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EncryptFile function

Encrypts a file or directory. All data streams in a file are encrypted. All new files created in an encrypted directory are encrypted.

Syntax


BOOL WINAPI EncryptFile(
  _In_  LPCTSTR lpFileName
);

Parameters

lpFileName [in]

The name of the file or directory to be encrypted.

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.

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 EncryptFile function requires exclusive access to the file being encrypted, and will fail if another process is using the file.

If the file is already encrypted, EncryptFile simply returns a nonzero value, which indicates success. If the file is compressed, EncryptFile will decompress the file before encrypting it.

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 encrypted.

To decrypt an encrypted file, use the DecryptFile function.

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 Professional [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

EncryptFileW (Unicode) and EncryptFileA (ANSI)

See also

DecryptFile
File Encryption
File Management Functions

 

 

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