Tor Project chief says it benefits from cyberspy leaks
22 August 2014 Last updated at 00:01 BST
Some US and UK cyberspies are deliberately undermining the efforts of their colleagues at the NSA and GCHQ who are trying to carry out surveillance of the "dark web", according to the leading developer of software used to access hidden parts of the internet.
Andrew Lewman, the Tor Project's executive director, alleges members of the two government bodies are regularly leaking it details of flaws in its code after the agencies discover them.
By fixing these flaws, the Tor Project can continue to protect users' anonymity on the net, he explained.
The agencies declined to comment.
Mr Lewman told the BBC's Leo Kelion that he could not prove cyberspies were leaking information, but the evidence strongly suggested that this was the case.