ファイルシステム上のデータを保護する暗号化アドオン機能

#include "FS.h"
void SampleEncryptionFile(void) 
{
  FS_FILE * pFile;
#if FS_SUPPORT_ENCRYPTION
  const U8 aKey[8] = {1, 2, 3, 4}; // Required for encryption
  FS_CRYPT_OBJ CryptObj; // Required for encryption
  static FS_DES_CONTEXT _Context; // Required for encryption
  static int _IsInited; // Required for encryption
#endif // FS_SUPPORT_ENCRYPTION
#if FS_SUPPORT_ENCRYPTION
  //
  // Create the encryption object. It contains all the necessary information
  // for the encryption/decryption of data. This step must be performed only once.
  //
  if (_IsInited == 0) { // Required for encryption
    FS_CRYPT_Prepare(&CryptObj, &FS_CRYPT_ALGO_DES, // Required for encryption
                      &_Context, 512, aKey); // Required for encryption
    _IsInited = 1; // Required for encryption
  }
#endif // FS_SUPPORT_ENCRYPTION
  pFile = FS_FOpen("cipher.bin", "w");
  if (pFile) {
  #if FS_SUPPORT_ENCRYPTION
    //
    // Assign the created encryption object to file handle.
    //
    FS_SetEncryptionObject(pFile, &CryptObj); // Required for encryption
  #endif // FS_SUPPORT_ENCRYPTION
    //
    // Write data to file using encryption.
    //
    FS_Write(pFile, "This message has been encrypted using SEGGER emFile.\n", 53);
    FS_FClose(pFile);
  }
}