diff --git a/install/include/install/adb_install.h b/install/include/install/adb_install.h
new file mode 100644
index 0000000..dbc8245
--- /dev/null
+++ b/install/include/install/adb_install.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012 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 <recovery_ui/ui.h>
+
+int apply_from_adb(bool* wipe_cache, RecoveryUI* ui);
diff --git a/install/include/install/fuse_sdcard_install.h b/install/include/install/fuse_sdcard_install.h
new file mode 100644
index 0000000..345aea4
--- /dev/null
+++ b/install/include/install/fuse_sdcard_install.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#pragma once
+
+#include "recovery_ui/device.h"
+#include "recovery_ui/ui.h"
+
+int ApplyFromSdcard(Device* device, bool* wipe_cache, RecoveryUI* ui);
diff --git a/install/include/install/install.h b/install/include/install/install.h
new file mode 100644
index 0000000..74fb3d1
--- /dev/null
+++ b/install/include/install/install.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2007 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 <stddef.h>
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include <ziparchive/zip_archive.h>
+
+#include "package.h"
+#include "recovery_ui/ui.h"
+
+enum InstallResult {
+  INSTALL_SUCCESS,
+  INSTALL_ERROR,
+  INSTALL_CORRUPT,
+  INSTALL_NONE,
+  INSTALL_SKIPPED,
+  INSTALL_RETRY,
+  INSTALL_KEY_INTERRUPTED
+};
+
+enum class OtaType {
+  AB,
+  BLOCK,
+  BRICK,
+};
+
+// Installs the given update package. If INSTALL_SUCCESS is returned and *wipe_cache is true on
+// exit, caller should wipe the cache partition.
+int install_package(const std::string& package, bool* wipe_cache, bool needs_mount, int retry_count,
+                    RecoveryUI* ui);
+
+// Verifies the package by ota keys. Returns true if the package is verified successfully,
+// otherwise returns false.
+bool verify_package(Package* package, RecoveryUI* ui);
+
+// Reads meta data file of the package; parses each line in the format "key=value"; and writes the
+// result to |metadata|. Return true if succeed, otherwise return false.
+bool ReadMetadataFromPackage(ZipArchiveHandle zip, std::map<std::string, std::string>* metadata);
+
+// Reads the "recovery.wipe" entry in the zip archive returns a list of partitions to wipe.
+std::vector<std::string> GetWipePartitionList(Package* wipe_package);
+
+// Verifies the compatibility info in a Treble-compatible package. Returns true directly if the
+// entry doesn't exist.
+bool verify_package_compatibility(ZipArchiveHandle package_zip);
+
+// Checks if the the metadata in the OTA package has expected values. Returns 0 on success.
+// Mandatory checks: ota-type, pre-device and serial number(if presents)
+// AB OTA specific checks: pre-build version, fingerprint, timestamp.
+int CheckPackageMetadata(const std::map<std::string, std::string>& metadata, OtaType ota_type);
diff --git a/install/include/install/package.h b/install/include/install/package.h
new file mode 100644
index 0000000..cd44d10
--- /dev/null
+++ b/install/include/install/package.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <ziparchive/zip_archive.h>
+
+#include "verifier.h"
+
+// This class serves as a wrapper for an OTA update package. It aims to provide the common
+// interface for both packages loaded in memory and packages read from fd.
+class Package : public VerifierInterface {
+ public:
+  static std::unique_ptr<Package> CreateMemoryPackage(
+      const std::string& path, const std::function<void(float)>& set_progress);
+  static std::unique_ptr<Package> CreateMemoryPackage(
+      std::vector<uint8_t> content, const std::function<void(float)>& set_progress);
+  static std::unique_ptr<Package> CreateFilePackage(const std::string& path,
+                                                    const std::function<void(float)>& set_progress);
+
+  virtual ~Package() = default;
+
+  // Opens the package as a zip file and returns the ZipArchiveHandle.
+  virtual ZipArchiveHandle GetZipArchiveHandle() = 0;
+
+  // Updates the progress in fraction during package verification.
+  void SetProgress(float progress) override;
+
+ protected:
+  // An optional function to update the progress.
+  std::function<void(float)> set_progress_;
+};
diff --git a/install/include/install/verifier.h b/install/include/install/verifier.h
new file mode 100644
index 0000000..f9e9475
--- /dev/null
+++ b/install/include/install/verifier.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2008 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 <stdint.h>
+
+#include <functional>
+#include <memory>
+#include <vector>
+
+#include <openssl/ec_key.h>
+#include <openssl/rsa.h>
+#include <openssl/sha.h>
+
+constexpr size_t MiB = 1024 * 1024;
+
+using HasherUpdateCallback = std::function<void(const uint8_t* addr, uint64_t size)>;
+
+struct RSADeleter {
+  void operator()(RSA* rsa) const {
+    RSA_free(rsa);
+  }
+};
+
+struct ECKEYDeleter {
+  void operator()(EC_KEY* ec_key) const {
+    EC_KEY_free(ec_key);
+  }
+};
+
+struct Certificate {
+  typedef enum {
+    KEY_TYPE_RSA,
+    KEY_TYPE_EC,
+  } KeyType;
+
+  Certificate(int hash_len_, KeyType key_type_, std::unique_ptr<RSA, RSADeleter>&& rsa_,
+              std::unique_ptr<EC_KEY, ECKEYDeleter>&& ec_)
+      : hash_len(hash_len_), key_type(key_type_), rsa(std::move(rsa_)), ec(std::move(ec_)) {}
+
+  // SHA_DIGEST_LENGTH (SHA-1) or SHA256_DIGEST_LENGTH (SHA-256)
+  int hash_len;
+  KeyType key_type;
+  std::unique_ptr<RSA, RSADeleter> rsa;
+  std::unique_ptr<EC_KEY, ECKEYDeleter> ec;
+};
+
+class VerifierInterface {
+ public:
+  virtual ~VerifierInterface() = default;
+
+  // Returns the package size in bytes.
+  virtual uint64_t GetPackageSize() const = 0;
+
+  // Reads |byte_count| data starting from |offset|, and puts the result in |buffer|.
+  virtual bool ReadFullyAtOffset(uint8_t* buffer, uint64_t byte_count, uint64_t offset) = 0;
+
+  // Updates the hash contexts for |length| bytes data starting from |start|.
+  virtual bool UpdateHashAtOffset(const std::vector<HasherUpdateCallback>& hashers, uint64_t start,
+                                  uint64_t length) = 0;
+
+  // Updates the progress in fraction during package verification.
+  virtual void SetProgress(float progress) = 0;
+};
+
+//  Looks for an RSA signature embedded in the .ZIP file comment given the path to the zip.
+//  Verifies that it matches one of the given public keys. Returns VERIFY_SUCCESS or
+//  VERIFY_FAILURE (if any error is encountered or no key matches the signature).
+int verify_file(VerifierInterface* package, const std::vector<Certificate>& keys);
+
+// Checks that the RSA key has a modulus of 2048 or 4096 bits long, and public exponent is 3 or
+// 65537.
+bool CheckRSAKey(const std::unique_ptr<RSA, RSADeleter>& rsa);
+
+// Checks that the field size of the curve for the EC key is 256 bits.
+bool CheckECKey(const std::unique_ptr<EC_KEY, ECKEYDeleter>& ec_key);
+
+// Parses a PEM-encoded x509 certificate from the given buffer and saves it into |cert|. Returns
+// false if there is a parsing failure or the signature's encryption algorithm is not supported.
+bool LoadCertificateFromBuffer(const std::vector<uint8_t>& pem_content, Certificate* cert);
+
+// Iterates over the zip entries with the suffix "x509.pem" and returns a list of recognized
+// certificates. Returns an empty list if we fail to parse any of the entries.
+std::vector<Certificate> LoadKeysFromZipfile(const std::string& zip_name);
+
+#define VERIFY_SUCCESS 0
+#define VERIFY_FAILURE 1
diff --git a/install/include/private/asn1_decoder.h b/install/include/private/asn1_decoder.h
new file mode 100644
index 0000000..e5337d9
--- /dev/null
+++ b/install/include/private/asn1_decoder.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2013 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 ASN1_DECODER_H_
+#define ASN1_DECODER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+class asn1_context {
+ public:
+  asn1_context(const uint8_t* buffer, size_t length) : p_(buffer), length_(length), app_type_(0) {}
+  int asn1_constructed_type() const;
+  asn1_context* asn1_constructed_get();
+  bool asn1_constructed_skip_all();
+  asn1_context* asn1_sequence_get();
+  asn1_context* asn1_set_get();
+  bool asn1_sequence_next();
+  bool asn1_oid_get(const uint8_t** oid, size_t* length);
+  bool asn1_octet_string_get(const uint8_t** octet_string, size_t* length);
+
+ private:
+  static constexpr int kMaskConstructed = 0xE0;
+  static constexpr int kMaskTag = 0x7F;
+  static constexpr int kMaskAppType = 0x1F;
+
+  static constexpr int kTagOctetString = 0x04;
+  static constexpr int kTagOid = 0x06;
+  static constexpr int kTagSequence = 0x30;
+  static constexpr int kTagSet = 0x31;
+  static constexpr int kTagConstructed = 0xA0;
+
+  int peek_byte() const;
+  int get_byte();
+  bool skip_bytes(size_t num_skip);
+  bool decode_length(size_t* out_len);
+
+  const uint8_t* p_;
+  size_t length_;
+  int app_type_;
+};
+
+#endif /* ASN1_DECODER_H_ */
diff --git a/install/include/private/setup_commands.h b/install/include/private/setup_commands.h
new file mode 100644
index 0000000..7fdc741
--- /dev/null
+++ b/install/include/private/setup_commands.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 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.
+ */
+
+// Private headers exposed for testing purpose only.
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include <ziparchive/zip_archive.h>
+
+// Sets up the commands for a non-A/B update. Extracts the updater binary from the open zip archive
+// |zip| located at |package|. Stores the command line that should be called into |cmd|. The
+// |status_fd| is the file descriptor the child process should use to report back the progress of
+// the update.
+int SetUpNonAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int retry_count,
+                             int status_fd, std::vector<std::string>* cmd);
+
+// Sets up the commands for an A/B update. Extracts the needed entries from the open zip archive
+// |zip| located at |package|. Stores the command line that should be called into |cmd|. The
+// |status_fd| is the file descriptor the child process should use to report back the progress of
+// the update. Note that since this applies to the sideloading flow only, it takes one less
+// parameter |retry_count| than the non-A/B version.
+int SetUpAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int status_fd,
+                          std::vector<std::string>* cmd);