Implement the signature verification API.

base/crypto/signature_verifier.h

+// Copyright (c) 2009 The Chromium 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 BASE_CRYPTO_SIGNATURE_VERIFIER_H_
+#define BASE_CRYPTO_SIGNATURE_VERIFIER_H_
+
+#include "build/build_config.h"
+
+#if defined(OS_LINUX)
+#include <cryptoht.h>
+#elif defined(OS_MACOSX)
+#include <Security/cssm.h>
+#elif defined(OS_WIN)
+#include <windows.h>
+#include <wincrypt.h>
+#endif
+
+#include <vector>
+
+#include "base/basictypes.h"
+
+namespace base {
+
+// The SignatureVerifier class verifies a signature using a bare public key
+// (as opposed to a certificate).
+class SignatureVerifier {
+ public:
+  SignatureVerifier();
+  ~SignatureVerifier();
+
+  // Streaming interface:
+
+  // Initiates a signature verification operation.  This should be followed
+  // by one or more VerifyUpdate calls and a VerifyFinal call.
+  //
+  // The signature algorithm is specified as a DER encoded ASN.1
+  // AlgorithmIdentifier structure:
+  //   AlgorithmIdentifier  ::=  SEQUENCE  {
+  //       algorithm               OBJECT IDENTIFIER,
+  //       parameters              ANY DEFINED BY algorithm OPTIONAL  }
+  //
+  // The signature is encoded according to the signature algorithm, but it
+  // must not be further encoded in an ASN.1 BIT STRING.
+  // Note: An RSA signatures is actually a big integer.  It must be in the
+  // big-endian byte order.
+  //
+  // The public key is specified as a DER encoded ASN.1 SubjectPublicKeyInfo
+  // structure, which contains not only the public key but also its type
+  // (algorithm):
+  //   SubjectPublicKeyInfo  ::=  SEQUENCE  {
+  //       algorithm            AlgorithmIdentifier,
+  //       subjectPublicKey     BIT STRING  }
+  bool VerifyInit(const uint8* signature_algorithm,
+                  int signature_algorithm_len,
+                  const uint8* signature,
+                  int signature_len,
+                  const uint8* public_key_info,
+                  int public_key_info_len);
+
+  // Feeds a piece of the data to the signature verifier.
+  void VerifyUpdate(const uint8* data_part, int data_part_len);
+
+  // Concludes a signature verification operation.  Returns true if the
+  // signature is valid.  Returns false if the signature is invalid or an
+  // error occurred.
+  bool VerifyFinal();
+
+  // Note: we can provide a one-shot interface if there is interest:
+  //   bool Verify(const uint8* data,
+  //               int data_len,
+  //               const uint8* signature_algorithm,
+  //               int signature_algorithm_len,
+  //               const uint8* signature,
+  //               int signature_len,
+  //               const uint8* public_key_info,
+  //               int public_key_info_len);
+
+ private:
+  void Reset();
+
+  std::vector<uint8> signature_;
+
+#if defined(OS_LINUX)
+  VFYContext* vfy_context_;
+#elif defined(OS_MACOSX)
+  std::vector<uint8> public_key_info_;
+
+  CSSM_CSP_HANDLE csp_handle_;
+
+  CSSM_CC_HANDLE sig_handle_;
+
+  CSSM_KEY public_key_;
+#elif defined(OS_WIN)
+  HCRYPTPROV provider_;
+
+  HCRYPTHASH hash_object_;
+
+  HCRYPTKEY public_key_;
+#endif
+};
+
+}  // namespace base
+
+#endif  // BASE_CRYPTO_SIGNATURE_VERIFIER_H_