The National Security Agency may release transparency reports on the amount of surveillance it is doing, according to its deputy director.
Speaking at the Ted conference, where leaker Edward Snowden spoke earlier in the week, NSA deputy director Richard Ledgett said Mr Snowden had put people's lives at risk.
He said letting "the bad guys" know NSA's methods made them harder to find.
But he said the agency should do more to reassure people about its work.
He defended the Prism surveillance system, saying it was "hugely relevant" in disrupting terrorist plots.
Mr Ledgett was beamed in to the Ted (Technology, Entertainment and Design) conference taking place in Vancouver via video link, in a similar manner to how Mr Snowden had appeared.
More transparency
He told the audience that he wanted to "inform the discussion with facts" rather than the "half-truths and distortions" he accused Mr Snowden of using.
But, he added, the ex-NSA agent's exposure of its programs and practices had opened up a global debate about the "balance between secrecy and transparency", that the agency wanted to fully engage with.
"There is a proposal to release transparency reports in the same way as the internet companies are doing," said Mr Ledgett.
He admitted that the NSA needed to be more transparent about its processes, authorities and oversight.
"We haven't done a good job on that," he said.
But he emphasised that all the work the agency does has been rubberstamped by the president, federal judges and Congress.
Of Mr Snowden he said: "It shows amazing arrogance that he knows better than the framework of the constitution."
His release of vast amounts of top secret documents outlining the work at the NSA had been hugely damaging, said Mr Ledgett.
"He put people's lives at risk.
"If our adversaries see our methods they will move away from using them. We have evidence that terrorists, smugglers and nation states have moved away. We are losing visibility into what our adversaries are doing," he said.
He said that the agency needed access to the global telecommunications system to monitor the activities of terrorists, traffickers and enemy states.
"It would be great if the bad guys used a corner of the internet. If they had a domain badguys.com, that would be awesome," he said.
"But we are all on the same network. I use the same email service as the terrorists. We need to be able to pick that apart to find what we need."
Along the way it is inevitable that agents will "encounter people going about their business" but the NSA uses what he called "minimisation procedures" to ensure little information is read.