/* Copyright (c) 2008-2009 TrueCrypt Developers Association. All rights reserved. Governed by the TrueCrypt License 3.0 the full text of which is contained in the file License.txt included in TrueCrypt binary and source code distribution packages. */ #ifndef TC_HEADER_Platform_File #define TC_HEADER_Platform_File #include "PlatformBase.h" #include "Buffer.h" #include "FilesystemPath.h" #include "SystemException.h" namespace VeraCrypt { class File { public: enum FileOpenMode { CreateReadWrite, CreateWrite, OpenRead, OpenWrite, OpenReadWrite }; enum FileShareMode { ShareNone, ShareRead, ShareReadWrite, ShareReadWriteIgnoreLock }; enum FileOpenFlags { // Bitmap FlagsNone = 0, PreserveTimestamps = 1 << 0, DisableWriteCaching = 1 << 1 }; #ifdef TC_WINDOWS typedef FILE* SystemFileHandleType; #else typedef int SystemFileHandleType; #endif File () : FileIsOpen (false), SharedHandle (false) { } virtual ~File (); void AssignSystemHandle (SystemFileHandleType openFileHandle, bool sharedHandle = true) { if (FileIsOpen) Close(); FileHandle = openFileHandle; FileIsOpen = true; SharedHandle = sharedHandle; } void Close (); static void Copy (const FilePath &sourcePath, const FilePath &destinationPath, bool preserveTimestamps = true); void Delete (); void Flush () const; uint32 GetDeviceSectorSize () const; static size_t GetOptimalReadSize () { return OptimalReadSize; } static size_t GetOptimalWriteSize () { return OptimalWriteSize; } uint64 GetPartitionDeviceStartOffset () const; bool IsOpen () const { return FileIsOpen; } FilePath GetPath () const; uint64 Length () const; void Open (const FilePath &path, FileOpenMode mode = OpenRead, FileShareMode shareMode = ShareReadWrite, FileOpenFlags flags = FlagsNone); uint64 Read (const BufferPtr &buffer) const; void ReadCompleteBuffer (const BufferPtr &buffer) const; uint64 ReadAt (const BufferPtr &buffer, uint64 position) const; void SeekAt (uint64 position) const; void SeekEnd (int ofset) const; void Write (const ConstBufferPtr &buffer) const; void Write (const ConstBufferPtr &buffer, size_t length) const { Write (buffer.GetRange (0, length)); } void WriteAt (const ConstBufferPtr &buffer, uint64 position) const; protected: void ValidateState () const; static const size_t OptimalReadSize = 256 * 1024; static const size_t OptimalWriteSize = 256 * 1024; bool FileIsOpen; FileOpenFlags mFileOpenFlags; bool SharedHandle; FilePath Path; SystemFileHandleType FileHandle; #ifdef TC_WINDOWS #else time_t AccTime; time_t ModTime; #endif private: File (const File &); File &operator= (const File &); }; } #endif // TC_HEADER_Platform_File b0827e9b74eb8c5400ac4ad20cba9dcb4eaac6c3'>root/doc/html/Hibernation File.html
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<h1>Hibernation File</h1>
<p>Note: The issue described below does not affect you if the system partition or system drive is encrypted<span>*
</span>(for more information, see the chapter <a href="System%20Encryption.html">
<em>System Encryption</em></a>) and if the hibernation file is located on one the partitions within the key scope of system encryption (which it typically is, by default), for example, on the partition where Windows is installed. When the computer hibernates,
 data are encrypted on the fly before they are written to the hibernation file.</p>
<p>When a computer hibernates (or enters a power-saving mode), the content of its system memory is written to a so-called hibernation file on the hard drive. You can configure VeraCrypt (<em>Settings</em> &gt;
<em>Preferences</em> &gt; <em>Dismount all when: Entering power saving mode</em>) to automatically dismount all mounted VeraCrypt volumes, erase their master keys stored in RAM, and cached passwords (stored in RAM), if there are any, before a computer hibernates
 (or enters a power-saving mode). However, keep in mind, that if you do not use system encryption (see the chapter
<a href="System%20Encryption.html"><em>System Encryption</em></a>), VeraCrypt still cannot reliably prevent the contents of sensitive files opened in RAM from being saved unencrypted to a hibernation file. Note that
 when you open a file stored on a VeraCrypt volume, for example, in a text editor, then the content of the file is stored unencrypted in RAM (and it may remain unencrypted in RAM until the computer is turned off).<br>
<br>
Note that when Windows enters Sleep mode, it may be actually configured to enter so-called Hybrid Sleep mode, which involves hibernation. Also note that the operating system may be configured to hibernate or enter the Hybrid Sleep mode when you click or select
 &quot;Shut down&quot; (for more information, please see the documentation for your operating system).<br>
<br>
<strong>To prevent the issues described above</strong>, encrypt the system partition/drive (for information on how to do so, see the chapter
<a href="System%20Encryption.html"><em>System Encryption</em></a>) and make sure that the hibernation file is located on one of the partitions within the key scope of system encryption (which it typically is, by default),
 for example, on the partition where Windows is installed. When the computer hibernates, data will be encrypted on the fly before they are written to the hibernation file.</p>
<p>Note: You may also want to consider creating a hidden operating system (for more information, see the section
<a href="Hidden%20Operating%20System.html">
<em>Hidden Operating System</em></a>)<span>.</span></p>
<p>Alternatively, if you cannot use system encryption, disable or prevent hibernation on your computer at least for each session during which you work with any sensitive data and during which you mount a VeraCrypt volume.</p>
<p><span>* </span>Disclaimer: As Windows XP and Windows 2003 do not provide any API for encryption of hibernation files, VeraCrypt has to modify undocumented components of Windows XP/2003 in order to allow users to encrypt hibernation files. Therefore, VeraCrypt
 cannot guarantee that Windows XP/2003 hibernation files will always be encrypted. In response to our public complaint regarding the missing API, Microsoft began providing a public API for encryption of hibernation files on Windows Vista and later versions
 of Windows. VeraCrypt has used this API and therefore is able to safely encrypt hibernation files under Windows Vista and later versions of Windows. Therefore, if you use Windows XP/2003 and want the hibernation file to be safely encrypted, we strongly recommend
 that you upgrade to Windows Vista or later.</p>
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