“Through that, they started trying to sabotage the whole network, by sending false information” about pro-democracy gatherings, he said, including wrong dates and locations.
The actions had a chilling effect on the protests, which have not gained momentum. Although young Sudanese have not given up, “they are more careful in using the Internet,” Adil Abdel Aati, an opposition party member, said in a Skype message.
A Sudanese official, Mandur al-Mahdi, was quoted recently in the Sudanese media as saying that ruling party “cyber-jihadists” had launched “online defense operations” to crush any effort to topple the government.
But Sudan’s charge d’affaires in Washington, Fatahelrahman Ali Mohammed, said authorities were simply trying to get their message out.
“It is something natural that the government would encourage the supporters to go to the Internet,” he said. “But I don’t have information that there is a campaign which is declared.” He said he also was unaware of anyone being forced to give up their passwords.
Syria’s government, which has long been accused of spying on Internet users, appeared to signal leniency when it lifted its ban on Facebook, YouTube and Twitter in February.
But since then, it has dispatched tanks and snipers to put down a wave of peaceful demonstrations. It has cut off electricity and phone service to cities hit by protests, crippling Internet use, and arrested bloggers. And there are signs of a somewhat more sophisticated campaign.
Recently, some Internet users in Syria discovered that their Facebook security certificates had been switched, allowing outsiders to track their log-in information and online activity.
“We don’t know who’s doing it. We assume it’s the Syrian Telecom,” which is affiliated with the government, said Jillian York, director of international freedom of expression at the San Francisco-based
Electronic Frontier Foundation.
After activists posted online videos of soldiers attacking protesters, government supporters began to upload footage that they said shows that the protesters are Islamist extremists or are using weapons, according to Tarif, the human rights activist.
“They run their own campaign to discredit the campaign of the revolution,” he said. In one case, activists say, a video purportedly showing Syrian protesters attacking police officers turned out to be footage from Iraq.
Syrian regime supporters also have been posting their version of events on foreign media sites, including that of The Washington Post.
The Syrian Embassy in Washington did not return calls for comments.
To help the embattled activists, Baer said, the State Department has funded “cyber-defense” training for 5,000 people in the past two years. The department is stepping up its efforts, with plans for additional training and new gizmos — such as a digital “secret handshake” to enable Internet users to know who they are chatting with online.
Guerra said users are often unaware of the extent to which governments monitor them.
“They’re just happy there’s Internet. They are oblivious as to how insecure it is for them,” he said. “That’s a huge problem.”
Staff writers Michael Birnbaum in Cairo and Liz Sly in Beirut and special correspondent Rebecca Hamilton contributed to this report.