AESFile Manual

Table of Contents

• About
• Allocation/Deallocation
• Open
• Miscellaneous
• Further Reading

About

The class AESFile provides means to create and work with AES encrypted files. Derived from BaseFile working with AES files works exactly the same as with other files, with the only exception of opening the file. So it is recommended to read BaseFile Manual first.

Warning

For encryption using the MAXON API see Stream Conversions Manual.

  // This example demonstrates encrypting a file and comparing the encrypted result with the original file.
 
  // Let user choose a file to encrypt.
  Filename fnInput;
  if (!fnInput.FileSelect(FILESELECTTYPE::ANYTHING, FILESELECT::LOAD, "Open file to encrypt..."_s))
    return maxon::OK;
 
  AutoAlloc<BaseFile> fileInput;
  AutoAlloc<AESFile>  fileAes;
  if (!fileInput || !fileAes)
    return maxon::OutOfMemoryError(MAXON_SOURCE_LOCATION);
 
  // Open the input file.
  if (!fileInput->Open(fnInput, FILEOPEN::READ, FILEDIALOG::ANY, BYTEORDER::V_INTEL, MACTYPE_CINEMA, MACCREATOR_CINEMA))
  {
    return maxon::IoError(MAXON_SOURCE_LOCATION, MaxonConvert(fnInput, MAXONCONVERTMODE::NONE), "Error: Failed to open input file."_s);
  }
 
  Filename fnAes = fnInput;
  fnAes.SetSuffix("aes"_s);
  // Note: Password needs to be either 16, 24, or 32 characters long.
  const char  pw[] = { 's', 'p', 'e', 'a', 'k', ',', ' ', 'f', 'r', 'i', 'e', 'n', 'd', ',', ' ', 'a', 'n', 'd', ' ', 'e', 'n', 't', 'e', 'r' };
  const Int32 keylen = sizeof(pw) * 8;  // keylen is in bits
  DebugAssert((keylen == 128) || (keylen == 192) || (keylen == 256));
  const Int32 blocksize = 256;
  if (!fileAes->Open(fnAes, pw, keylen, blocksize, 0, FILEOPEN::WRITE))
  {
    return maxon::IoError(MAXON_SOURCE_LOCATION, MaxonConvert(fnAes, MAXONCONVERTMODE::NONE), "Error: Failed to open AES file for writing."_s);
  }
 
  const Int fileSize = fileInput->GetLength();
  Char*     buffer = NewMemClear(Char, fileSize) iferr_return;
  const Int readBytes = fileInput->TryReadBytes(buffer, fileSize);
  if (readBytes != fileSize)
  {
    return maxon::UnexpectedError(MAXON_SOURCE_LOCATION, "Error: Failed to read data from input file."_s);
  }
  if (!fileAes->WriteBytes(buffer, fileSize))
  {
    return maxon::UnexpectedError(MAXON_SOURCE_LOCATION, "Error: Failed to write data to AES file."_s);
  }
 
  fileAes->Close();
  fileInput->Close();
 
  // Finally check the encryption result.
  if (AESFile::CheckEncryption(fnAes, fnInput, pw, keylen, blocksize))
  {
    ApplicationOutput("Success: The encrypted file matches the encrypted version."_s);
    return maxon::OK;
  }
  else
  {
    return maxon::UnexpectedError(MAXON_SOURCE_LOCATION, "Error: The encrypted file does not match the encrypted version."_s);
  }

Allocation/Deallocation

AESFile objects are created with the usual tools, see Entity Creation and Destruction Manual (Classic).

• AESFile::Alloc(): Allocates an AESFile.
• AESFile::Free(): Destructs AESFile previously allocated with Alloc().

Open

• AESFile::Open(): Opens an AES encrypted file.

Warning

For a plugin to be cross platform then the type and creator parameters must be correctly filled for Mac.

Miscellaneous

• AESFile::CheckEncryption(): Checks if the encrypted file is the encrypted version of the decrypted file.

Further Reading

• Algorithms
• Stream Conversions Manual
• AES Manual
• BaseFile Manual
• Filename Manual