(Delphi DLL) Create PKCS1 RSA Signature with PEM Private Key

See more RSA Examples

Demonstrates how to load a private key from a PEM file and create a PKCS1 RSA digital signature.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
pkey: HCkPrivateKey;
success: Boolean;
pkeyXml: PWideChar;
rsa: HCkRsa;
strData: PWideChar;
hexSig: PWideChar;

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

pkey := CkPrivateKey_Create();

// Load the private key from an RSA PEM file:
success := CkPrivateKey_LoadPemFile(pkey,'pvkey2_rsa.pem');

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

rsa := CkRsa_Create();

// Import the private key into the RSA object:
success := CkRsa_ImportPrivateKey(rsa,pkeyXml);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRsa__lastErrorText(rsa));
    Exit;
  end;

// Get the signature as hex.
CkRsa_putEncodingMode(rsa,'hex');

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

// Sign the string using the sha-1 hash algorithm.
// Other valid choices are "md2", "md5", "sha256",
// "sha384", and "sha512".
hexSig := CkRsa__signStringENC(rsa,strData,'sha-1');

Memo1.Lines.Add(hexSig);

Memo1.Lines.Add('Success!');

CkPrivateKey_Dispose(pkey);
CkRsa_Dispose(rsa);

end;