Delphi ActiveX

Manually Duplicate SetSecretKeyViaPassword

Demonstrates how to duplicate the password string to binary secret key computation of SetSecretKeyViaPassword.

This is a cryptographically weak way of generating a secret key from a password. The SetSecretKeyViaPassword method is deprecated and should not be used.

Delphi ActiveX

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;
password: WideString;
sb: TChilkatStringBuilder;
passwordBase64: WideString;

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

crypt := TChilkatCrypt2.Create(Self);

// The password string is transformed to a binary secret key by computing the 
// MD5 digest (of the utf-8 password) to obtain 16 bytes.  
// If the KeyLength is greater than 16 bytes, then the MD5 digest of the Base64 encoding 
// of the utf-8 password is added.  A max of 32 bytes of key material is generated, and 
// this is truncated to the actual KeyLength required.

crypt.CryptAlgorithm := 'aes';
crypt.KeyLength := 256;

password := 'this is my password';
crypt.SetSecretKeyViaPassword(password);

// Examine the resulting SecretKey in hex:
Memo1.Lines.Add('Computed Secret Key = ' + crypt.GetEncodedKey('hex'));

// Now perform the same computation manually:
sb := TChilkatStringBuilder.Create(Self);

crypt.HashAlgorithm := 'md5';
crypt.Charset := 'utf-8';
crypt.EncodingMode := 'hex';
sb.Append(crypt.HashStringENC(password));

passwordBase64 := crypt.EncodeString(password,'utf-8','base64');
sb.Append(crypt.HashStringENC(passwordBase64));

Memo1.Lines.Add('Manually Computed = ' + sb.GetAsString());

// The output is:
// Computed Secret Key = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36
// Manually Computed = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36
end;