(Delphi ActiveX) RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

See more Apple Keychain Examples

Demonstrates how RSA sign the utf-8 byte representation of a string to get the signature in base64 format.

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

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
cert: TChilkatCert;
success: Integer;
sb: TChilkatStringBuilder;
crlfLineEnding: Integer;
i: Integer;
rsa: TChilkatRsa;
stringToSign: WideString;
sigBase64: WideString;

begin
// Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
// this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

// Chilkat automatically detects and determines the way in which the HSM is used,
// which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

cert := TChilkatCert.Create(Self);

// Set the token/smartcard PIN prior to loading.
cert.SmartCardPin := '123456';

// Specify the certificate by its common name.
success := cert.LoadFromSmartcard('cn=chilkat-rsa-2048');
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Signing with cert: ' + cert.SubjectCN);

// Create a string to be hashed and signed.
sb := TChilkatStringBuilder.Create(Self);
crlfLineEnding := 1;

for i := 0 to 10 do
  begin
    sb.AppendLine('This is a test.',crlfLineEnding);
  end;

rsa := TChilkatRsa.Create(Self);

// Use the certificate's private key for signing.
success := rsa.SetX509Cert(cert.ControlInterface,1);
if (success = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

// Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
// Return the signature in base64 format.
rsa.EncodingMode := 'base64';
rsa.Charset := 'utf-8';
stringToSign := sb.GetAsString();
sigBase64 := rsa.SignStringENC(stringToSign,'sha256');
if (rsa.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('RSA signature as base64: ' + sigBase64);
end;