diff --git a/keystore/user_state.h b/keystore/user_state.h
new file mode 100644
index 0000000..2a52f81
--- /dev/null
+++ b/keystore/user_state.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2016 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 KEYSTORE_USER_STATE_H_
+#define KEYSTORE_USER_STATE_H_
+
+#include <sys/types.h>
+
+#include <openssl/aes.h>
+
+#include <utils/String8.h>
+
+#include <keystore/keystore.h>
+
+#include "entropy.h"
+
+class UserState {
+  public:
+    UserState(uid_t userId);
+    ~UserState();
+
+    bool initialize();
+
+    uid_t getUserId() const { return mUserId; }
+    const char* getUserDirName() const { return mUserDir; }
+
+    const char* getMasterKeyFileName() const { return mMasterKeyFile; }
+
+    void setState(State state);
+    State getState() const { return mState; }
+
+    int8_t getRetry() const { return mRetry; }
+
+    void zeroizeMasterKeysInMemory();
+    bool deleteMasterKey();
+
+    ResponseCode initialize(const android::String8& pw, Entropy* entropy);
+
+    ResponseCode copyMasterKey(UserState* src);
+    ResponseCode copyMasterKeyFile(UserState* src);
+    ResponseCode writeMasterKey(const android::String8& pw, Entropy* entropy);
+    ResponseCode readMasterKey(const android::String8& pw, Entropy* entropy);
+
+    AES_KEY* getEncryptionKey() { return &mMasterKeyEncryption; }
+    AES_KEY* getDecryptionKey() { return &mMasterKeyDecryption; }
+
+    bool reset();
+
+  private:
+    static const int MASTER_KEY_SIZE_BYTES = 16;
+    static const int MASTER_KEY_SIZE_BITS = MASTER_KEY_SIZE_BYTES * 8;
+
+    static const int MAX_RETRY = 4;
+    static const size_t SALT_SIZE = 16;
+
+    void generateKeyFromPassword(uint8_t* key, ssize_t keySize, const android::String8& pw,
+                                 uint8_t* salt);
+    bool generateSalt(Entropy* entropy);
+    bool generateMasterKey(Entropy* entropy);
+    void setupMasterKeys();
+
+    uid_t mUserId;
+
+    char* mUserDir;
+    char* mMasterKeyFile;
+
+    State mState;
+    int8_t mRetry;
+
+    uint8_t mMasterKey[MASTER_KEY_SIZE_BYTES];
+    uint8_t mSalt[SALT_SIZE];
+
+    AES_KEY mMasterKeyEncryption;
+    AES_KEY mMasterKeyDecryption;
+};
+
+#endif  // KEYSTORE_USER_STATE_H_