Skype is a free (as in beer) voice over IP application. Many other VOIP applications exist, but some specific points make Skype very different, such as its peer-to-peer architecture, its ease to bypass firewalls and, last but not least, the impressive level of obfuscation that has been invested to prevent anybody from looking inside the software and its communications. This last point added to its increasing success gave birth to many myths on security issues around it.