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DecryptFile function

Decrypts an encrypted file or directory.

Syntax


BOOL WINAPI DecryptFile(
  _In_        LPCTSTR lpFileName,
  _Reserved_  DWORD dwReserved
);

Parameters

lpFileName [in]

The name of the file or directory to be decrypted.

The caller must have the FILE_READ_DATA, FILE_WRITE_DATA, FILE_READ_ATTRIBUTES, FILE_WRITE_ATTRIBUTES, and SYNCHRONIZE access rights. For more information, see File Security and Access Rights.

dwReserved

Reserved; must be zero.

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

The DecryptFile function requires exclusive access to the file being decrypted, and will fail if another process is using the file. If the file is not encrypted, DecryptFile simply returns a nonzero value, which indicates success.

If lpFileName specifies a read-only file, the function fails and GetLastError returns ERROR_FILE_READ_ONLY. If lpFileName specifies a directory that contains a read-only file, the functions succeeds but the directory is not decrypted.

In Windows 8 and Windows Server 2012, this function is supported by the following technologies.

TechnologySupported

Server Message Block (SMB) 3.0 protocol

Yes

SMB 3.0 Transparent Failover (TFO)

No

SMB 3.0 with Scale-out File Shares (SO)

No

Cluster Shared Volume File System (CsvFS)

No

Resilient File System (ReFS)

No

 

SMB 3.0 does not support EFS on shares with continuous availability capability.

Requirements

Minimum supported client

Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

WinBase.h (include Windows.h)

Library

Advapi32.lib

DLL

Advapi32.dll

Unicode and ANSI names

DecryptFileW (Unicode) and DecryptFileA (ANSI)

See also

CreateFile
EncryptFile
File Encryption
File Management Functions

 

 

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