Update monet.

crypto/encryptor.h

+// Copyright (c) 2012 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 CRYPTO_ENCRYPTOR_H_
+#define CRYPTO_ENCRYPTOR_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string_piece.h"
+#include "build/build_config.h"
+#include "crypto/crypto_export.h"
+
+#if defined(USE_NSS_CERTS) || \
+    (!defined(USE_OPENSSL) && (defined(OS_WIN) || defined(OS_MACOSX)))
+#include "crypto/scoped_nss_types.h"
+#endif
+
+namespace crypto {
+
+class SymmetricKey;
+
+class CRYPTO_EXPORT Encryptor {
+ public:
+  enum Mode {
+    CBC,
+    CTR,
+  };
+
+  // This class implements a 128-bits counter to be used in AES-CTR encryption.
+  // Only 128-bits counter is supported in this class.
+  class CRYPTO_EXPORT Counter {
+   public:
+    explicit Counter(const base::StringPiece& counter);
+    ~Counter();
+
+    // Increment the counter value.
+    bool Increment();
+
+    // Write the content of the counter to |buf|. |buf| should have enough
+    // space for |GetLengthInBytes()|.
+    void Write(void* buf);
+
+    // Return the length of this counter.
+    size_t GetLengthInBytes() const;
+
+   private:
+    union {
+      uint32 components32[4];
+      uint64 components64[2];
+    } counter_;
+  };
+
+  Encryptor();
+  virtual ~Encryptor();
+
+  // Initializes the encryptor using |key| and |iv|. Returns false if either the
+  // key or the initialization vector cannot be used.
+  //
+  // If |mode| is CBC, |iv| must not be empty; if it is CTR, then |iv| must be
+  // empty.
+  bool Init(SymmetricKey* key, Mode mode, const base::StringPiece& iv);
+
+  // Encrypts |plaintext| into |ciphertext|.  |plaintext| may only be empty if
+  // the mode is CBC.
+  bool Encrypt(const base::StringPiece& plaintext, std::string* ciphertext);
+
+  // Decrypts |ciphertext| into |plaintext|.  |ciphertext| must not be empty.
+  //
+  // WARNING: In CBC mode, Decrypt() returns false if it detects the padding
+  // in the decrypted plaintext is wrong. Padding errors can result from
+  // tampered ciphertext or a wrong decryption key. But successful decryption
+  // does not imply the authenticity of the data. The caller of Decrypt()
+  // must either authenticate the ciphertext before decrypting it, or take
+  // care to not report decryption failure. Otherwise it could inadvertently
+  // be used as a padding oracle to attack the cryptosystem.
+  bool Decrypt(const base::StringPiece& ciphertext, std::string* plaintext);
+
+  // Sets the counter value when in CTR mode. Currently only 128-bits
+  // counter value is supported.
+  //
+  // Returns true only if update was successful.
+  bool SetCounter(const base::StringPiece& counter);
+
+  // TODO(albertb): Support streaming encryption.
+
+ private:
+  // Generates a mask using |counter_| to be used for encryption in CTR mode.
+  // Resulting mask will be written to |mask| with |mask_len| bytes.
+  //
+  // Make sure there's enough space in mask when calling this method.
+  // Reserve at least |plaintext_len| + 16 bytes for |mask|.
+  //
+  // The generated mask will always have at least |plaintext_len| bytes and
+  // will be a multiple of the counter length.
+  //
+  // This method is used only in CTR mode.
+  //
+  // Returns false if this call failed.
+  bool GenerateCounterMask(size_t plaintext_len,
+                           uint8* mask,
+                           size_t* mask_len);
+
+  // Mask the |plaintext| message using |mask|. The output will be written to
+  // |ciphertext|. |ciphertext| must have at least |plaintext_len| bytes.
+  void MaskMessage(const void* plaintext,
+                   size_t plaintext_len,
+                   const void* mask,
+                   void* ciphertext) const;
+
+  SymmetricKey* key_;
+  Mode mode_;
+  scoped_ptr<Counter> counter_;
+
+#if defined(USE_OPENSSL)
+  bool Crypt(bool do_encrypt,  // Pass true to encrypt, false to decrypt.
+             const base::StringPiece& input,
+             std::string* output);
+  bool CryptCTR(bool do_encrypt,
+                const base::StringPiece& input,
+                std::string* output);
+  std::string iv_;
+#elif defined(USE_NSS_CERTS) || defined(OS_WIN) || defined(OS_MACOSX)
+  bool Crypt(PK11Context* context,
+             const base::StringPiece& input,
+             std::string* output);
+  bool CryptCTR(PK11Context* context,
+                const base::StringPiece& input,
+                std::string* output);
+  ScopedSECItem param_;
+#endif
+};
+
+}  // namespace crypto
+
+#endif  // CRYPTO_ENCRYPTOR_H_