Skype-to-Skype voice, video, and instant message conversations are encrypted. Microsoft-owned Skype “regularly scans message contents for signs of fraud, and company managers may log the results indefinitely,” Ars Technica reports. Skype wouldnt confirm or deny whether it could facilitate wiretapping requests when asked point blank. A month after the May 2011 purchase, Microsoft was granted a patent for legal intercept technology, designed to be used with VOIP services like Skype to silently copy communication transmitted via the communication session”]
Source: https://nakedsecurity.sophos.com/2013/05/22/microsofts-reading-skype-messages/