fEncrypt (Function)

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Functions for managing external files

Operating mode in Windows Vista (and later)

Encrypting/Decrypting a character string

Related examples

See also

fEncrypt (Function)

In french: fCrypte

Warning
From version 24, fCrypt is kept for backward compatibility. This function is replaced by fEncrypt.

Encrypts a file in binary or ASCII format.

Remark: This file can be decrypted by fDecrypt.

Example

See additional examples

// Encrypt a file
ResEncrypt = fCrypt("C:\MyDirectories\File.txt", ...
"C:\MyDirectories\EncryptedFile.txt", "Password")

Syntax

<Result> = fEncrypt(<Path of file to encrypt> , <Path of encrypted file> , <Password> [, <Type of encryption> [, <Format of encrypted file>]])

<Result>: Boolean

True if the encryption was performed,
False otherwise. To find out the error details, use ErrorInfo associated with the errMessage constant.

<Path of file to encrypt>: Character string (with quotes)

Name and full (or relative) path of the file to encrypt (up to 260 characters). A UNC path can be used.
Versions 15 and later
This parameter can be in Ansi or Unicode format.
New in version 15
This parameter can be in Ansi or Unicode format.
This parameter can be in Ansi or Unicode format.

<Path of encrypted file>: Character string (with quotes)

Name and full (or relative) path of the encrypted file (up to 260 characters). A UNC path can be used.
Versions 15 and later
This parameter can be in Ansi or Unicode format.
New in version 15
This parameter can be in Ansi or Unicode format.
This parameter can be in Ansi or Unicode format.

<Password>: Character string (with quotes)

Password used to encrypt the file. This password will be used to decrypt the encrypted file (fDecrypt). A long password provides better encryption security.

<Type of encryption>: Optional constant

Indicates the type of encryption:
cryptNone No encryption is performed.
cryptFast
(Default value) Priority is given to the encryption speed (algorithm on 128 bits).
cryptRC516 Priority is given to the encryption security (RC5 algorithm on 16 rounds).
cryptSecure Priority is given to the encryption security (RC5 algorithm on 128 bits).

<Format of encrypted file>: Optional Integer constant

Indicates the format of the encrypted file:
encodePCS or True
(Default value) ASCII format.
The encrypted file will contain printable characters only. The encrypted file will be larger (about 30%) than the initial file.
This format can be used to insert an encrypted file into the email body for example.
encodeNone or False Binary format.
The encrypted file may contain non-printable characters. The file will be larger (about 4 bytes) than the initial file.
encodeBASE64 BASE 64 format.
The file is encrypted with the BASE64 algorithm. The encrypted file will be larger (about 30%) than the initial file.
This format can be used to insert an encrypted file into the email body for example.
encodeUUEncode UUEncode format.
The file is encrypted with the UUEncode algorithm. The encrypted file will be larger (about 30%) than the initial file.
This format can be used to insert an encrypted file into the email body for example.

Remarks

Managing errors

fEncrypt generates an error in the following cases:

the file to encrypt does not exist,
the file to encrypt is locked,
the path of the file to encrypt is invalid,
<Password> is an empty string,
the user has no read rights on the file to encrypt,
the user has no write rights on the encrypted file.

Operating mode in Windows Vista (and later)

If this function does not operate properly in Windows Vista (and later), check whether the file or directory used is not in one of the system directories (Windows directory or "Program Files" directory).

Indeed, in Windows Vista (and later), with the UAC mechanism (User Account Control) enabled, you must have the administrator privileges to handle and/or modify the files or directories in the system directories (Windows directory or "Program Files" directory).

Programming tip: To handle and/or modify the files or directories without administrator privileges, you should:

avoid writing into the Windows directory or into the "Program Files" directory,
use the system directory corresponding to the application (returned by SysDir associated with the srCommonAppData constant).

Remark: In Windows Vista (and later), the virtualization mechanism is used to make the applications compatible with Vista. If the file is created in a system directory without having sufficient rights, this file will actually be created in another directory (C:\Users\<LOGIN>AppData\Local\VirtualStore\Windows\). In this case, the file cannot be shared between several applications.

Encrypting/Decrypting a character string

To encrypt/decrypt a character string, use Encrypt and Decrypt.

Related Examples:

Unit examples (WINDEV): The encryption functions

[ + ] Using the encryption/decryption functions of WINDEV.
This example is used to:
- Encrypt a character string
- Decrypt a character string

Unit examples (WINDEV Mobile): The encryption functions

[ + ] Using the WLanguage encryption and decryption functions.
This example is used to:
- Encrypt a character string
- Decrypt a character string

Component : wd250std.dll