The world's most popular messaging apps are failing to adequately protect users' security and privacy, according to Amnesty International. Amnesty looked at 11 of the most popular messaging apps and found big variations in security. Facebook Messenger and WhatsApp came out on top, with scores of 73 out of 100. "For example in WhatsApp, the application uses very strong encryption,” said Amnesty's Sherif Elsayed-Ali led the research, who led the research. “It does a very good job of telling people what kind of encryption it uses and how it protects people's information." Conversely, Skype — which is owned by software giant Microsoft — and Snapchat performed poorly. "They do not use end-to-end encryption, which is essentially a kind of encryption that means that only the sender and the receiver are able to read the messages," Elsayed-Ali said. Snapchat disputes Amnesty's conclusions, and says privacy and security are "foundation values." Microsoft told VOA in a statement: "Skype uses encryption and a range of other technical security measures, and we protect people's privacy through legal challenges, advocacy, and strong policies to notify customers when we receive government requests for their data." Amnesty's Elsayed-Ali says it’s not only personal privacy at stake. "Journalists all over the world who are trying to uncover corruption, trying to uncover abuses by government,” Elsayed-Ali said. “There are activists who are resisting repression in their countries. And they are being actively sought out by their governments, who are trying to find their information to disrupt their work and often to imprison them or persecute them." At the bottom of Amnesty's rankings was the Chinese firm Tencent, which owns the messaging apps WeChat and QQ. It scored zero out of 100.