diff --git a/payload_verifier.h b/payload_verifier.h
new file mode 100644
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--- /dev/null
+++ b/payload_verifier.h
@@ -0,0 +1,77 @@
+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UPDATE_ENGINE_PAYLOAD_VERIFIER_H_
+#define UPDATE_ENGINE_PAYLOAD_VERIFIER_H_
+
+#include <string>
+#include <vector>
+
+#include <base/basictypes.h>
+#include "update_engine/update_metadata.pb.h"
+
+// This class encapsulates methods used for payload signature verification.
+// See payload_generator/payload_signer.h for payload signing.
+
+namespace chromeos_update_engine {
+
+extern const uint32_t kSignatureMessageOriginalVersion;
+extern const uint32_t kSignatureMessageCurrentVersion;
+
+class PayloadVerifier {
+ public:
+  // Returns false if the payload signature can't be verified. Returns true
+  // otherwise and sets |out_hash| to the signed payload hash.
+  static bool VerifySignature(const std::vector<char>& signature_blob,
+                              const std::string& public_key_path,
+                              std::vector<char>* out_hash_data);
+
+  // Interprets signature_blob as a protocol buffer containing the Signatures
+  // message and decrypts the signature data using the public_key_path and
+  // stores the resultant raw hash data in out_hash_data. Returns true if
+  // everything is successful. False otherwise. It also takes the client_version
+  // and interprets the signature blob according to that version.
+  static bool VerifySignatureBlob(const std::vector<char>& signature_blob,
+                                  const std::string& public_key_path,
+                                  uint32_t client_version,
+                                  std::vector<char>* out_hash_data);
+
+  // Decrypts sig_data with the given public_key_path and populates
+  // out_hash_data with the decoded raw hash. Returns true if successful,
+  // false otherwise.
+  static bool GetRawHashFromSignature(const std::vector<char>& sig_data,
+                                      const std::string& public_key_path,
+                                      std::vector<char>* out_hash_data);
+
+  // Returns true if the payload in |payload_path| is signed and its hash can be
+  // verified using the public key in |public_key_path| with the signature
+  // of a given version in the signature blob. Returns false otherwise.
+  static bool VerifySignedPayload(const std::string& payload_path,
+                                  const std::string& public_key_path,
+                                  uint32_t client_key_check_version);
+
+  // Pads a SHA256 hash so that it may be encrypted/signed with RSA2048
+  // using the PKCS#1 v1.5 scheme.
+  // hash should be a pointer to vector of exactly 256 bits. The vector
+  // will be modified in place and will result in having a length of
+  // 2048 bits. Returns true on success, false otherwise.
+  static bool PadRSA2048SHA256Hash(std::vector<char>* hash);
+
+  // Reads the payload from the given |payload_path| into the |out_payload|
+  // vector. It also parses the manifest protobuf in the payload and returns it
+  // in |out_manifest| along with the size of the entire metadata in
+  // |out_metadata_size|.
+  static bool LoadPayload(const std::string& payload_path,
+                          std::vector<char>* out_payload,
+                          DeltaArchiveManifest* out_manifest,
+                          uint64_t* out_metadata_size);
+
+ private:
+  // This should never be constructed
+  DISALLOW_IMPLICIT_CONSTRUCTORS(PayloadVerifier);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_PAYLOAD_VERIFIER_H_