Encoding shell codes to avoid detection

Let's now say that we have identified a vulnerability in an underlying service that we are testing. However, in this case, the box has got antivirus software installed. Any good antivirus software will contain all the signatures of well-known exploits, and typically the signatures for almost all the Metasploit exploit modules would be present. It is therefore imperative for us to use a methodology that would evade the antivirus detection. This means we need to use some sort of encoding or any other method to deliver our payload to avoid AV detection. There are three different ways that we can do this:

1. The most successful method is to develop a custom exploit in a language of your choice (Python/C/C++/Java). This method is useful, because a custom exploit will not have any AV signatures and would usually evade the AV protection. Alternatively...