Skype has reacted strongly to actions of a Russian researcher who claimed to have reverse engineered the VoIP software's protocol.
Efim Bushmanov said in a blog post he wanted to make Skype open source, although noting he had not completely reverse engineered the protocol, nor had he created any alternative software from it.
"This unauthorised use of our application for malicious activities like spamming/phishing infringes on Skype's intellectual property," Skype said in a statement.
"We are taking all necessary steps to prevent/defeat nefarious attempts to subvert Skype's experience. Skype takes its users' safety and security seriously and we work tirelessly to ensure each individual has the best possible experience."
Skype has kept its protocol to itself since its inception in 2003. The company's network is not interoperable with the majority of other VoIP networks which don't have Skype's permission.
Paul Ducklin, head of technology in the Asia Pacific region for Sophos, said Skype's new owner, Microsoft, could actually benefit from an open source version of the software.
"Open-source Skype implementations for Linux and OS X would probably be in Microsoft's overall interest - Microsoft could simply give up on the existing Linux and OS X code bases without creating any bitterness amongst those communities," Ducklin said in a blog post.
"And if Microsoft can build an attractive-enough back-end service for Skype, it will be able to convert Skype from a loss-making peer-to-peer pseudo-telephone company into yet another handy reason to sign up for a Microsoft LiveID and to join the fun in the Cloud according to Redmond."
In allowing Skype code to become open, others may be distracted from creating genuine alternatives, Ducklin suggested.
"Open-source Skype would probably distract from any open-source projects aimed at creating a genuine alternative," he added.
"We'd just end up with multiple choices of client for the Skype service, rather than a complete competitive service."
