Classes

Class CryptFile() Professional

Class function of the CryptFile() class

Description

The CryptFile class provides encryption and decryption of files, such as text files. To encrypt a file, a crypt-provider object and a key-object is required. The crypt-provider determines the algorithm used for encryption, and the key-object provides the cipher key to be used by the crypt-provider.

SecureKey():destroy() can be called right after encrypting or decrypting a file. The key value is required during that operation.

Class methods
:new()
Creates an instance of the CryptFile class.
Instance variables
:bufferSize
Determines the buffer size for file encryption.
Methods
:encrypt()
Encrypts a file.
:decrypt()
Decrypts a file.
Examples
Crypting a file 
// In this example, a plain text file is encrypted using 
// a supplied key 

#include "crypt.ch" 

PROCEDURE MAIN(cFile, cKey) 
   LOCAL oAes 
   LOCAL oFile 
   LOCAL oKey 

   // setup key object 
   oKey := SecureKey():new() 
   oKey:setStrKey(cKey) 

   // use AES for encryption 
   oAes := AesCrypt():new(oKey) 
   oFile := CryptFile():new(oAes, oKey) 

   // now encrypt file in two buffers 
   oFile:bufferSize := FSize(cFile)/2 
   oFile:encrypt(cFile, cFile+".enc") 

   // destroy key 
   oKey:destroy() 
   ? cFile+".enc created" 
RETURN
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