fEncrypt (Function)

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Error handling
Operating mode in Windows Vista (and later)
Encrypting/Decrypting a character string

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fEncrypt (Function)

In french: fCrypte

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

Encrypts a file in binary or ASCII format.

Remarque: This file can be decrypted with fDecrypt.

Example

See additional examples

// Encrypt a file
ResEncrypt = fEncrypt("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 get more details on the error, use ErrorInfo with the errMessage constant.

<Path of file to encrypt>: Character string

Name and full (or relative) path of the file to encrypt (up to 260 characters). A UNC path can be used.
This parameter can be in Ansi or Unicode format.
This parameter can correspond to a full path or a path relative to the current directory (returned by fCurrentDir). This parameter is case-sensitive.
Reminder: In Android, the file system is read-only on the device and on the emulator. An application can only write to its installation directory or one of its subdirectories, as well as to the external memory (SDCard).
This parameter can correspond to a full path or a path relative to the current directory (returned by fCurrentDir). This parameter is case-sensitive.
Reminder: On iPhone/iPad, both on the device and in the emulator, the file system is read-only.. An application can only write to its installation directory or one of its subdirectories.

<Path of encrypted file>: Character string

Name and full (or relative) path of the encrypted file (up to 260 characters). A UNC path can be used.
This parameter can be in Ansi or Unicode format.
This parameter can correspond to a full path or a path relative to the current directory (returned by fCurrentDir). This parameter is case-sensitive.
Reminder: In Android, the file system is read-only on the device and on the emulator. An application can only write to its installation directory or one of its subdirectories, as well as to the external memory (SDCard).
This parameter can correspond to a full path or a path relative to the current directory (returned by fCurrentDir). This parameter is case-sensitive.
Reminder: On iPhone/iPad, both on the device and in the emulator, the file system is read-only.. An application can only write to its installation directory or one of its subdirectories.

<Password>: Character string

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:
cryptFast
(Default value) Priority is given to the encryption speed (algorithm on 128 bits).
The algorithm used will be a Blowfish algorithm.
This constant is not available.
The algorithm used will be a Blowfish algorithm with 16 rounds.
cryptNone No encryption is performed.
cryptRC516 Priority is given to the encryption security (RC5 algorithm on 16 rounds).
This constant has no effect.
cryptSecure Priority is given to the encryption security (RC5 algorithm on 128 bits).
The algorithm used will be a PBE algorithm (Password Based Encryption).
The algorithm used will be a 128-bit RIJNDAEL algorithm.

<Format of encrypted file>: Optional Integer constant

Indicates the format of the encrypted 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.
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.
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.
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.

This parameter is ignored.

Remarks

Error handling

fEncrypt throws 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 work 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).

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

Programming tip: If you need to manipulate / modify files or directories, without needing administrator privileges, it is advisable:

avoid writing to the Windows directory or to the "Program Files" directory,
use the system directory of the application (returned by SysDir with the srAppDataCommun constant, for example).

Remark: Under Windows Vista (and higher), the virtualization mechanism makes applications Vista-compatible.. 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.

Encryption in PHP
In PHP, the BlowFish encryption (cryptFast constant) and the RINJDAEL encryption (cryptSecure constant) are based on the MCrypt library. This library is commonly used by the PHP hosting providers and therefore it is always enabled. This library can be downloaded from the PHP site.

To enable (if necessary) this library locally, the following elements are required:

PHP installed.
the PHP.INI file found in the Windows directory must include the "extension=php_mcrypt.dll" line.
the php_mcrypt.dll file must exist in the directory of PHP extensions. This directory is defined in the PHP.INI file by the "extension_dir" variable.

Encryption in Android/Java and decryption by a WINDEV application (or conversely)
Warning: the encryption/decryption algorithms used in Java and Android are not the same as those used by WINDEV.. Therefore, you cannot encrypt a file in Java or Android and decrypt it with WINDEV and vice versa.

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: wd300std.dll