                    currentPasswordHandleSize, (uint8_t *) currentPassword, currentPasswordSize,
+                    &request_reenroll);
+
             reply->writeNoException();
-            reply->writeInt32(ret == NO_ERROR ? 1 : 0);
+            reply->writeInt32(1);
+            if (ret == 0) {
+                reply->writeInt32(GATEKEEPER_RESPONSE_OK);
+                reply->writeInt32(request_reenroll ? 1 : 0);
+                reply->writeInt32(0); // no payload returned from this call
+            } else if (ret > 0) {
+                reply->writeInt32(GATEKEEPER_RESPONSE_RETRY);
+                reply->writeInt32(ret);
+            } else {
+                reply->writeInt32(GATEKEEPER_RESPONSE_ERROR);
+            }
             return NO_ERROR;
         }
         case VERIFY_CHALLENGE: {
@@ -101,17 +121,25 @@
 
             uint8_t *out = NULL;
             uint32_t outSize = 0;
-            status_t ret = verifyChallenge(uid, challenge, (uint8_t *) currentPasswordHandle,
+            bool request_reenroll = false;
+            int ret = verifyChallenge(uid, challenge, (uint8_t *) currentPasswordHandle,
                     currentPasswordHandleSize, (uint8_t *) currentPassword, currentPasswordSize,
-                    &out, &outSize);
+                    &out, &outSize, &request_reenroll);
             reply->writeNoException();
-            if (ret == NO_ERROR && outSize > 0 && out != NULL) {
+            reply->writeInt32(1);
+            if (ret == 0 && outSize > 0 && out != NULL) {
+                reply->writeInt32(GATEKEEPER_RESPONSE_OK);
+                reply->writeInt32(request_reenroll ? 1 : 0);
+                reply->writeInt32(outSize);
                 reply->writeInt32(outSize);
                 void *buf = reply->writeInplace(outSize);
                 memcpy(buf, out, outSize);
-                free(out);
+                delete[] out;
+            } else if (ret > 0) {
+                reply->writeInt32(GATEKEEPER_RESPONSE_RETRY);
+                reply->writeInt32(ret);
             } else {
-                reply->writeInt32(-1);
+                reply->writeInt32(GATEKEEPER_RESPONSE_ERROR);
             }
             return NO_ERROR;
         }
diff --git a/gatekeeperd/IGateKeeperService.h b/gatekeeperd/IGateKeeperService.h
index a777318..f070486 100644
--- a/gatekeeperd/IGateKeeperService.h
+++ b/gatekeeperd/IGateKeeperService.h
@@ -35,6 +35,12 @@
         CLEAR_SECURE_USER_ID = IBinder::FIRST_CALL_TRANSACTION + 4,
     };
 
+    enum {
+        GATEKEEPER_RESPONSE_OK = 0,
+        GATEKEEPER_RESPONSE_RETRY = 1,
+        GATEKEEPER_RESPONSE_ERROR = -1,
+    };
+
     // DECLARE_META_INTERFACE - C++ client interface not needed
     static const android::String16 descriptor;
     virtual const android::String16& getInterfaceDescriptor() const;
@@ -43,8 +49,13 @@
 
     /**
      * Enrolls a password with the GateKeeper. Returns 0 on success, negative on failure.
+     * Returns:
+     * - 0 on success
+     * - A timestamp T > 0 if the call has failed due to throttling and should not
+     *   be reattempted until T milliseconds have elapsed
+     * - -1 on failure
      */
-    virtual status_t enroll(uint32_t uid,
+    virtual int enroll(uint32_t uid,
             const uint8_t *current_password_handle, uint32_t current_password_handle_length,
             const uint8_t *current_password, uint32_t current_password_length,
             const uint8_t *desired_password, uint32_t desired_password_length,
@@ -52,21 +63,29 @@
 
     /**
      * Verifies a password previously enrolled with the GateKeeper.
-     * Returns 0 on success, negative on failure.
+     * Returns:
+     * - 0 on success
+     * - A timestamp T > 0 if the call has failed due to throttling and should not
+     *   be reattempted until T milliseconds have elapsed
+     * - -1 on failure
      */
-    virtual status_t verify(uint32_t uid, const uint8_t *enrolled_password_handle,
+    virtual int verify(uint32_t uid, const uint8_t *enrolled_password_handle,
             uint32_t enrolled_password_handle_length,
-            const uint8_t *provided_password, uint32_t provided_password_length) = 0;
+            const uint8_t *provided_password, uint32_t provided_password_length,
+            bool *request_reenroll) = 0;
 
     /**
      * Verifies a password previously enrolled with the GateKeeper.
-     * Returns 0 on success, negative on failure.
+     * Returns:
+     * - 0 on success
+     * - A timestamp T > 0 if the call has failed due to throttling and should not
+     *   be reattempted until T milliseconds have elapsed
+     * - -1 on failure
      */
-    virtual status_t verifyChallenge(uint32_t uid, uint64_t challenge,
+    virtual int verifyChallenge(uint32_t uid, uint64_t challenge,
             const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
             const uint8_t *provided_password, uint32_t provided_password_length,
-            uint8_t **auth_token, uint32_t *auth_token_length) = 0;
-
+            uint8_t **auth_token, uint32_t *auth_token_length, bool *request_reenroll) = 0;
     /**
      * Returns the secure user ID for the provided android user
      */
diff --git a/gatekeeperd/SoftGateKeeper.h b/gatekeeperd/SoftGateKeeper.h
new file mode 100644
index 0000000..1ae45e6
--- /dev/null
+++ b/gatekeeperd/SoftGateKeeper.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright 2015 The Android Open Source Project
+ *
+ * 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.
+ *
+ */
+
+#ifndef SOFT_GATEKEEPER_H_
+#define SOFT_GATEKEEPER_H_
+
+extern "C" {
+#include <openssl/rand.h>
+#include <crypto_scrypt.h>
+}
+
+#include <UniquePtr.h>
+#include <gatekeeper/gatekeeper.h>
+#include <iostream>
+#include <unordered_map>
+
+namespace gatekeeper {
+
+
+class SoftGateKeeper : public GateKeeper {
+public:
+    static const uint32_t SIGNATURE_LENGTH_BYTES = 32;
+
+    // scrypt params
+    static const uint64_t N = 16384;
+    static const uint32_t r = 8;
+    static const uint32_t p = 1;
+
+    static const int MAX_UINT_32_CHARS = 11;
+
+    SoftGateKeeper() {
+        key_.reset(new uint8_t[SIGNATURE_LENGTH_BYTES]);
+        memset(key_.get(), 0, SIGNATURE_LENGTH_BYTES);
+    }
+
+    virtual ~SoftGateKeeper() {
+    }
+
+    virtual bool GetAuthTokenKey(const uint8_t **auth_token_key,
+            uint32_t *length) const {
+        if (auth_token_key == NULL || length == NULL) return false;
+        *auth_token_key = const_cast<const uint8_t *>(key_.get());
+        *length = SIGNATURE_LENGTH_BYTES;
+        return true;
+    }
+
+    virtual void GetPasswordKey(const uint8_t **password_key, uint32_t *length) {
+        if (password_key == NULL || length == NULL) return;
+        *password_key = const_cast<const uint8_t *>(key_.get());
+        *length = SIGNATURE_LENGTH_BYTES;
+    }
+
+    virtual void ComputePasswordSignature(uint8_t *signature, uint32_t signature_length,
+            const uint8_t *, uint32_t, const uint8_t *password,
+            uint32_t password_length, salt_t salt) const {
+        if (signature == NULL) return;
+        crypto_scrypt(password, password_length, reinterpret_cast<uint8_t *>(&salt),
+                sizeof(salt), N, r, p, signature, signature_length);
+    }
+
+    virtual void GetRandom(void *random, uint32_t requested_length) const {
+        if (random == NULL) return;
+        RAND_pseudo_bytes((uint8_t *) random, requested_length);
+    }
+
+    virtual void ComputeSignature(uint8_t *signature, uint32_t signature_length,
+            const uint8_t *, uint32_t, const uint8_t *, const uint32_t) const {
+        if (signature == NULL) return;
+        memset(signature, 0, signature_length);
+    }
+
+    virtual uint64_t GetMillisecondsSinceBoot() const {
+        struct timespec time;
+        int res = clock_gettime(CLOCK_BOOTTIME, &time);
+        if (res < 0) return 0;
+        return (time.tv_sec * 1000) + (time.tv_nsec / 1000 / 1000);
+    }
+
+    virtual bool IsHardwareBacked() const {
+        return false;
+    }
+
+    virtual bool GetFailureRecord(uint32_t uid, secure_id_t user_id, failure_record_t *record) {
+        failure_record_t *stored = &failure_map_[uid];
+        if (user_id != stored->secure_user_id) {
+            stored->secure_user_id = user_id;
+            stored->last_checked_timestamp = 0;
+            stored->failure_counter = 0;
+        }
+        memcpy(record, stored, sizeof(*record));
+        return true;
+    }
+
+    virtual void ClearFailureRecord(uint32_t uid, secure_id_t user_id) {
+        failure_record_t *stored = &failure_map_[uid];
+        stored->secure_user_id = user_id;
+        stored->last_checked_timestamp = 0;
+        stored->failure_counter = 0;
+    }
+
+    virtual bool WriteFailureRecord(uint32_t uid, failure_record_t *record) {
+        failure_map_[uid] = *record;
+        return true;
+    }
+
+private:
+    UniquePtr<uint8_t> key_;
+    std::unordered_map<uint32_t, failure_record_t> failure_map_;
+};
+}
+
+#endif // SOFT_GATEKEEPER_H_
+
diff --git a/gatekeeperd/SoftGateKeeperDevice.cpp b/gatekeeperd/SoftGateKeeperDevice.cpp
index b96bf8d..f5e2ce6 100644
--- a/gatekeeperd/SoftGateKeeperDevice.cpp
+++ b/gatekeeperd/SoftGateKeeperDevice.cpp
@@ -13,8 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-#include <gatekeeper/soft_gatekeeper.h>
-
+#include "SoftGateKeeper.h"
 #include "SoftGateKeeperDevice.h"
 
 namespace android {
@@ -58,8 +57,11 @@
 
     impl_->Enroll(request, &response);
 
-    if (response.error != ERROR_NONE)
+    if (response.error == ERROR_RETRY) {
+        return response.retry_timeout;
+    } else if (response.error != ERROR_NONE) {
         return -EINVAL;
+    }
 
     *enrolled_password_handle = response.enrolled_password_handle.buffer.release();
     *enrolled_password_handle_length = response.enrolled_password_handle.length;
@@ -69,7 +71,8 @@
 int SoftGateKeeperDevice::verify(uint32_t uid,
         uint64_t challenge, const uint8_t *enrolled_password_handle,
         uint32_t enrolled_password_handle_length, const uint8_t *provided_password,
-        uint32_t provided_password_length, uint8_t **auth_token, uint32_t *auth_token_length) {
+        uint32_t provided_password_length, uint8_t **auth_token, uint32_t *auth_token_length,
+        bool *request_reenroll) {
 
     if (enrolled_password_handle == NULL ||
             provided_password == NULL) {
@@ -87,14 +90,21 @@
 
     impl_->Verify(request, &response);
 
-    if (response.error != ERROR_NONE)
-       return -EINVAL;
+    if (response.error == ERROR_RETRY) {
+        return response.retry_timeout;
+    } else if (response.error != ERROR_NONE) {
+        return -EINVAL;
+    }
 
     if (auth_token != NULL && auth_token_length != NULL) {
        *auth_token = response.auth_token.buffer.release();
        *auth_token_length = response.auth_token.length;
     }
 
+    if (request_reenroll != NULL) {
+        *request_reenroll = response.request_reenroll;
+    }
+
     return 0;
 }
 } // namespace android
diff --git a/gatekeeperd/SoftGateKeeperDevice.h b/gatekeeperd/SoftGateKeeperDevice.h
index c0b5047..51a8511 100644
--- a/gatekeeperd/SoftGateKeeperDevice.h
+++ b/gatekeeperd/SoftGateKeeperDevice.h
@@ -17,7 +17,8 @@
 #ifndef SOFT_GATEKEEPER_DEVICE_H_
 #define SOFT_GATEKEEPER_DEVICE_H_
 
-#include <gatekeeper/soft_gatekeeper.h>
+#include "SoftGateKeeper.h"
+
 #include <UniquePtr.h>
 
 using namespace gatekeeper;
@@ -65,7 +66,7 @@
     int verify(uint32_t uid, uint64_t challenge,
             const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
             const uint8_t *provided_password, uint32_t provided_password_length,
-            uint8_t **auth_token, uint32_t *auth_token_length);
+            uint8_t **auth_token, uint32_t *auth_token_length, bool *request_reenroll);
 private:
     UniquePtr<GateKeeper> impl_;
 };
diff --git a/gatekeeperd/gatekeeperd.cpp b/gatekeeperd/gatekeeperd.cpp
index 72c7ba2..ad16fa5 100644
--- a/gatekeeperd/gatekeeperd.cpp
+++ b/gatekeeperd/gatekeeperd.cpp
@@ -102,7 +102,7 @@
         }
     }
 
-    virtual status_t enroll(uint32_t uid,
+    virtual int enroll(uint32_t uid,
             const uint8_t *current_password_handle, uint32_t current_password_handle_length,
             const uint8_t *current_password, uint32_t current_password_length,
             const uint8_t *desired_password, uint32_t desired_password_length,
@@ -132,29 +132,29 @@
                     enrolled_password_handle, enrolled_password_handle_length);
         }
 
-        if (ret >= 0) {
+        if (ret == 0) {
             gatekeeper::password_handle_t *handle =
                     reinterpret_cast<gatekeeper::password_handle_t *>(*enrolled_password_handle);
             store_sid(uid, handle->user_id);
-            return NO_ERROR;
         }
-        return UNKNOWN_ERROR;
+
+        return ret;
     }
 
-    virtual status_t verify(uint32_t uid,
+    virtual int verify(uint32_t uid,
             const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
-            const uint8_t *provided_password, uint32_t provided_password_length) {
+            const uint8_t *provided_password, uint32_t provided_password_length, bool *request_reenroll) {
         uint8_t *auth_token;
         uint32_t auth_token_length;
         return verifyChallenge(uid, 0, enrolled_password_handle, enrolled_password_handle_length,
                 provided_password, provided_password_length,
-                &auth_token, &auth_token_length);
+                &auth_token, &auth_token_length, request_reenroll);
     }
 
-    virtual status_t verifyChallenge(uint32_t uid, uint64_t challenge,
+    virtual int verifyChallenge(uint32_t uid, uint64_t challenge,
             const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
             const uint8_t *provided_password, uint32_t provided_password_length,
-            uint8_t **auth_token, uint32_t *auth_token_length) {
+            uint8_t **auth_token, uint32_t *auth_token_length, bool *request_reenroll) {
         IPCThreadState* ipc = IPCThreadState::self();
         const int calling_pid = ipc->getCallingPid();
         const int calling_uid = ipc->getCallingUid();
@@ -170,14 +170,16 @@
         if (device) {
             ret = device->verify(device, uid, challenge,
                 enrolled_password_handle, enrolled_password_handle_length,
-                provided_password, provided_password_length, auth_token, auth_token_length);
+                provided_password, provided_password_length, auth_token, auth_token_length,
+                request_reenroll);
         } else {
             ret = soft_device->verify(uid, challenge,
                 enrolled_password_handle, enrolled_password_handle_length,
-                provided_password, provided_password_length, auth_token, auth_token_length);
+                provided_password, provided_password_length, auth_token, auth_token_length,
+                request_reenroll);
         }
 
-        if (ret >= 0 && *auth_token != NULL && *auth_token_length > 0) {
+        if (ret == 0 && *auth_token != NULL && *auth_token_length > 0) {
             // TODO: cache service?
             sp<IServiceManager> sm = defaultServiceManager();
             sp<IBinder> binder = sm->getService(String16("android.security.keystore"));
@@ -192,13 +194,12 @@
             }
         }
 
-        if (ret >= 0) {
+        if (ret == 0) {
             maybe_store_sid(uid, reinterpret_cast<const gatekeeper::password_handle_t *>(
                         enrolled_password_handle)->user_id);
-            return NO_ERROR;
         }
 
-        return UNKNOWN_ERROR;
+        return ret;
     }
 
     virtual uint64_t getSecureUserId(uint32_t uid) {
diff --git a/gatekeeperd/tests/Android.mk b/gatekeeperd/tests/Android.mk
new file mode 100644
index 0000000..6fc4ac0
--- /dev/null
+++ b/gatekeeperd/tests/Android.mk
@@ -0,0 +1,29 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# 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.
+#
+
+LOCAL_PATH:= $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := gatekeeperd-unit-tests
+LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
+LOCAL_CFLAGS += -g -Wall -Werror -std=gnu++11 -Wno-missing-field-initializers
+LOCAL_SHARED_LIBRARIES := libgatekeeper libcrypto
+LOCAL_STATIC_LIBRARIES := libscrypt_static
+LOCAL_C_INCLUDES := external/scrypt/lib/crypto
+LOCAL_SRC_FILES := \
+	gatekeeper_test.cpp
+include $(BUILD_NATIVE_TEST)
+
diff --git a/gatekeeperd/tests/gatekeeper_test.cpp b/gatekeeperd/tests/gatekeeper_test.cpp
new file mode 100644
index 0000000..15b2b69
--- /dev/null
+++ b/gatekeeperd/tests/gatekeeper_test.cpp
@@ -0,0 +1,204 @@
+/*
+ * Copyright 2015 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#include <gtest/gtest.h>
+#include <UniquePtr.h>
+#include <iostream>
+
+#include <hardware/hw_auth_token.h>
+
+#include "../SoftGateKeeper.h"
+
+using ::gatekeeper::SizedBuffer;
+using ::testing::Test;
+using ::gatekeeper::EnrollRequest;
+using ::gatekeeper::EnrollResponse;
+using ::gatekeeper::VerifyRequest;
+using ::gatekeeper::VerifyResponse;
+using ::gatekeeper::SoftGateKeeper;
+using ::gatekeeper::secure_id_t;
+
+static void do_enroll(SoftGateKeeper &gatekeeper, EnrollResponse *response) {
+    SizedBuffer password;
+
+    password.buffer.reset(new uint8_t[16]);
+    password.length = 16;
+    memset(password.buffer.get(), 0, 16);
+    EnrollRequest request(0, NULL, &password, NULL);
+
+    gatekeeper.Enroll(request, response);
+}
+
+TEST(GateKeeperTest, EnrollSuccess) {
+    SoftGateKeeper gatekeeper;
+    EnrollResponse response;
+    do_enroll(gatekeeper, &response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, response.error);
+}
+
+TEST(GateKeeperTest, EnrollBogusData) {
+    SoftGateKeeper gatekeeper;
+    SizedBuffer password;
+    EnrollResponse response;
+
+    EnrollRequest request(0, NULL, &password, NULL);
+
+    gatekeeper.Enroll(request, &response);
+
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_INVALID, response.error);
+}
+
+TEST(GateKeeperTest, VerifySuccess) {
+    SoftGateKeeper gatekeeper;
+    SizedBuffer provided_password;
+    EnrollResponse enroll_response;
+
+    provided_password.buffer.reset(new uint8_t[16]);
+    provided_password.length = 16;
+    memset(provided_password.buffer.get(), 0, 16);
+
+    do_enroll(gatekeeper, &enroll_response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, enroll_response.error);
+    VerifyRequest request(0, 1, &enroll_response.enrolled_password_handle,
+            &provided_password);
+    VerifyResponse response;
+
+    gatekeeper.Verify(request, &response);
+
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, response.error);
+
+    hw_auth_token_t *auth_token =
+        reinterpret_cast<hw_auth_token_t *>(response.auth_token.buffer.get());
+
+    ASSERT_EQ((uint32_t) HW_AUTH_PASSWORD, ntohl(auth_token->authenticator_type));
+    ASSERT_EQ((uint64_t) 1, auth_token->challenge);
+    ASSERT_NE(~((uint32_t) 0), auth_token->timestamp);
+    ASSERT_NE((uint64_t) 0, auth_token->user_id);
+    ASSERT_NE((uint64_t) 0, auth_token->authenticator_id);
+}
+
+TEST(GateKeeperTest, TrustedReEnroll) {
+    SoftGateKeeper gatekeeper;
+    SizedBuffer provided_password;
+    EnrollResponse enroll_response;
+    SizedBuffer password_handle;
+
+    // do_enroll enrolls an all 0 password
+    provided_password.buffer.reset(new uint8_t[16]);
+    provided_password.length = 16;
+    memset(provided_password.buffer.get(), 0, 16);
+    do_enroll(gatekeeper, &enroll_response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, enroll_response.error);
+
+    // keep a copy of the handle
+    password_handle.buffer.reset(new uint8_t[enroll_response.enrolled_password_handle.length]);
+    password_handle.length = enroll_response.enrolled_password_handle.length;
+    memcpy(password_handle.buffer.get(), enroll_response.enrolled_password_handle.buffer.get(),
+            password_handle.length);
+
+    // verify first password
+    VerifyRequest request(0, 0, &enroll_response.enrolled_password_handle,
+            &provided_password);
+    VerifyResponse response;
+    gatekeeper.Verify(request, &response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, response.error);
+    hw_auth_token_t *auth_token =
+        reinterpret_cast<hw_auth_token_t *>(response.auth_token.buffer.get());
+
+    secure_id_t secure_id = auth_token->user_id;
+
+    // enroll new password
+    provided_password.buffer.reset(new uint8_t[16]);
+    provided_password.length = 16;
+    memset(provided_password.buffer.get(), 0, 16);
+    SizedBuffer password;
+    password.buffer.reset(new uint8_t[16]);
+    memset(password.buffer.get(), 1, 16);
+    password.length = 16;
+    EnrollRequest enroll_request(0, &password_handle, &password, &provided_password);
+    gatekeeper.Enroll(enroll_request, &enroll_response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, enroll_response.error);
+
+    // verify new password
+    password.buffer.reset(new uint8_t[16]);
+    memset(password.buffer.get(), 1, 16);
+    password.length = 16;
+    VerifyRequest new_request(0, 0, &enroll_response.enrolled_password_handle,
+            &password);
+    gatekeeper.Verify(new_request, &response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, response.error);
+    ASSERT_EQ(secure_id,
+        reinterpret_cast<hw_auth_token_t *>(response.auth_token.buffer.get())->user_id);
+}
+
+
+TEST(GateKeeperTest, UntrustedReEnroll) {
+    SoftGateKeeper gatekeeper;
+    SizedBuffer provided_password;
+    EnrollResponse enroll_response;
+
+    // do_enroll enrolls an all 0 password
+    provided_password.buffer.reset(new uint8_t[16]);
+    provided_password.length = 16;
+    memset(provided_password.buffer.get(), 0, 16);
+    do_enroll(gatekeeper, &enroll_response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, enroll_response.error);
+
+    // verify first password
+    VerifyRequest request(0, 0, &enroll_response.enrolled_password_handle,
+            &provided_password);
+    VerifyResponse response;
+    gatekeeper.Verify(request, &response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, response.error);
+    hw_auth_token_t *auth_token =
+        reinterpret_cast<hw_auth_token_t *>(response.auth_token.buffer.get());
+
+    secure_id_t secure_id = auth_token->user_id;
+
+    // enroll new password
+    SizedBuffer password;
+    password.buffer.reset(new uint8_t[16]);
+    memset(password.buffer.get(), 1, 16);
+    password.length = 16;
+    EnrollRequest enroll_request(0, NULL, &password, NULL);
+    gatekeeper.Enroll(enroll_request, &enroll_response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, enroll_response.error);
+
+    // verify new password
+    password.buffer.reset(new uint8_t[16]);
+    memset(password.buffer.get(), 1, 16);
+    password.length = 16;
+    VerifyRequest new_request(0, 0, &enroll_response.enrolled_password_handle,
+            &password);
+    gatekeeper.Verify(new_request, &response);
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_NONE, response.error);
+    ASSERT_NE(secure_id,
+        reinterpret_cast<hw_auth_token_t *>(response.auth_token.buffer.get())->user_id);
+}
+
+
+TEST(GateKeeperTest, VerifyBogusData) {
+    SoftGateKeeper gatekeeper;
+    SizedBuffer provided_password;
+    SizedBuffer password_handle;
+    VerifyResponse response;
+
+    VerifyRequest request(0, 0, &provided_password, &password_handle);
+
+    gatekeeper.Verify(request, &response);
+
+    ASSERT_EQ(::gatekeeper::gatekeeper_error_t::ERROR_INVALID, response.error);
+}