text: /**
   * @file   crypto_win32.h
   *
   * @section LICENSE
   *
   * The MIT License
   *
   * @copyright Copyright (c) 2018-2020 TileDB, Inc.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   *
   * @section DESCRIPTION
   *
   * This file declares a Win32 crypto interface.
   */
  
  #ifndef TILEDB_CRYPTO_WIN32_H
  #define TILEDB_CRYPTO_WIN32_H
  
  #ifdef _WIN32
  
  #include <windows.h>
  
  #include <bcrypt.h>
  #include "tiledb/common/status.h"
  
  using namespace tiledb::common;
  
  namespace tiledb {
  namespace sm {
  
  class Buffer;
  class ConstBuffer;
  class PreallocatedBuffer;
  
  /** Class encapsulating encryption/decryption using the Win32 CNG interface. */
  class Win32CNG {
   public:
    /**
     * Encrypt the given data using AES-256-GCM.
     *
     * @param key Secret key.
     * @param iv If non-null, the initialization vector to use. It is recommended
     *    to always leave this null.
     * @param input Plaintext to encrypt.
     * @param output Buffer to store encrypted bytes.
     * @param output_iv Buffer to store the IV that was used.
     * @param output_tag Buffer to store the GCM tag that was computed.
     * @return Status
     */
    static Status encrypt_aes256gcm(
        ConstBuffer* key,
        ConstBuffer* iv,
        ConstBuffer* input,
        Buffer* output,
        PreallocatedBuffer* output_iv,
        PreallocatedBuffer* output_tag);
  
    /**
     * Decrypt the given data using AES-256-GCM.
     *
     * @param key Secret key.
     * @param iv The initialization vector to use.
     * @param tag The GCM tag to use.
     * @param input Ciphertext to decrypt.
     * @param output Buffer to store decrypted bytes.
     * @return Status
     */
    static Status decrypt_aes256gcm(
        ConstBuffer* key,
        ConstBuffer* iv,
        ConstBuffer* tag,
        ConstBuffer* input,
        Buffer* output);
  
    /**
     * Compute md5 checksum of data
     *
     * @param input Plaintext to compute hash of
     * @param input_read_size size of input to read for hash
     * @param output Buffer to store store hash bytes.
     * @return Status
     */
    static Status md5(
        const void* input, uint64_t input_read_size, Buffer* output);
  
    /**
     * Compute sha256 checksum of data
     *
     * @param input Plaintext to compute hash of
     * @param input_read_size size of input to read for hash
     * @param output Buffer to store store hash bytes.
     * @return Status
     */
    static Status sha256(
        const void* input, uint64_t input_read_size, Buffer* output);
  
    /**
     *
     * Compute a has using Win32CNG functions
     *
     * @param input Plaintext to compute hash of
     * @param input_read_size size of input to read for hash
     * @param output Buffer to store store hash bytes.
     * @param alg_handle hash algorithm handle
     * @return Status
     */
    static Status hash_bytes(
        const void* input,
        uint64_t input_read_size,
        Buffer* output,
        LPCWSTR hash_algorithm);
  
   private:
    /**
     * Generates a number of cryptographically random bytes.
     *
     * @param num_bytes Number of bytes to generate.
     * @param output Buffer to store random bytes.
     * @return Status
     */
    static Status get_random_bytes(unsigned num_bytes, Buffer* output);
  };
  
  }  // namespace sm
  }  // namespace tiledb
  
  #endif  // _WIN32
  
  #endif
  