RSA Signature with Certificate's Private Key from PFX

Demonstrates how to use a certificate's private key from a PFX file to create an RSA signature.

Download Chilkat RSA ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATCERTIFICATELib_TLB,
    CHILKATRSALib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
certStore: CHILKATCERTIFICATELib_TLB.IChilkatCertStore;
cert: IChilkatCert;
pkey: CHILKATCERTIFICATELib_TLB.IPrivateKey;
pkeyXml: String;
rsa: TChilkatRsa;
strData: String;
hexSig: String;

begin


//  Create an instance of a certificate store object, load a PFX file,
//  locate the certificate we need, and use it for signing.
//  (a PFX file may contain more than one certificate.)
certStore := CoChilkatCertStore.Create();

//  The 1st argument is the filename, the 2nd arg is the
//  PFX file's password:
success := certStore.LoadPfxFile('chilkat.pfx','test');
if (success <> 1) then
  begin
    ShowMessage(certStore.LastErrorText);

  end;

cert := certStore.FindCertBySubject('Chilkat Software, Inc.') As IChilkatCert;
if (cert = nil ) then
  begin
    ShowMessage(certStore.LastErrorText);

  end;

pkey := cert.ExportPrivateKey() As CHILKATCERTIFICATELib_TLB.IPrivateKey;
if (pkey = nil ) then
  begin
    ShowMessage(cert.LastErrorText);

  end;

//  Get the private key in XML format:
pkeyXml := pkey.GetXml();

rsa := TChilkatRsa.Create(Self);

//  Any string argument automatically begins the 30-day trial.
success := rsa.UnlockComponent('30-day trial');
if (success <> 1) then
  begin
    ShowMessage('RSA component unlock failed');

  end;

//  Import the private key into the RSA component:
success := rsa.ImportPrivateKey(pkeyXml);
if (success <> 1) then
  begin
    ShowMessage(rsa.LastErrorText);

  end;

//  This example will sign a string, and receive the signature
//  in a hex-encoded string.  Therefore, set the encoding mode
//  to "hex":
rsa.EncodingMode := 'hex';

strData := 'This is the string to be signed.';

//  Sign the string using the sha-1 hash algorithm.
//  Other valid choices are "md2" and "md5".
hexSig := rsa.SignStringENC(strData,'sha-1');

Memo1.Lines.Add(hexSig);

ShowMessage('Success!');
end;