Microsoft has made it harder to monitor calls and chats over its Skype phone service on the mainland, said an advocacy group for freedom of expression, as the central government steps up censorship of the internet. Skype said on Monday it had ended an eight-year joint-venture with Hong Kong-based TOM Group - 51 per cent owned by billionaire Li Ka-Shing - and found a new partner on the mainland. "After careful analysis of the new Skype, we believe that Microsoft have lifted all censorship restrictions on their China product," the advocacy group GreatFire said yesterday. "All user calls, chats and login information are encrypted and being communicated directly to Microsoft via HTTPS. This is a complete about-face for Microsoft from the TOM-Skype era, when all information was processed by TOM and stored by TOM on servers located in China with absolutely no privacy controls in place." A Microsoft spokeswoman on the mainland declined to comment and a public relations official at Skype's Asia-Pacific regional office could not immediately be reached. Skype's new partner on the mainland is Guangming Founder (GMF), a joint-venture of Beijing-based newspaper Guangming Daily and the Founder Group, a Beijing technology conglomerate established by Peking University, according to the new GMF-Skype website. The Skype-TOM partnership had come under criticism from rights groups for allowing censorship and surveillance. Studies have shown the TOM-Skype service was subject to blacklisted keyword checks that could trigger monitoring of its users. Foreign internet companies must tread a careful path on the mainland to exploit bountiful business opportunities without compromising a carefully nurtured image as champions of open societies and free speech. In 2010, Google conducted a partial pull-out from the mainland on the basis of censorship and after it suffered a serious hacking episode. Google's search market share on the mainland fell to 1.7 per cent last month from 12 per cent in August 2010, although its mainland business has benefited from strong demand for its Android software. Websites such as Facebook, YouTube - which is owned by Google - and Twitter are all blocked on the mainland. Outside the mainland, Skype's security and privacy protection have been under the spotlight following revelations, disclosed by Edward Snowden in his leaks of US National Security Agency documents, that the online communication service was part of the NSA's PRISM programme to monitor communications via internet companies.