Unit Unit1; 

Interface 

Uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls, EASendMailObjLib_TLB; // add EASendMail Unit 

Type 
  TForm1 = Class(TForm) 
    Button1: TButton; 
    Procedure Button1Click(Sender: TObject); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
  End; 

Const 
  CRYPT_MACHINE_KEYSET = 32; 
  CRYPT_USER_KEYSET = 4096; 
  CERT_SYSTEM_STORE_CURRENT_USER = 65536; 
  CERT_SYSTEM_STORE_LOCAL_MACHINE = 131072; 

Var 
  Form1: TForm1; 

Implementation 

{$R *.dfm} 

Procedure TForm1.Button1Click(Sender: TObject); 
Var 
  oSmtp : TMail; 
Begin 
  oSmtp := TMail.Create(Application); 
  oSmtp.LicenseCode := 'TryIt'; 

  // Set your sender email address
  oSmtp.FromAddr := 'test@emailarchitect.net'; 

  // Add recipient email address
  oSmtp.AddRecipientEx( 'support@emailarchitect.net', 0); 

  // Set email subject
  oSmtp.Subject := 'test email from Delphi with digital signature'; 

  // Set body text
  oSmtp.BodyText := 'this is a test email sent from Delphi with digital signature'; 

  // Add digital signature
  If Not oSmtp.SignerCert.FindSubject('test@emailarchitect.net', 
    CERT_SYSTEM_STORE_CURRENT_USER, 'my' ) Then 
    Begin 
      ShowMessage( oSmtp.SignerCert.GetLastError()); 
      exit; 
    End; 

  If Not oSmtp.SignerCert.HasCertificate Then 
    Begin 
      ShowMessage( 'Signer certificate has no private key, ' + 
      'this certificate can not be used to sign email'); 
    End; 

  // Your SMTP server address
  oSmtp.ServerAddr := 'smtp.emailarchitect.net'; 

  // User and password for ESMTP authentication, if your server doesn't require
  // user authentication, please remove the following codes
  oSmtp.UserName := 'test@emailarchitect.net'; 
  oSmtp.Password := 'testpassword'; 

  // If your SMTP server requires SSL connection, please add this line
  // oSmtp.SSL_init();

  ShowMessage( 'start to send email ...' ); 

  If oSmtp.SendMail() = 0 Then 
    ShowMessage( 'email was sent successfully!' ) 
  Else 
    ShowMessage( 'failed to send email with the following error: ' 
    + oSmtp.GetLastErrDescription()); 

End; 

End.