(Delphi ActiveX) openssl enc decrypt

Demonstrates how to decrypt a file that was encrypted using "openssl enc".

This example shows how to decrypt what was created using this openssl command:

openssl enc -e -aes-256-cbc -in hamlet.xml -out hamlet.enc -pass file:./secret.txt

This example shows how to do this:

openssl enc -d -aes-256-cbc -in hamlet.enc -out hamlet_dec.xml -pass file:./secret.txt

Note: This example requires Chilkat v9.5.0.71 or later.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: TChilkatCrypt2;
fileData: TChilkatBinData;
success: Integer;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

crypt := TChilkatCrypt2.Create(Self);

// Use aes-256-cbc
crypt.CryptAlgorithm := 'aes';
crypt.CipherMode := 'cbc';
crypt.KeyLength := 256;

// We'll need to set the hash algorithm to either MD5 or SHA256.
// openssl version 1.0.* or earlier used MD5 by default
// openssl version 1.1.* uses SHA-256 for the password to secret key derivation.

// For example, if openssl 1.1.0 was used, we should do this:
crypt.HashAlgorithm := 'sha256';

// This example assumes openssl 1.0.2 was used to encrypt what we're now decrypting:
crypt.HashAlgorithm := 'md5';

// The openssl command we are duplicating is:
// 
//    openssl enc -d -aes-256-cbc -in hamlet.enc -out hamlet_dec.xml -pass file:./secret.txt
// 
// The file secret.txt contains the word "secret".  We could write code to load the contents
// of secret.txt, but instead we'll just do this:
crypt.SetSecretKeyViaPassword('secret');

// Load the file to be decrypted.
fileData := TChilkatBinData.Create(Self);
success := fileData.LoadFile('qa_data/openssl_enc/hamlet.enc');

// Decrypt
success := crypt.DecryptBd(fileData.ControlInterface);

// Save the decrypted output.
success := fileData.WriteFile('qa_output/hamlet_dec.xml');

Memo1.Lines.Add('success = ' + IntToStr(Ord(success)));
end;