The articles specifically mention VPNs, and the SSL and TLS protocols are also compromised allowing the intelligence agencies to monitor Google, Facebook, Microsoft and Yahoo traffic.
The reports don’t reveal which algorithms have been compromised and where the supposed backdoors are installed.
From a technical point of view it’s nearly impossible to break the most secure forms of VPN encryption in realtime. That said, older algorithms have been cracked in the past and the NSA never ceases to amaze.
TorrentFreak has asked the operators of some VPN providers to share their thoughts on the revelations, and we may follow up on this later.