Delphi DLL

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 DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: HCkCrypt2;
password: PWideChar;
sb: HCkStringBuilder;
passwordBase64: PWideChar;

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

crypt := CkCrypt2_Create();

// 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.

CkCrypt2_putCryptAlgorithm(crypt,'aes');
CkCrypt2_putKeyLength(crypt,256);

password := 'this is my password';
CkCrypt2_SetSecretKeyViaPassword(crypt,password);

// Examine the resulting SecretKey in hex:
Memo1.Lines.Add('Computed Secret Key = ' + CkCrypt2__getEncodedKey(crypt,'hex'));

// Now perform the same computation manually:
sb := CkStringBuilder_Create();

CkCrypt2_putHashAlgorithm(crypt,'md5');
CkCrypt2_putCharset(crypt,'utf-8');
CkCrypt2_putEncodingMode(crypt,'hex');
CkStringBuilder_Append(sb,CkCrypt2__hashStringENC(crypt,password));

passwordBase64 := CkCrypt2__encodeString(crypt,password,'utf-8','base64');
CkStringBuilder_Append(sb,CkCrypt2__hashStringENC(crypt,passwordBase64));

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

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

CkCrypt2_Dispose(crypt);
CkStringBuilder_Dispose(sb);

end;