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

Private Sub btnSendMail_Click() 

    Dim oSmtp As New EASendMailObjLib.Mail 
    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 VB 6.0 with digital signature" 

    ' Set email body
    oSmtp.BodyText = "this is a test email sent from VB 6.0 with digital signature" 

    ' 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

    ' Add digital signature
    If Not oSmtp.SignerCert.FindSubject("test@emailarchitect.net", _ 
        CERT_SYSTEM_STORE_CURRENT_USER, "my") Then 
        MsgBox oSmtp.SignerCert.GetLastError() 
        Exit Sub 
    End If 

    If Not oSmtp.SignerCert.HasPrivateKey Then 
        MsgBox "Signer certificate has not private key, " & _ 
             " this certificate can not be used to sign email!" 
        Exit Sub 
    End If 

    MsgBox "start to send email ..." 

    If oSmtp.SendMail() = 0 Then 
        MsgBox "email was sent successfully!" 
    Else 
        MsgBox "failed to send email with the following error:" & oSmtp.GetLastErrDescription() 
    End If 

End Sub