Pascal (Lazarus/Delphi)

openssl enc decrypt

See more Encryption Examples

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

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.BinData,
  Chilkat.Crypt2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  crypt: TCrypt2;
  fileData: TBinData;

begin
  success := False;

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

  crypt := TCrypt2.Create;

  //  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.SetEncodedKey('secret','openssl');

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

  //  Decrypt
  crypt.VerboseLogging := True;
  success := crypt.DecryptBd(fileData);
  WriteLn(crypt.LastErrorText);

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

  WriteLn('success = ' + success);


  crypt.Free;
  fileData.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.