diff --git a/keymaster/4.0/support/Android.bp b/keymaster/4.0/support/Android.bp
index 2f40282..9c5fbab 100644
--- a/keymaster/4.0/support/Android.bp
+++ b/keymaster/4.0/support/Android.bp
@@ -27,11 +27,10 @@
         "authorization_set.cpp",
         "key_param_output.cpp",
         "keymaster_utils.cpp",
-        "Keymaster.cpp",
-        "Keymaster3.cpp",
-        "Keymaster4.cpp",
     ],
-    export_include_dirs: ["include"],
+    export_include_dirs: [
+        "include",
+    ],
     shared_libs: [
         "android.hardware.keymaster@3.0",
         "android.hardware.keymaster@4.0",
@@ -39,6 +38,5 @@
         "libcrypto",
         "libhardware",
         "libhidlbase",
-        "libutils",
-    ]
+    ],
 }
diff --git a/keymaster/4.0/support/Keymaster4.cpp b/keymaster/4.0/support/Keymaster4.cpp
deleted file mode 100644
index cc3d656..0000000
--- a/keymaster/4.0/support/Keymaster4.cpp
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
-**
-** Copyright 2017, 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 <keymasterV4_0/Keymaster4.h>
-
-#include <android-base/logging.h>
-
-namespace android {
-namespace hardware {
-namespace keymaster {
-namespace V4_0 {
-namespace support {
-
-void Keymaster4::getVersionIfNeeded() {
-    if (haveVersion_) return;
-
-    auto rc =
-        dev_->getHardwareInfo([&](SecurityLevel securityLevel, const hidl_string& keymasterName,
-                                  const hidl_string& authorName) {
-            version_ = {keymasterName, authorName, 4 /* major version */, securityLevel,
-                        true /* supportsEc */};
-            haveVersion_ = true;
-        });
-
-    CHECK(rc.isOk()) << "Got error " << rc.description() << " trying to get hardware info";
-}
-
-}  // namespace support
-}  // namespace V4_0
-}  // namespace keymaster
-}  // namespace hardware
-}  // namespace android
diff --git a/keymaster/4.0/support/include/keymasterV4_0/Keymaster4.h b/keymaster/4.0/support/include/keymasterV4_0/Keymaster4.h
deleted file mode 100644
index dfd03ef..0000000
--- a/keymaster/4.0/support/include/keymasterV4_0/Keymaster4.h
+++ /dev/null
@@ -1,160 +0,0 @@
-/*
- **
- ** Copyright 2017, 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 HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_4_H_
-#define HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_4_H_
-
-#include "Keymaster.h"
-
-namespace android {
-namespace hardware {
-namespace keymaster {
-namespace V4_0 {
-namespace support {
-
-using android::sp;
-using IKeymaster4Device = ::android::hardware::keymaster::V4_0::IKeymasterDevice;
-
-class Keymaster4 : public Keymaster {
-   public:
-    using WrappedIKeymasterDevice = IKeymaster4Device;
-    Keymaster4(sp<IKeymasterDevice> km4_dev, const hidl_string& instanceName)
-        : Keymaster(IKeymaster4Device::descriptor, instanceName),
-          haveVersion_(false),
-          dev_(km4_dev) {}
-
-    const VersionResult& halVersion() const override {
-        const_cast<Keymaster4*>(this)->getVersionIfNeeded();
-        return version_;
-    }
-
-    Return<void> getHardwareInfo(getHardwareInfo_cb _hidl_cb) override {
-        return dev_->getHardwareInfo(_hidl_cb);
-    }
-
-    Return<void> getHmacSharingParameters(getHmacSharingParameters_cb _hidl_cb) override {
-        return dev_->getHmacSharingParameters(_hidl_cb);
-    }
-
-    Return<void> computeSharedHmac(const hidl_vec<HmacSharingParameters>& params,
-                                   computeSharedHmac_cb _hidl_cb) override {
-        return dev_->computeSharedHmac(params, _hidl_cb);
-    }
-
-    Return<void> verifyAuthorization(uint64_t operationHandle, const hidl_vec<KeyParameter>& params,
-                                     const HardwareAuthToken& authToken,
-                                     verifyAuthorization_cb _hidl_cb) override {
-        return dev_->verifyAuthorization(operationHandle, params, authToken, _hidl_cb);
-    }
-
-    Return<ErrorCode> addRngEntropy(const hidl_vec<uint8_t>& data) override {
-        return dev_->addRngEntropy(data);
-    }
-
-    Return<void> generateKey(const hidl_vec<KeyParameter>& keyParams,
-                             generateKey_cb _hidl_cb) override {
-        return dev_->generateKey(keyParams, _hidl_cb);
-    }
-
-    Return<void> getKeyCharacteristics(const hidl_vec<uint8_t>& keyBlob,
-                                       const hidl_vec<uint8_t>& clientId,
-                                       const hidl_vec<uint8_t>& appData,
-                                       getKeyCharacteristics_cb _hidl_cb) override {
-        return dev_->getKeyCharacteristics(keyBlob, clientId, appData, _hidl_cb);
-    }
-
-    Return<void> importKey(const hidl_vec<KeyParameter>& params, KeyFormat keyFormat,
-                           const hidl_vec<uint8_t>& keyData, importKey_cb _hidl_cb) override {
-        return dev_->importKey(params, keyFormat, keyData, _hidl_cb);
-    }
-
-    Return<void> importWrappedKey(const hidl_vec<uint8_t>& wrappedKeyData,
-                                  const hidl_vec<uint8_t>& wrappingKeyBlob,
-                                  const hidl_vec<uint8_t>& maskingKey,
-                                  const hidl_vec<KeyParameter>& unwrappingParams,
-                                  uint64_t passwordSid, uint64_t biometricSid,
-                                  importWrappedKey_cb _hidl_cb) {
-        return dev_->importWrappedKey(wrappedKeyData, wrappingKeyBlob, maskingKey, unwrappingParams,
-                                      passwordSid, biometricSid, _hidl_cb);
-    }
-
-    Return<void> exportKey(KeyFormat exportFormat, const hidl_vec<uint8_t>& keyBlob,
-                           const hidl_vec<uint8_t>& clientId, const hidl_vec<uint8_t>& appData,
-                           exportKey_cb _hidl_cb) override {
-        return dev_->exportKey(exportFormat, keyBlob, clientId, appData, _hidl_cb);
-    }
-
-    Return<void> attestKey(const hidl_vec<uint8_t>& keyToAttest,
-                           const hidl_vec<KeyParameter>& attestParams,
-                           attestKey_cb _hidl_cb) override {
-        return dev_->attestKey(keyToAttest, attestParams, _hidl_cb);
-    }
-
-    Return<void> upgradeKey(const hidl_vec<uint8_t>& keyBlobToUpgrade,
-                            const hidl_vec<KeyParameter>& upgradeParams,
-                            upgradeKey_cb _hidl_cb) override {
-        return dev_->upgradeKey(keyBlobToUpgrade, upgradeParams, _hidl_cb);
-    }
-
-    Return<ErrorCode> deleteKey(const hidl_vec<uint8_t>& keyBlob) override {
-        return dev_->deleteKey(keyBlob);
-    }
-
-    Return<ErrorCode> deleteAllKeys() override { return dev_->deleteAllKeys(); }
-
-    Return<ErrorCode> destroyAttestationIds() override { return dev_->destroyAttestationIds(); }
-
-    Return<void> begin(KeyPurpose purpose, const hidl_vec<uint8_t>& key,
-                       const hidl_vec<KeyParameter>& inParams, const HardwareAuthToken& authToken,
-                       begin_cb _hidl_cb) override {
-        return dev_->begin(purpose, key, inParams, authToken, _hidl_cb);
-    }
-
-    Return<void> update(uint64_t operationHandle, const hidl_vec<KeyParameter>& inParams,
-                        const hidl_vec<uint8_t>& input, const HardwareAuthToken& authToken,
-                        const VerificationToken& verificationToken, update_cb _hidl_cb) override {
-        return dev_->update(operationHandle, inParams, input, authToken, verificationToken,
-                            _hidl_cb);
-    }
-
-    Return<void> finish(uint64_t operationHandle, const hidl_vec<KeyParameter>& inParams,
-                        const hidl_vec<uint8_t>& input, const hidl_vec<uint8_t>& signature,
-                        const HardwareAuthToken& authToken,
-                        const VerificationToken& verificationToken, finish_cb _hidl_cb) override {
-        return dev_->finish(operationHandle, inParams, input, signature, authToken,
-                            verificationToken, _hidl_cb);
-    }
-
-    Return<ErrorCode> abort(uint64_t operationHandle) override {
-        return dev_->abort(operationHandle);
-    }
-
-   private:
-    void getVersionIfNeeded();
-
-    bool haveVersion_;
-    VersionResult version_;
-    sp<IKeymaster4Device> dev_;
-};
-
-}  // namespace support
-}  // namespace V4_0
-}  // namespace keymaster
-}  // namespace hardware
-}  // namespace android
-
-#endif  // HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_4_H_
diff --git a/keymaster/4.1/default/Android.bp b/keymaster/4.1/default/Android.bp
index b06878b..27297b9 100644
--- a/keymaster/4.1/default/Android.bp
+++ b/keymaster/4.1/default/Android.bp
@@ -31,6 +31,7 @@
         "libhidlbase",
         "libkeymaster4",
         "libkeymaster41",
+        "libkeymaster4_1support",
         "liblog",
         "libutils",
     ],
diff --git a/keymaster/4.1/support/Android.bp b/keymaster/4.1/support/Android.bp
index e4c3d47..bdd0ca8 100644
--- a/keymaster/4.1/support/Android.bp
+++ b/keymaster/4.1/support/Android.bp
@@ -24,6 +24,9 @@
     ],
     srcs: [
         "attestation_record.cpp",
+        "Keymaster.cpp",
+        "Keymaster3.cpp",
+        "Keymaster4.cpp",
     ],
     export_include_dirs: ["include"],
     shared_libs: [
@@ -34,5 +37,10 @@
         "libcrypto",
         "libhidlbase",
         "libkeymaster4support",
+        "libutils",
+    ],
+    export_shared_lib_headers: [
+        "android.hardware.keymaster@4.1",
+        "libkeymaster4support",
     ],
 }
diff --git a/keymaster/4.0/support/Keymaster.cpp b/keymaster/4.1/support/Keymaster.cpp
similarity index 85%
rename from keymaster/4.0/support/Keymaster.cpp
rename to keymaster/4.1/support/Keymaster.cpp
index f20f951..ea6604e 100644
--- a/keymaster/4.0/support/Keymaster.cpp
+++ b/keymaster/4.1/support/Keymaster.cpp
@@ -14,19 +14,18 @@
  ** limitations under the License.
  */
 
-#include <keymasterV4_0/Keymaster.h>
+#include <keymasterV4_1/Keymaster.h>
 
 #include <iomanip>
 
 #include <android-base/logging.h>
 #include <android/hidl/manager/1.2/IServiceManager.h>
-#include <keymasterV4_0/Keymaster3.h>
-#include <keymasterV4_0/Keymaster4.h>
 #include <keymasterV4_0/key_param_output.h>
 #include <keymasterV4_0/keymaster_utils.h>
+#include <keymasterV4_1/Keymaster3.h>
+#include <keymasterV4_1/Keymaster4.h>
 
-namespace android {
-namespace hardware {
+namespace android::hardware {
 
 template <class T>
 std::ostream& operator<<(std::ostream& os, const hidl_vec<T>& vec) {
@@ -57,6 +56,7 @@
 }
 
 namespace keymaster {
+
 namespace V4_0 {
 
 std::ostream& operator<<(std::ostream& os, const HmacSharingParameters& params) {
@@ -66,7 +66,9 @@
     return os;
 }
 
-namespace support {
+}  // namespace V4_0
+
+namespace V4_1::support {
 
 using ::android::sp;
 using ::android::hidl::manager::V1_2::IServiceManager;
@@ -140,14 +142,14 @@
 }
 
 static hidl_vec<HmacSharingParameters> getHmacParameters(
-    const Keymaster::KeymasterSet& keymasters) {
+        const Keymaster::KeymasterSet& keymasters) {
     std::vector<HmacSharingParameters> params_vec;
     params_vec.reserve(keymasters.size());
     for (auto& keymaster : keymasters) {
         if (keymaster->halVersion().majorVersion < 4) continue;
         auto rc = keymaster->getHmacSharingParameters([&](auto error, auto& params) {
-            CHECK(error == ErrorCode::OK)
-                << "Failed to get HMAC parameters from " << *keymaster << " error " << error;
+            CHECK(error == V4_0::ErrorCode::OK)
+                    << "Failed to get HMAC parameters from " << *keymaster << " error " << error;
             params_vec.push_back(params);
         });
         CHECK(rc.isOk()) << "Failed to communicate with " << *keymaster
@@ -169,18 +171,18 @@
         if (keymaster->halVersion().majorVersion < 4) continue;
         LOG(DEBUG) << "Computing HMAC for " << *keymaster;
         auto rc = keymaster->computeSharedHmac(
-            params, [&](ErrorCode error, const hidl_vec<uint8_t>& curSharingCheck) {
-                CHECK(error == ErrorCode::OK)
-                    << "Failed to get HMAC parameters from " << *keymaster << " error " << error;
-                if (firstKeymaster) {
-                    sharingCheck = curSharingCheck;
-                    firstKeymaster = false;
-                }
-                if (curSharingCheck != sharingCheck)
-                    LOG(WARNING) << "HMAC computation failed for " << *keymaster  //
-                                 << " Expected: " << sharingCheck                 //
-                                 << " got: " << curSharingCheck;
-            });
+                params, [&](V4_0::ErrorCode error, const hidl_vec<uint8_t>& curSharingCheck) {
+                    CHECK(error == V4_0::ErrorCode::OK) << "Failed to get HMAC parameters from "
+                                                        << *keymaster << " error " << error;
+                    if (firstKeymaster) {
+                        sharingCheck = curSharingCheck;
+                        firstKeymaster = false;
+                    }
+                    if (curSharingCheck != sharingCheck)
+                        LOG(WARNING) << "HMAC computation failed for " << *keymaster  //
+                                     << " Expected: " << sharingCheck                 //
+                                     << " got: " << curSharingCheck;
+                });
         CHECK(rc.isOk()) << "Failed to communicate with " << *keymaster
                          << " error: " << rc.description();
     }
@@ -190,8 +192,6 @@
     computeHmac(keymasters, getHmacParameters(keymasters));
 }
 
-}  // namespace support
-}  // namespace V4_0
+}  // namespace V4_1::support
 }  // namespace keymaster
-}  // namespace hardware
-}  // namespace android
+}  // namespace android::hardware
diff --git a/keymaster/4.0/support/Keymaster3.cpp b/keymaster/4.1/support/Keymaster3.cpp
similarity index 81%
rename from keymaster/4.0/support/Keymaster3.cpp
rename to keymaster/4.1/support/Keymaster3.cpp
index b2cdbd9..b665689 100644
--- a/keymaster/4.0/support/Keymaster3.cpp
+++ b/keymaster/4.1/support/Keymaster3.cpp
@@ -15,23 +15,19 @@
  ** limitations under the License.
  */
 
-#include <keymasterV4_0/Keymaster3.h>
+#include <keymasterV4_1/Keymaster3.h>
 
 #include <android-base/logging.h>
 #include <keymasterV4_0/keymaster_utils.h>
 
-namespace android {
-namespace hardware {
-namespace keymaster {
-namespace V4_0 {
-namespace support {
+namespace android::hardware::keymaster::V4_1::support {
 
 using android::hardware::details::StatusOf;
 
 namespace {
 
-ErrorCode convert(V3_0::ErrorCode error) {
-    return static_cast<ErrorCode>(error);
+V4_0::ErrorCode convert(V3_0::ErrorCode error) {
+    return static_cast<V4_0::ErrorCode>(error);
 }
 
 V3_0::KeyPurpose convert(KeyPurpose purpose) {
@@ -53,7 +49,7 @@
 
 KeyParameter convert(const V3_0::KeyParameter& param) {
     KeyParameter converted;
-    converted.tag = static_cast<Tag>(param.tag);
+    converted.tag = static_cast<V4_0::Tag>(param.tag);
     static_assert(sizeof(converted.f) == sizeof(param.f), "This function assumes sizes match");
     memcpy(&converted.f, &param.f, sizeof(param.f));
     converted.blob = param.blob;
@@ -89,7 +85,7 @@
         converted[i] = convert(params[i]);
     }
     converted[params.size()].tag = V3_0::Tag::AUTH_TOKEN;
-    converted[params.size()].blob = authToken2HidlVec(authToken);
+    converted[params.size()].blob = V4_0::support::authToken2HidlVec(authToken);
 
     return converted;
 }
@@ -107,16 +103,19 @@
     if (haveVersion_) return;
 
     auto rc = km3_dev_->getHardwareFeatures(
-        [&](bool isSecure, bool supportsEllipticCurve, bool supportsSymmetricCryptography,
-            bool supportsAttestation, bool supportsAllDigests, const hidl_string& keymasterName,
-            const hidl_string& keymasterAuthorName) {
-            version_ = {keymasterName, keymasterAuthorName, 0 /* major version, filled below */,
-                        isSecure ? SecurityLevel::TRUSTED_ENVIRONMENT : SecurityLevel::SOFTWARE,
-                        supportsEllipticCurve};
-            supportsSymmetricCryptography_ = supportsSymmetricCryptography;
-            supportsAttestation_ = supportsAttestation;
-            supportsAllDigests_ = supportsAllDigests;
-        });
+            [&](bool isSecure, bool supportsEllipticCurve, bool supportsSymmetricCryptography,
+                bool supportsAttestation, bool supportsAllDigests, const hidl_string& keymasterName,
+                const hidl_string& keymasterAuthorName) {
+                version_ = {keymasterName,
+                            keymasterAuthorName,
+                            0 /* major version, filled below */,
+                            0 /* minor version */,
+                            isSecure ? SecurityLevel::TRUSTED_ENVIRONMENT : SecurityLevel::SOFTWARE,
+                            supportsEllipticCurve};
+                supportsSymmetricCryptography_ = supportsSymmetricCryptography;
+                supportsAttestation_ = supportsAttestation;
+                supportsAllDigests_ = supportsAllDigests;
+            });
 
     CHECK(rc.isOk()) << "Got error " << rc.description() << " trying to get hardware features";
 
@@ -139,10 +138,10 @@
     return Void();
 }
 
-Return<ErrorCode> Keymaster3::addRngEntropy(const hidl_vec<uint8_t>& data) {
+Return<V4_0::ErrorCode> Keymaster3::addRngEntropy(const hidl_vec<uint8_t>& data) {
     auto rc = km3_dev_->addRngEntropy(data);
     if (!rc.isOk()) {
-        return StatusOf<V3_0::ErrorCode, ErrorCode>(rc);
+        return StatusOf<V3_0::ErrorCode, V4_0::ErrorCode>(rc);
     }
     return convert(rc);
 }
@@ -215,21 +214,21 @@
     return rc;
 }
 
-Return<ErrorCode> Keymaster3::deleteKey(const hidl_vec<uint8_t>& keyBlob) {
+Return<V4_0::ErrorCode> Keymaster3::deleteKey(const hidl_vec<uint8_t>& keyBlob) {
     auto rc = km3_dev_->deleteKey(keyBlob);
-    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, ErrorCode>(rc);
+    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, V4_0::ErrorCode>(rc);
     return convert(rc);
 }
 
-Return<ErrorCode> Keymaster3::deleteAllKeys() {
+Return<V4_0::ErrorCode> Keymaster3::deleteAllKeys() {
     auto rc = km3_dev_->deleteAllKeys();
-    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, ErrorCode>(rc);
+    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, V4_0::ErrorCode>(rc);
     return convert(rc);
 }
 
-Return<ErrorCode> Keymaster3::destroyAttestationIds() {
+Return<V4_0::ErrorCode> Keymaster3::destroyAttestationIds() {
     auto rc = km3_dev_->destroyAttestationIds();
-    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, ErrorCode>(rc);
+    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, V4_0::ErrorCode>(rc);
     return convert(rc);
 }
 
@@ -242,7 +241,7 @@
     };
 
     auto rc =
-        km3_dev_->begin(convert(purpose), key, convertAndAddAuthToken(inParams, authToken), cb);
+            km3_dev_->begin(convert(purpose), key, convertAndAddAuthToken(inParams, authToken), cb);
     rc.isOk();  // move ctor prereq
     return rc;
 }
@@ -256,8 +255,8 @@
         _hidl_cb(convert(error), inputConsumed, convert(outParams), output);
     };
 
-    auto rc =
-        km3_dev_->update(operationHandle, convertAndAddAuthToken(inParams, authToken), input, cb);
+    auto rc = km3_dev_->update(operationHandle, convertAndAddAuthToken(inParams, authToken), input,
+                               cb);
     rc.isOk();  // move ctor prereq
     return rc;
 }
@@ -278,14 +277,10 @@
     return rc;
 }
 
-Return<ErrorCode> Keymaster3::abort(uint64_t operationHandle) {
+Return<V4_0::ErrorCode> Keymaster3::abort(uint64_t operationHandle) {
     auto rc = km3_dev_->abort(operationHandle);
-    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, ErrorCode>(rc);
+    if (!rc.isOk()) return StatusOf<V3_0::ErrorCode, V4_0::ErrorCode>(rc);
     return convert(rc);
 }
 
-}  // namespace support
-}  // namespace V4_0
-}  // namespace keymaster
-}  // namespace hardware
-}  // namespace android
+}  // namespace android::hardware::keymaster::V4_1::support
diff --git a/keymaster/4.1/support/Keymaster4.cpp b/keymaster/4.1/support/Keymaster4.cpp
new file mode 100644
index 0000000..33f4bb1
--- /dev/null
+++ b/keymaster/4.1/support/Keymaster4.cpp
@@ -0,0 +1,41 @@
+/*
+** Copyright 2017, 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 <keymasterV4_1/Keymaster4.h>
+
+#include <android-base/logging.h>
+
+namespace android::hardware::keymaster::V4_1::support {
+
+void Keymaster4::getVersionIfNeeded() {
+    if (haveVersion_) return;
+
+    auto rc = km4_0_dev_->getHardwareInfo([&](SecurityLevel securityLevel,
+                                              const hidl_string& keymasterName,
+                                              const hidl_string& authorName) {
+        version_ = {keymasterName,
+                    authorName,
+                    4 /* major version */,
+                    static_cast<uint8_t>((km4_1_dev_) ? 1 : 0) /* minor version */,
+                    securityLevel,
+                    true /* supportsEc */};
+        haveVersion_ = true;
+    });
+
+    CHECK(rc.isOk()) << "Got error " << rc.description() << " trying to get hardware info";
+}
+
+}  // namespace android::hardware::keymaster::V4_1::support
diff --git a/keymaster/4.0/support/include/keymasterV4_0/Keymaster.h b/keymaster/4.1/support/include/keymasterV4_1/Keymaster.h
similarity index 73%
rename from keymaster/4.0/support/include/keymasterV4_0/Keymaster.h
rename to keymaster/4.1/support/include/keymasterV4_1/Keymaster.h
index ad83f17..1f49e18 100644
--- a/keymaster/4.0/support/include/keymasterV4_0/Keymaster.h
+++ b/keymaster/4.1/support/include/keymasterV4_1/Keymaster.h
@@ -15,28 +15,28 @@
  ** limitations under the License.
  */
 
-#ifndef HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_H_
-#define HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_H_
-
-#include <android/hardware/keymaster/4.0/IKeymasterDevice.h>
+#pragma once
 
 #include <memory>
 #include <vector>
 
-namespace android {
-namespace hardware {
-namespace keymaster {
-namespace V4_0 {
-namespace support {
+#include <android/hardware/keymaster/4.1/IKeymasterDevice.h>
+#include <keymasterV4_1/keymaster_tags.h>
+
+namespace android::hardware::keymaster::V4_1::support {
 
 /**
- * Keymaster abstracts the underlying V4_0::IKeymasterDevice.  There is one implementation
- * (Keymaster4) which is a trivial passthrough and one that wraps a V3_0::IKeymasterDevice.
+ * Keymaster abstracts the underlying V4_1::IKeymasterDevice.  There are two implementations,
+ * Keymaster3 which wraps a V3_0::IKeymasterDevice and Keymaster4, which wraps either a
+ * V4_0::IKeymasterDevice or a V4_1::IKeymasterDevice.  There is a V3_0::IKeymasterDevice
+ * implementation that is used to wrap pre-HIDL keymaster implementations, and Keymaster3 will wrap
+ * that.
  *
  * The reason for adding this additional layer, rather than simply using the latest HAL directly and
  * subclassing it to wrap any older HAL, is because this provides a place to put additional methods
  * which clients can use when they need to distinguish between different underlying HAL versions,
- * while still having to use only the latest interface.
+ * while still having to use only the latest interface.  Plus it's a handy place to keep some
+ * convenience methods.
  */
 class Keymaster : public IKeymasterDevice {
   public:
@@ -50,12 +50,14 @@
         hidl_string keymasterName;
         hidl_string authorName;
         uint8_t majorVersion;
+        uint8_t minorVersion;
         SecurityLevel securityLevel;
         bool supportsEc;
 
         bool operator>(const VersionResult& other) const {
-            auto lhs = std::tie(securityLevel, majorVersion, supportsEc);
-            auto rhs = std::tie(other.securityLevel, other.majorVersion, other.supportsEc);
+            auto lhs = std::tie(securityLevel, majorVersion, minorVersion, supportsEc);
+            auto rhs = std::tie(other.securityLevel, other.majorVersion, other.minorVersion,
+                                other.supportsEc);
             return lhs > rhs;
         }
     };
@@ -69,6 +71,9 @@
      * There are no side effects otherwise.
      */
     void logIfKeymasterVendorError(ErrorCode ec) const;
+    void logIfKeymasterVendorError(V4_0::ErrorCode ec) const {
+        logIfKeymasterVendorError(static_cast<ErrorCode>(ec));
+    }
 
     /**
      * Returns all available Keymaster3 and Keymaster4 instances, in order of most secure to least
@@ -93,10 +98,4 @@
 
 std::ostream& operator<<(std::ostream& os, const Keymaster& keymaster);
 
-}  // namespace support
-}  // namespace V4_0
-}  // namespace keymaster
-}  // namespace hardware
-}  // namespace android
-
-#endif  // HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_H_
+}  // namespace android::hardware::keymaster::V4_1::support
diff --git a/keymaster/4.0/support/include/keymasterV4_0/Keymaster3.h b/keymaster/4.1/support/include/keymasterV4_1/Keymaster3.h
similarity index 72%
rename from keymaster/4.0/support/include/keymasterV4_0/Keymaster3.h
rename to keymaster/4.1/support/include/keymasterV4_1/Keymaster3.h
index c40be7c..c201e8c 100644
--- a/keymaster/4.0/support/include/keymasterV4_0/Keymaster3.h
+++ b/keymaster/4.1/support/include/keymasterV4_1/Keymaster3.h
@@ -1,5 +1,4 @@
 /*
- **
  ** Copyright 2017, The Android Open Source Project
  **
  ** Licensed under the Apache License, Version 2.0 (the "License");
@@ -15,18 +14,14 @@
  ** limitations under the License.
  */
 
-#ifndef HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_3_H_
-#define HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_3_H_
+#pragma once
 
 #include <android/hardware/keymaster/3.0/IKeymasterDevice.h>
 
 #include "Keymaster.h"
+#include "Operation.h"
 
-namespace android {
-namespace hardware {
-namespace keymaster {
-namespace V4_0 {
-namespace support {
+namespace android::hardware::keymaster::V4_1::support {
 
 using IKeymaster3Device = ::android::hardware::keymaster::V3_0::IKeymasterDevice;
 
@@ -38,8 +33,10 @@
 using ::android::hardware::details::return_status;
 
 class Keymaster3 : public Keymaster {
-   public:
+  public:
+    // This definition is used for device enumeration.
     using WrappedIKeymasterDevice = IKeymaster3Device;
+
     Keymaster3(sp<IKeymaster3Device> km3_dev, const hidl_string& instanceName)
         : Keymaster(IKeymaster3Device::descriptor, instanceName),
           km3_dev_(km3_dev),
@@ -53,24 +50,24 @@
     Return<void> getHardwareInfo(getHardwareInfo_cb _hidl_cb);
 
     Return<void> getHmacSharingParameters(getHmacSharingParameters_cb _hidl_cb) override {
-        _hidl_cb(ErrorCode::UNIMPLEMENTED, {});
+        _hidl_cb(V4_0::ErrorCode::UNIMPLEMENTED, {});
         return Void();
     }
 
     Return<void> computeSharedHmac(const hidl_vec<HmacSharingParameters>&,
                                    computeSharedHmac_cb _hidl_cb) override {
-        _hidl_cb(ErrorCode::UNIMPLEMENTED, {});
+        _hidl_cb(V4_0::ErrorCode::UNIMPLEMENTED, {});
         return Void();
     }
 
     Return<void> verifyAuthorization(uint64_t, const hidl_vec<KeyParameter>&,
                                      const HardwareAuthToken&,
                                      verifyAuthorization_cb _hidl_cb) override {
-        _hidl_cb(ErrorCode::UNIMPLEMENTED, {});
+        _hidl_cb(V4_0::ErrorCode::UNIMPLEMENTED, {});
         return Void();
     }
 
-    Return<ErrorCode> addRngEntropy(const hidl_vec<uint8_t>& data) override;
+    Return<V4_0::ErrorCode> addRngEntropy(const hidl_vec<uint8_t>& data) override;
     Return<void> generateKey(const hidl_vec<KeyParameter>& keyParams,
                              generateKey_cb _hidl_cb) override;
     Return<void> getKeyCharacteristics(const hidl_vec<uint8_t>& keyBlob,
@@ -86,7 +83,7 @@
                                   const hidl_vec<KeyParameter>& /* unwrappingParams */,
                                   uint64_t /* passwordSid */, uint64_t /* biometricSid */,
                                   importWrappedKey_cb _hidl_cb) {
-        _hidl_cb(ErrorCode::UNIMPLEMENTED, {}, {});
+        _hidl_cb(V4_0::ErrorCode::UNIMPLEMENTED, {}, {});
         return Void();
     }
 
@@ -99,9 +96,9 @@
     Return<void> upgradeKey(const hidl_vec<uint8_t>& keyBlobToUpgrade,
                             const hidl_vec<KeyParameter>& upgradeParams,
                             upgradeKey_cb _hidl_cb) override;
-    Return<ErrorCode> deleteKey(const hidl_vec<uint8_t>& keyBlob) override;
-    Return<ErrorCode> deleteAllKeys() override;
-    Return<ErrorCode> destroyAttestationIds() override;
+    Return<V4_0::ErrorCode> deleteKey(const hidl_vec<uint8_t>& keyBlob) override;
+    Return<V4_0::ErrorCode> deleteAllKeys() override;
+    Return<V4_0::ErrorCode> destroyAttestationIds() override;
     Return<void> begin(KeyPurpose purpose, const hidl_vec<uint8_t>& key,
                        const hidl_vec<KeyParameter>& inParams, const HardwareAuthToken& authToken,
                        begin_cb _hidl_cb) override;
@@ -112,9 +109,31 @@
                         const hidl_vec<uint8_t>& input, const hidl_vec<uint8_t>& signature,
                         const HardwareAuthToken& authToken,
                         const VerificationToken& verificationToken, finish_cb _hidl_cb) override;
-    Return<ErrorCode> abort(uint64_t operationHandle) override;
+    Return<V4_0::ErrorCode> abort(uint64_t operationHandle) override;
 
-   private:
+    /**********************************
+     * V4_1::IKeymasterDevice methods *
+     *********************************/
+
+    Return<ErrorCode> deviceLocked(bool /* passwordOnly */,
+                                   const VerificationToken& /* verificationToken */) override {
+        return ErrorCode::UNIMPLEMENTED;
+    }
+
+    Return<ErrorCode> earlyBootEnded() override { return ErrorCode::UNIMPLEMENTED; }
+
+    Return<void> beginOp(KeyPurpose purpose, const hidl_vec<uint8_t>& keyBlob,
+                         const hidl_vec<KeyParameter>& inParams, const HardwareAuthToken& authToken,
+                         beginOp_cb _hidl_cb) override {
+        return begin(purpose, keyBlob, inParams, authToken,
+                     [&_hidl_cb](V4_0::ErrorCode errorCode, const hidl_vec<KeyParameter>& outParams,
+                                 OperationHandle operationHandle) {
+                         _hidl_cb(static_cast<ErrorCode>(errorCode), outParams,
+                                  new Operation(operationHandle));
+                     });
+    }
+
+  private:
     void getVersionIfNeeded();
 
     sp<IKeymaster3Device> km3_dev_;
@@ -126,10 +145,4 @@
     bool supportsAllDigests_;
 };
 
-}  // namespace support
-}  // namespace V4_0
-}  // namespace keymaster
-}  // namespace hardware
-}  // namespace android
-
-#endif  // HARDWARE_INTERFACES_KEYMASTER_40_SUPPORT_KEYMASTER_3_H_
+}  // namespace android::hardware::keymaster::V4_1::support
diff --git a/keymaster/4.1/support/include/keymasterV4_1/Keymaster4.h b/keymaster/4.1/support/include/keymasterV4_1/Keymaster4.h
new file mode 100644
index 0000000..6d74d98
--- /dev/null
+++ b/keymaster/4.1/support/include/keymasterV4_1/Keymaster4.h
@@ -0,0 +1,197 @@
+/*
+ ** Copyright 2020, 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.
+ */
+
+#pragma once
+
+#include "Keymaster.h"
+#include "Operation.h"
+
+namespace android::hardware::keymaster::V4_1::support {
+
+using android::sp;
+
+/**
+ * This class can wrap either a V4_0 or V4_1 IKeymasterDevice.
+ */
+class Keymaster4 : public Keymaster {
+  public:
+    // This definition is used for device enumeration; enumerating 4.0 devices will also
+    // enumerate 4.1. devices.
+    using WrappedIKeymasterDevice = V4_0::IKeymasterDevice;
+
+    Keymaster4(sp<V4_1::IKeymasterDevice> km4_1_dev, const hidl_string& instanceName)
+        : Keymaster(V4_1::IKeymasterDevice::descriptor, instanceName),
+          haveVersion_(false),
+          km4_0_dev_(km4_1_dev),
+          km4_1_dev_(km4_1_dev) {}
+
+    Keymaster4(sp<V4_0::IKeymasterDevice> km4_0_dev, const hidl_string& instanceName)
+        : Keymaster(V4_1::IKeymasterDevice::descriptor, instanceName),
+          haveVersion_(false),
+          km4_0_dev_(km4_0_dev),
+          km4_1_dev_() {}
+
+    const VersionResult& halVersion() const override {
+        const_cast<Keymaster4*>(this)->getVersionIfNeeded();
+        return version_;
+    }
+
+    /**********************************
+     * V4_0::IKeymasterDevice methods *
+     *********************************/
+
+    Return<void> getHardwareInfo(getHardwareInfo_cb _hidl_cb) override {
+        return km4_0_dev_->getHardwareInfo(_hidl_cb);
+    }
+
+    Return<void> getHmacSharingParameters(getHmacSharingParameters_cb _hidl_cb) override {
+        return km4_0_dev_->getHmacSharingParameters(_hidl_cb);
+    }
+
+    Return<void> computeSharedHmac(const hidl_vec<HmacSharingParameters>& params,
+                                   computeSharedHmac_cb _hidl_cb) override {
+        return km4_0_dev_->computeSharedHmac(params, _hidl_cb);
+    }
+
+    Return<void> verifyAuthorization(uint64_t operationHandle, const hidl_vec<KeyParameter>& params,
+                                     const HardwareAuthToken& authToken,
+                                     verifyAuthorization_cb _hidl_cb) override {
+        return km4_0_dev_->verifyAuthorization(operationHandle, params, authToken, _hidl_cb);
+    }
+
+    Return<V4_0::ErrorCode> addRngEntropy(const hidl_vec<uint8_t>& data) override {
+        return km4_0_dev_->addRngEntropy(data);
+    }
+
+    Return<void> generateKey(const hidl_vec<KeyParameter>& keyParams,
+                             generateKey_cb _hidl_cb) override {
+        return km4_0_dev_->generateKey(keyParams, _hidl_cb);
+    }
+
+    Return<void> getKeyCharacteristics(const hidl_vec<uint8_t>& keyBlob,
+                                       const hidl_vec<uint8_t>& clientId,
+                                       const hidl_vec<uint8_t>& appData,
+                                       getKeyCharacteristics_cb _hidl_cb) override {
+        return km4_0_dev_->getKeyCharacteristics(keyBlob, clientId, appData, _hidl_cb);
+    }
+
+    Return<void> importKey(const hidl_vec<KeyParameter>& params, KeyFormat keyFormat,
+                           const hidl_vec<uint8_t>& keyData, importKey_cb _hidl_cb) override {
+        return km4_0_dev_->importKey(params, keyFormat, keyData, _hidl_cb);
+    }
+
+    Return<void> importWrappedKey(const hidl_vec<uint8_t>& wrappedKeyData,
+                                  const hidl_vec<uint8_t>& wrappingKeyBlob,
+                                  const hidl_vec<uint8_t>& maskingKey,
+                                  const hidl_vec<KeyParameter>& unwrappingParams,
+                                  uint64_t passwordSid, uint64_t biometricSid,
+                                  importWrappedKey_cb _hidl_cb) {
+        return km4_0_dev_->importWrappedKey(wrappedKeyData, wrappingKeyBlob, maskingKey,
+                                            unwrappingParams, passwordSid, biometricSid, _hidl_cb);
+    }
+
+    Return<void> exportKey(KeyFormat exportFormat, const hidl_vec<uint8_t>& keyBlob,
+                           const hidl_vec<uint8_t>& clientId, const hidl_vec<uint8_t>& appData,
+                           exportKey_cb _hidl_cb) override {
+        return km4_0_dev_->exportKey(exportFormat, keyBlob, clientId, appData, _hidl_cb);
+    }
+
+    Return<void> attestKey(const hidl_vec<uint8_t>& keyToAttest,
+                           const hidl_vec<KeyParameter>& attestParams,
+                           attestKey_cb _hidl_cb) override {
+        return km4_0_dev_->attestKey(keyToAttest, attestParams, _hidl_cb);
+    }
+
+    Return<void> upgradeKey(const hidl_vec<uint8_t>& keyBlobToUpgrade,
+                            const hidl_vec<KeyParameter>& upgradeParams,
+                            upgradeKey_cb _hidl_cb) override {
+        return km4_0_dev_->upgradeKey(keyBlobToUpgrade, upgradeParams, _hidl_cb);
+    }
+
+    Return<V4_0::ErrorCode> deleteKey(const hidl_vec<uint8_t>& keyBlob) override {
+        return km4_0_dev_->deleteKey(keyBlob);
+    }
+
+    Return<V4_0::ErrorCode> deleteAllKeys() override { return km4_0_dev_->deleteAllKeys(); }
+
+    Return<V4_0::ErrorCode> destroyAttestationIds() override {
+        return km4_0_dev_->destroyAttestationIds();
+    }
+
+    Return<void> begin(KeyPurpose purpose, const hidl_vec<uint8_t>& key,
+                       const hidl_vec<KeyParameter>& inParams, const HardwareAuthToken& authToken,
+                       begin_cb _hidl_cb) override {
+        return km4_0_dev_->begin(purpose, key, inParams, authToken, _hidl_cb);
+    }
+
+    Return<void> update(uint64_t operationHandle, const hidl_vec<KeyParameter>& inParams,
+                        const hidl_vec<uint8_t>& input, const HardwareAuthToken& authToken,
+                        const VerificationToken& verificationToken, update_cb _hidl_cb) override {
+        return km4_0_dev_->update(operationHandle, inParams, input, authToken, verificationToken,
+                                  _hidl_cb);
+    }
+
+    Return<void> finish(uint64_t operationHandle, const hidl_vec<KeyParameter>& inParams,
+                        const hidl_vec<uint8_t>& input, const hidl_vec<uint8_t>& signature,
+                        const HardwareAuthToken& authToken,
+                        const VerificationToken& verificationToken, finish_cb _hidl_cb) override {
+        return km4_0_dev_->finish(operationHandle, inParams, input, signature, authToken,
+                                  verificationToken, _hidl_cb);
+    }
+
+    Return<V4_0::ErrorCode> abort(uint64_t operationHandle) override {
+        return km4_0_dev_->abort(operationHandle);
+    }
+
+    /**********************************
+     * V4_1::IKeymasterDevice methods *
+     *********************************/
+
+    Return<ErrorCode> deviceLocked(bool passwordOnly,
+                                   const VerificationToken& verificationToken) override {
+        if (km4_1_dev_) return km4_1_dev_->deviceLocked(passwordOnly, verificationToken);
+        return ErrorCode::UNIMPLEMENTED;
+    }
+
+    Return<ErrorCode> earlyBootEnded() override {
+        if (km4_1_dev_) return km4_1_dev_->earlyBootEnded();
+        return ErrorCode::UNIMPLEMENTED;
+    }
+
+    Return<void> beginOp(KeyPurpose purpose, const hidl_vec<uint8_t>& keyBlob,
+                         const hidl_vec<KeyParameter>& inParams, const HardwareAuthToken& authToken,
+                         beginOp_cb _hidl_cb) override {
+        if (km4_1_dev_) return km4_1_dev_->beginOp(purpose, keyBlob, inParams, authToken, _hidl_cb);
+
+        return km4_0_dev_->begin(
+                purpose, keyBlob, inParams, authToken,
+                [&_hidl_cb](V4_0::ErrorCode errorCode, const hidl_vec<KeyParameter>& outParams,
+                            OperationHandle operationHandle) {
+                    _hidl_cb(static_cast<ErrorCode>(errorCode), outParams,
+                             new Operation(operationHandle));
+                });
+    }
+
+  private:
+    void getVersionIfNeeded();
+
+    bool haveVersion_;
+    VersionResult version_;
+    sp<V4_0::IKeymasterDevice> km4_0_dev_;
+    sp<V4_1::IKeymasterDevice> km4_1_dev_;
+};  // namespace android::hardware::keymaster::V4_1::support
+
+}  // namespace android::hardware::keymaster::V4_1::support
diff --git a/keymaster/4.1/support/include/keymasterV4_1/Operation.h b/keymaster/4.1/support/include/keymasterV4_1/Operation.h
new file mode 100644
index 0000000..902d49a
--- /dev/null
+++ b/keymaster/4.1/support/include/keymasterV4_1/Operation.h
@@ -0,0 +1,38 @@
+/*
+ ** Copyright 2020, 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.
+ */
+
+#pragma once
+
+#include <android/hardware/keymaster/4.1/IOperation.h>
+
+#include <keymasterV4_1/keymaster_tags.h>
+
+namespace android::hardware::keymaster::V4_1::support {
+
+class Operation : public IOperation {
+  public:
+    Operation(OperationHandle handle) : handle_(handle) {}
+
+    Return<void> getOperationChallenge(getOperationChallenge_cb _hidl_cb) override {
+        _hidl_cb(V4_1::ErrorCode::OK, handle_);
+        return Void();
+    }
+
+  private:
+    OperationHandle handle_;
+};
+
+}  // namespace android::hardware::keymaster::V4_1::support
diff --git a/keymaster/4.1/support/include/keymasterV4_1/authorization_set.h b/keymaster/4.1/support/include/keymasterV4_1/authorization_set.h
index afc0eaf..01605b7 100644
--- a/keymaster/4.1/support/include/keymasterV4_1/authorization_set.h
+++ b/keymaster/4.1/support/include/keymasterV4_1/authorization_set.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef HARDWARE_INTERFACES_KEYMASTER_V4_1_SUPPORT_INCLUDE_AUTHORIZATION_SET_H_
-#define HARDWARE_INTERFACES_KEYMASTER_V4_1_SUPPORT_INCLUDE_AUTHORIZATION_SET_H_
+#pragma once
 
 #include <keymasterV4_0/authorization_set.h>
 
@@ -28,5 +27,3 @@
 using V4_0::KeyParameter;
 
 }  // namespace android::hardware::keymaster::V4_1
-
-#endif  // HARDWARE_INTERFACES_KEYMASTER_V4_1_SUPPORT_INCLUDE_AUTHORIZATION_SET_H_
diff --git a/keymaster/4.1/support/include/keymasterV4_1/keymaster_tags.h b/keymaster/4.1/support/include/keymasterV4_1/keymaster_tags.h
index a90ad8e..c5ce950 100644
--- a/keymaster/4.1/support/include/keymasterV4_1/keymaster_tags.h
+++ b/keymaster/4.1/support/include/keymasterV4_1/keymaster_tags.h
@@ -23,19 +23,26 @@
 
 namespace android::hardware::keymaster::V4_1 {
 
+using V4_0::Algorithm;
 using V4_0::BlockMode;
 using V4_0::Digest;
 using V4_0::EcCurve;
+using V4_0::HardwareAuthenticatorType;
 using V4_0::HardwareAuthToken;
+using V4_0::HmacSharingParameters;
+using V4_0::KeyBlobUsageRequirements;
 using V4_0::KeyCharacteristics;
+using V4_0::KeyFormat;
 using V4_0::KeyOrigin;
 using V4_0::KeyParameter;
 using V4_0::KeyPurpose;
+using V4_0::OperationHandle;
 using V4_0::PaddingMode;
 using V4_0::SecurityLevel;
 using V4_0::TagType;
 using V4_0::VerificationToken;
 
+using V4_0::NullOr;
 using V4_0::TypedTag;
 
 using V4_0::TAG_ACTIVE_DATETIME;
diff --git a/keymaster/4.1/support/include/keymasterV4_1/keymaster_utils.h b/keymaster/4.1/support/include/keymasterV4_1/keymaster_utils.h
new file mode 100644
index 0000000..2e28002
--- /dev/null
+++ b/keymaster/4.1/support/include/keymasterV4_1/keymaster_utils.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#pragma once
+
+#include <keymasterV4_0/keymaster_utils.h>
+
+namespace android::hardware::keymaster::V4_1::support {
+
+using V4_0::support::blob2hidlVec;
+using V4_0::support::hidlVec2AuthToken;
+
+}  // namespace android::hardware::keymaster::V4_1::support