diff --git a/identity/1.0/default/WritableIdentityCredential.h b/identity/1.0/default/WritableIdentityCredential.h
new file mode 100644
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+++ b/identity/1.0/default/WritableIdentityCredential.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2019, 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 ANDROID_HARDWARE_IDENTITY_WRITABLEIDENTITYCREDENTIAL_H
+#define ANDROID_HARDWARE_IDENTITY_WRITABLEIDENTITYCREDENTIAL_H
+
+#include <android/hardware/identity/1.0/IWritableIdentityCredential.h>
+
+#include <android/hardware/identity/support/IdentityCredentialSupport.h>
+
+#include <cppbor.h>
+
+namespace android {
+namespace hardware {
+namespace identity {
+namespace implementation {
+
+using ::std::string;
+using ::std::vector;
+
+using ::android::hardware::hidl_string;
+using ::android::hardware::hidl_vec;
+using ::android::hardware::Return;
+using ::android::hardware::Void;
+using ::android::hardware::identity::V1_0::IWritableIdentityCredential;
+using ::android::hardware::identity::V1_0::Result;
+using ::android::hardware::identity::V1_0::ResultCode;
+using ::android::hardware::identity::V1_0::SecureAccessControlProfile;
+
+class WritableIdentityCredential : public IWritableIdentityCredential {
+  public:
+    WritableIdentityCredential(const hidl_string& docType, bool testCredential)
+        : docType_(docType), testCredential_(testCredential) {}
+
+    // Creates the Credential Key. Returns false on failure. Must be called
+    // right after construction.
+    bool initialize();
+
+    // Methods from ::android::hardware::identity::IWritableIdentityCredential
+    // follow.
+    Return<void> getAttestationCertificate(const hidl_vec<uint8_t>& attestationChallenge,
+                                           getAttestationCertificate_cb _hidl_cb) override;
+
+    Return<void> startPersonalization(uint16_t accessControlProfileCount,
+                                      const hidl_vec<uint16_t>& entryCounts,
+                                      startPersonalization_cb _hidl_cb) override;
+
+    Return<void> addAccessControlProfile(uint16_t id, const hidl_vec<uint8_t>& readerCertificate,
+                                         bool userAuthenticationRequired, uint64_t timeoutMillis,
+                                         uint64_t secureUserId,
+                                         addAccessControlProfile_cb _hidl_cb) override;
+
+    Return<void> beginAddEntry(const hidl_vec<uint16_t>& accessControlProfileIds,
+                               const hidl_string& nameSpace, const hidl_string& name,
+                               uint32_t entrySize, beginAddEntry_cb _hidl_cb) override;
+
+    Return<void> addEntryValue(const hidl_vec<uint8_t>& content,
+                               addEntryValue_cb _hidl_cb) override;
+
+    Return<void> finishAddingEntries(finishAddingEntries_cb _hidl_cb) override;
+
+  private:
+    string docType_;
+    bool testCredential_;
+
+    // These are set in initialize().
+    vector<uint8_t> storageKey_;
+    vector<uint8_t> credentialPrivKey_;
+    vector<uint8_t> credentialPubKey_;
+
+    // These fields are initialized during startPersonalization()
+    size_t numAccessControlProfileRemaining_;
+    vector<uint16_t> remainingEntryCounts_;
+    cppbor::Array signedDataAccessControlProfiles_;
+    cppbor::Map signedDataNamespaces_;
+    cppbor::Array signedDataCurrentNamespace_;
+
+    // These fields are initialized during beginAddEntry()
+    size_t entryRemainingBytes_;
+    vector<uint8_t> entryAdditionalData_;
+    string entryNameSpace_;
+    string entryName_;
+    vector<uint16_t> entryAccessControlProfileIds_;
+    vector<uint8_t> entryBytes_;
+};
+
+}  // namespace implementation
+}  // namespace identity
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_IDENTITY_WRITABLEIDENTITYCREDENTIAL_H