Asynchronous SSLSTREAM
I can't comment on how secure your code is, however there are a couple of other problems that I would like to point out. 

Clutter

Your using directives can be cut down to:

using System;
using System.Net;
using System.Net.Sockets;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;


Naming


Let me show you what I think of when I see a class called Sock:

You need to give that class a better name, for instance SslSocketMonitor. Actually, I don't know enough about your class to find a good name; use your brain to find a better one.
Let me show you what I think of when I see a class called Wrapper:

Because you are using it as a parameter to an event, this ought to be called something like SslSocketEventArgs, but certainly not Wrapper.
Decide on one naming convention and stick to it. You are using three different conventions for naming private fields:

private Dictionary&lt;string, byte&gt; Connections; // UpperCase
private Socket _sock;                         // _lowerCasePrefixed
private X509Certificate certificate;          // lowerCase

Your event names are nonstandard and not particularly clear.
Instead of AnnounceNewConnection try Connected,
instead of AnnounceDisconnection try Disconnected,
and instead of AnnounceReceive use ReceivedData.


API problems


.NET programmers are familiar with events. Therefore, it makes sense to implement the pattern properly:


SslSocketEventArgs (formerly Wrapper) needs to be derived from System.EventArgs 
Instead of using Action:

public event Action&lt;Wrapper&gt; AnnounceNewConnection;
public event Action&lt;Wrapper&gt; AnnounceDisconnection;
public event Action&lt;byte[], Wrapper&gt; AnnounceReceive;


use the more expressive and conventional EventHandler&lt;T&gt;:

public event EventHandler&lt;SslSocketEventArgs&gt; Connected;
public event EventHandler&lt;SslSocketEventArgs&gt; Disconnected;
public event EventHandler&lt;SslSocketEventArgs&gt; ReceivedData;

It's not safe to directly invoke event handlers as they could easily be null. So define the following extension method to safely invoke the event handlers:

public static class EventHandlerExtensions
{
    public static void InvokeSafely&lt;T&gt;(this EventHandler&lt;T&gt; eventHandler, 
                       object sender, T eventArgs) where T : EventArgs
    {
        if (eventHandler != null)
        {
            eventHandler(sender, eventArgs); // syntactic sugar for .Invoke
        }
    }
}



and replace all the usages:

Disconnected.InvokeSafely(this, wr);
Received.InvokeSafely(this, wr); // etc...

I'm not a fan of beginning listening in the constructor. It would be better to invoke that explicitly in a separate method.
There should be a way to cancel listening. Write a public method to enable this.


Programming errors


Your field Dictionary&lt;string, byte&gt; Connections is initialized but never used. Delete it.
You have lines like these spread throughout your code:

wr.sslStream.Close();
wr.sslStream.Dispose();


That scares me. What if you forgot to close it somewhere? It would be best to enclose all uses of the class in using statements where possible.
In ReceiveData, you make the following (constant) assignment:

SocketError error = SocketError.Disconnecting;


So the following condition will always be false:

if (error == SocketError.Success &amp;&amp; size != 0)


What you are probably trying to do is instead of catch (Exception):

catch (SocketException e)
{
    // handle properly!
    Console.WriteLine(e.SocketErrorCode);
}