public class ClientServerCertificates : IDisposable

Public Class ClientServerCertificates
	Implements IDisposable

using System;
using MailBee;
using MailBee.Pop3Mail;
using MailBee.Security;

class Sample
{
    static void Main(string[] args)
    {
        Pop3 pop = new Pop3();

        // Start SSL handshake on "connecting to server" stage (dedicated port connection).
        // If you wish to use STARTTLS (regular port connection), select UseStartTls value
        // (port would be 110 and SSL handshake would occur later on StartTls or Login call).
        pop.SslMode = SslStartupMode.OnConnect;

        // Open Personal store of certificates, attempt to find the certificate containing
        // "john" in the email address or name, and present this certificate to the server.
        CertificateStore store = new CertificateStore(CertificateStore.Personal,
            CertStoreType.System, null);
        CertificateCollection certs = store.FindCertificates("john",
            CertificateFields.EmailAddress | CertificateFields.Name);
        store.Dispose();
        if (certs.Count > 0)
        {
            pop.SslCertificates.Client = certs[0];
            Console.WriteLine("Client certificate set.");
        }
        else
        {
            // Most servers do not require clients to authenticate themselves via SSL
            // certificates so that anonymous SSL connection usually works too unless
            // your server is an exception.
            Console.WriteLine("Client certificate not set, the connection will be anonymous.");
        }

        // Tell MailBee to automatically validate the server certificate and
        // throw exception if any of the available conditions is not met.
        pop.SslCertificates.AutoValidation = CertificateValidationFlags.All;
        try
        {
            pop.Connect("mail.domain.com", 995);    // 995 is dedicated S/POP3 port.
            pop.Disconnect();
        }
        catch (MailBeeCertificateValidationException e)
        {
            // Server certificate is not valid.
            Console.WriteLine(e.Message);

            // Build a string which lists the names of all the flags
            // the certificate validation process has failed for.
            string reasons = string.Empty;
            CertificateValidationFlags flags = e.Status;
            int mask = 1;
            while (flags > 0)
            {
                CertificateValidationFlags flag = flags & (CertificateValidationFlags)mask;
                if (flag != CertificateValidationFlags.None)
                {
                    if (reasons.Length > 0)
                    {
                        reasons += ", ";
                    }
                    reasons += flag.ToString();
                    flags &= (CertificateValidationFlags)~mask;
                }
                mask <<= 1;
            }

            Console.WriteLine("Reasons: " + reasons);
        }
    }
}

Imports System
Imports MailBee
Imports MailBee.Pop3Mail
Imports MailBee.Security

Class Sample
    Shared Sub Main(ByVal args() As String)
        Dim pop As Pop3 = New Pop3

        ' Start SSL handshake on "connecting to server" stage (dedicated port connection).
        ' If you wish to use STARTTLS (regular port connection), select UseStartTls value
        ' (port would be 110 and SSL handshake would occur later on StartTls or Login call).
        pop.SslMode = SslStartupMode.OnConnect

        ' Open Personal store of certificates, attempt to find the certificate containing
        ' "john" in the email address or name, and present this certificate to the server.
        Dim store As CertificateStore = New CertificateStore(CertificateStore.Personal, _
                         CertStoreType.System, Nothing)
        Dim certs As CertificateCollection = store.FindCertificates("john", _
                            CertificateFields.EmailAddress Or CertificateFields.Name)
        store.Dispose()
        If certs.Count > 0 Then
            pop.SslCertificates.Client = certs(0)
            Console.WriteLine("Client certificate set.")
        Else
            ' Most servers do not require clients to authenticate themselves via SSL
            ' certificates so that anonymous SSL connection usually works too unless
            ' your server is an exception.
            Console.WriteLine("Client certificate not set, the connection will be anonymous.")
        End If

        ' Tell MailBee to automatically validate the server certificate and
        ' throw exception if any of the available conditions is not met.
        pop.SslCertificates.AutoValidation = CertificateValidationFlags.All
        Try
            pop.Connect("mail.domain.com", 995) ' 995 is dedicated S/POP3 port.
            pop.Disconnect()
        Catch e As MailBeeCertificateValidationException
            ' Server certificate is not valid.
            Console.WriteLine(e.Message)

            ' Build a string which lists the names of all the flags
            ' the certificate validation process has failed for.
            Dim reasons As String = String.Empty
            Dim flags As CertificateValidationFlags = e.Status
            Dim mask As Integer = 1
            While flags > 0
                Dim flag As CertificateValidationFlags = flags & CType(mask, CertificateValidationFlags)
                If flag <> CertificateValidationFlags.None Then
                    If reasons.Length > 0 Then
                        reasons &= ", "
                    End If
                    reasons &= flag.ToString()
                    flags = flags And CType(Not (mask), CertificateValidationFlags)
                End If
                mask <<= 1
            End While

            Console.WriteLine("Reasons: " & reasons)
        End Try
    End Sub
End Class