diff --git a/gatekeeper/aidl/software/SoftGateKeeper.h b/gatekeeper/aidl/software/SoftGateKeeper.h
new file mode 100644
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--- /dev/null
+++ b/gatekeeper/aidl/software/SoftGateKeeper.h
@@ -0,0 +1,189 @@
+/*
+ * 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 <openssl/sha.h>
+
+#include <crypto_scrypt.h>
+}
+
+#include <memory>
+#include <unordered_map>
+
+#include <android-base/logging.h>
+#include <android-base/memory.h>
+#include <gatekeeper/gatekeeper.h>
+#include <keymaster/km_openssl/hmac.h>
+
+#include "SharedSecret.h"
+
+namespace gatekeeper {
+
+struct fast_hash_t {
+    uint64_t salt;
+    uint8_t digest[SHA256_DIGEST_LENGTH];
+};
+
+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(const ::aidl::android::hardware::security::sharedsecret::SoftSharedSecret&
+                           shared_secret)
+        : shared_secret_(shared_secret) {
+        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;
+        if (hmac_key_.key_material == nullptr) {
+            hmac_key_ = shared_secret_.HmacKey();
+        }
+        *auth_token_key = hmac_key_.key_material;
+        *length = hmac_key_.key_material_size;
+        return true;
+    }
+
+    virtual void GetPasswordKey(const uint8_t** password_key, uint32_t* length) {
+        if (password_key == NULL || length == NULL) return;
+        *password_key = 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* key,
+                                  uint32_t key_length, const uint8_t* message,
+                                  const uint32_t message_length) const {
+        if (signature == NULL) return;
+        keymaster::HmacSha256 hmac_calculator;
+        if (!hmac_calculator.Init(key, key_length)) {
+            LOG(ERROR) << "ComputeSignature: Failed to initialize hmac calculator";
+            return;
+        }
+        if (!hmac_calculator.Sign(message, message_length, signature, signature_length)) {
+            LOG(ERROR) << "ComputeSignature: failed to create hmac";
+        }
+    }
+
+    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,
+                                  bool /* secure */) {
+        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 bool ClearFailureRecord(uint32_t uid, secure_id_t user_id, bool /* secure */) {
+        failure_record_t* stored = &failure_map_[uid];
+        stored->secure_user_id = user_id;
+        stored->last_checked_timestamp = 0;
+        stored->failure_counter = 0;
+        return true;
+    }
+
+    virtual bool WriteFailureRecord(uint32_t uid, failure_record_t* record, bool /* secure */) {
+        failure_map_[uid] = *record;
+        return true;
+    }
+
+    fast_hash_t ComputeFastHash(const SizedBuffer& password, uint64_t salt) {
+        fast_hash_t fast_hash;
+        size_t digest_size = password.size() + sizeof(salt);
+        std::unique_ptr<uint8_t[]> digest(new uint8_t[digest_size]);
+        memcpy(digest.get(), &salt, sizeof(salt));
+        memcpy(digest.get() + sizeof(salt), password.Data<uint8_t>(), password.size());
+
+        SHA256(digest.get(), digest_size, (uint8_t*)&fast_hash.digest);
+
+        fast_hash.salt = salt;
+        return fast_hash;
+    }
+
+    bool VerifyFast(const fast_hash_t& fast_hash, const SizedBuffer& password) {
+        fast_hash_t computed = ComputeFastHash(password, fast_hash.salt);
+        return memcmp(computed.digest, fast_hash.digest, SHA256_DIGEST_LENGTH) == 0;
+    }
+
+    bool DoVerify(const password_handle_t* expected_handle, const SizedBuffer& password) {
+        uint64_t user_id = android::base::get_unaligned<secure_id_t>(&expected_handle->user_id);
+        FastHashMap::const_iterator it = fast_hash_map_.find(user_id);
+        if (it != fast_hash_map_.end() && VerifyFast(it->second, password)) {
+            return true;
+        } else {
+            if (GateKeeper::DoVerify(expected_handle, password)) {
+                uint64_t salt;
+                GetRandom(&salt, sizeof(salt));
+                fast_hash_map_[user_id] = ComputeFastHash(password, salt);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+  private:
+    typedef std::unordered_map<uint32_t, failure_record_t> FailureRecordMap;
+    typedef std::unordered_map<uint64_t, fast_hash_t> FastHashMap;
+
+    const ::aidl::android::hardware::security::sharedsecret::SoftSharedSecret& shared_secret_;
+    std::unique_ptr<uint8_t[]> key_;
+    FailureRecordMap failure_map_;
+    FastHashMap fast_hash_map_;
+    mutable ::keymaster::KeymasterKeyBlob hmac_key_;
+};
+}  // namespace gatekeeper
+
+#endif  // SOFT_GATEKEEPER_H_