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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, BinData, Crypt2;

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: HCkCrypt2;
fileData: HCkBinData;
success: Boolean;

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

crypt := CkCrypt2_Create();

// Use aes-256-cbc
CkCrypt2_putCryptAlgorithm(crypt,'aes');
CkCrypt2_putCipherMode(crypt,'cbc');
CkCrypt2_putKeyLength(crypt,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:
CkCrypt2_putHashAlgorithm(crypt,'sha256');

// This example assumes openssl 1.0.2 was used to encrypt what we're now decrypting:
CkCrypt2_putHashAlgorithm(crypt,'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:
CkCrypt2_SetSecretKeyViaPassword(crypt,'secret');

// Load the file to be decrypted.
fileData := CkBinData_Create();
success := CkBinData_LoadFile(fileData,'qa_data/openssl_enc/hamlet.enc');

// Decrypt
success := CkCrypt2_DecryptBd(crypt,fileData);

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

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

CkCrypt2_Dispose(crypt);
CkBinData_Dispose(fileData);

end;