Create PKCS1 RSA Signature with PEM Private Key

Demonstrates how to load a private key from a PEM file and create a PKCS1 RSA digital 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
pkey: CHILKATCERTIFICATELib_TLB.IPrivateKey;
success: Integer;
pkeyXml: String;
rsa: TChilkatRsa;
strData: String;
hexSig: String;

begin
pkey := TprivateKey.Create(Self).ControlInterface;

//  Load the private key from an RSA PEM file:
pkey.LoadPemFile('pvkey2_rsa.pem');

//  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;